Systems and methods for fluid access control for skin graft systems

Abstract

A skin graft system includes a handheld device, a cartridge, and a device shield. The handheld device includes a device housing forming an interior for securing the drive system. The cartridge includes a plurality of hollow microneedles surrounded by a peripheral housing and configured to be operated by a drive system to extend and retract across the peripheral housing into a subject to retrieve tissue during skin grafting. The device shield is formed from a polymer extending from an inner opening dimensioned to extend around the peripheral housing to position the outer edge over the device housing such that during performing a skin graft procedure using the skin graft system, the outer edge is positioned over the device housing. Fluid from the periphery of the peripheral housing of the cartridge is controlled to enter the interior of the device housing.

Description

This application is a divisional application of Chinese Patent Application No. 202080083331.X, which is the national stage application in China of the international application No. PCT / US2020 / 053413, entitled "Systems and Methods for Fluid Inflow Control in a Skin Grafting System", filed on May 31, 2022. Cross - Reference to Related Applications

[0001] This application claims the priority of U.S. Application No. 16 / 592,312, filed on October 3, 2019, the entire disclosure of which is incorporated herein by reference for all purposes. Technical Field

[0002] The subject matter of the present disclosure generally relates to a skin grafting system, and more particularly, to a system that may include a device for harvesting and dispersing skin microcolumns. Background Art

[0003] An autograft may refer to tissue transplanted from one part of an individual's body (e.g., a "donor site") to another part (e.g., a "recipient site"). For example, autografts can be used to replace missing skin and other tissues and / or to accelerate healing resulting from trauma, injury, burns, surgery, and birth defects. The availability of tissue for autotransplantation can be limited by the characteristics of the candidate donor site, including the quantity and / or total area of the tissue graft, the healing performance of the donor site, the similarity between the donor site and the recipient site, aesthetic considerations, etc.

[0004] Skin grafting can be performed surgically. For example, traditional autograft surgery may include: excising or surgically removing burned tissue; selecting a donor site, which can be an area from which healthy skin is removed to be used as a covering for the cleaned burned area; and harvesting, where a graft can be removed from the donor site (e.g., using an instrument similar to an electric razor). Such an instrument (e.g., a dermatome) can be configured to gently scrape a thin layer of tissue (e.g., about 10 / 1000 inches thick for a split-thickness skin graft) from the skin at an undamaged donor site to be used as a skin graft. Subsequently, the skin graft can be placed on the cleaned wound for healing. The donor skin tissue is removed to such a depth that the donor site can heal itself, and the process is similar to the healing process of a second-degree burn.

[0005] Traditionally, sheet grafts and mesh grafts are two types of autologous grafts often used for permanent wound coverage. A sheet graft can refer to a piece of skin tissue removed from an undamaged donor site on the body, and the process can be called harvesting. The size of the donor skin piece used can be approximately the same as the size of the damaged area. The sheet graft can be placed over the excised wound and stapled or otherwise secured in place. The donor skin tissue for the sheet graft may not stretch significantly, and a sheet graft slightly larger than the damaged area to be covered can be harvested, as the transplanted tissue may often shrink slightly after harvesting.

[0006] Sheet grafts can provide an improved appearance for the repaired tissue site. For example, if large areas of the face, neck, and hands are damaged, sheet grafts can be used on these areas so that these more visible body parts will not appear as scarred after healing. Sheet grafts can be used to cover entire burned or damaged skin areas. After placement of the sheet graft, small areas of the sheet graft may be lost because fluid accumulation (such as a hematoma) may occur under the sheet graft after placement.

[0007] Mesh skin grafts can be used to cover larger areas of open wounds that may be difficult to cover with sheet grafts. The meshing of the skin graft can help the skin tissue from the donor site expand to cover a larger area. When the skin graft is placed on the wound, it can also facilitate the drainage of blood and body fluids from under the skin graft, which can help prevent graft loss. The expansion ratio of the mesh graft (e.g., the ratio of the area of the unstretched graft to the area of the stretched graft) can typically be between about 1:1 and 1:4. For example, the donor skin can be meshed at a ratio of about 1:1 or 1:2, and a larger expansion ratio may result in a more fragile graft, scarring when the mesh graft heals, and / or an extended healing time.

[0008] Traditional graft meshing procedures can involve passing the donor skin tissue through a machine that cuts slits through the tissue, which can help with expansion in a pattern similar to a fishnet or chain-link fence. Healing occurs when the spaces between the meshes of the stretched graft, also known as gaps or voids, are filled with new epithelial skin growth. However, mesh grafts may be less durable grafts than sheet grafts, and after the graft heals, large mesh grafts may result in permanent scarring.

[0010] A xenograft or heterograft can refer to skin taken from one of a variety of animals, such as a pig. Heterograft skin tissue can also be used to temporarily cover an excised wound before placement of a more permanent autograft, and allograft skin tissue may be used due to the limited availability and / or high cost of human skin tissue. Covering a wound with a xenograft or allograft is generally a temporary procedure and can be used until harvesting and placement of an autograft is feasible.

[0011] Harvesting transplant tissue from a donor site generally results in an undesirably large area of tissue damage to the donor site. On the other hand, small areas of skin damage adjacent to healthy tissue are well tolerated and may heal quickly. Healing of such small wounds can be performed by techniques such as "focal photothermolysis" or "focal dermal reconstruction", in which a pattern of damage of small dimensions can be created in the skin tissue. These exemplary techniques are described, for example, in U.S. Patent No. 6,997,923. The small-scale pattern of damage can heal quickly by regrowth of healthy tissue and can further provide desirable effects such as tightening of the skin without significant scarring.

[0012] The mechanism of tissue transplantation provides an opportunity for a transplantation tool to come into contact with the clinical "soil" (e.g., blood, tissue, hair, etc.) from a patient. In split-thickness and full-thickness skin grafts (both of which harvest tissue extending below the epidermis), local damage to capillaries and / or blood vessels often results in bleeding. The extent of bleeding is affected by patient factors such as anticoagulant medications.

[0013] Accordingly, it would be advantageous to have further systems and methods for protecting reusable clinical tools from the clinical soil without sacrificing the functionality of the skin harvesting process. SUMMARY OF THE INVENTION

[0014] In one aspect, the present disclosure provides a skin grafting system having a handheld device, a cartridge, and a disposable device shield. The handheld device includes a device housing that forms an interior for a fixed drive system. The cartridge includes a plurality of hollow microneedles that are surrounded by an outer housing and are configured to be operated by the drive system to extend and retract across the outer housing into a subject to harvest tissue. The device shield is formed of a polymer extending from an inner opening to an outer edge, the inner opening sized to extend around the outer housing to position the outer edge above the device housing, thereby preventing fluid from entering the interior of the device housing from around the outer housing of the cartridge during a skin grafting procedure performed using the skin grafting system.

[0015] In another aspect, the present disclosure provides a skin grafting system having a handheld device, a cartridge, and a device shield. The handheld device includes a device housing having an engagement groove formed therein and forming an interior for a fixed drive system. The cartridge is removably engaged with the handheld device through the engagement groove and includes a plurality of hollow microneedles surrounded by an outer peripheral housing and configured to be operated by the drive system to extend and retract across the outer peripheral housing into a subject to harvest tissue during a skin grafting procedure. The device shield is formed of a flexible membrane extending from an inner opening to an outer edge, the inner opening sized to extend around and move along the outer peripheral housing to form a barrier over the engagement groove when the outer edge is disposed to extend over the device housing.

[0016] The following description and the drawings set forth in detail certain illustrative embodiments of the present disclosure. However, these embodiments merely illustrate several of the various ways in which the principles of the present disclosure may be utilized. Other embodiments and features will become apparent from the following detailed description of the present disclosure when considered in conjunction with the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following description is provided with reference to the drawings, in which like reference numerals denote like elements.

[0018] Figure 1 is a top perspective view of a skin grafting system including a cartridge according to some embodiments of the present disclosure.

[0019] Figure 2A is Figure 1 a front perspective view of the system.

[0020] Figure 2B is a top view of a user interface that may be included in the Figure 2A system according to some embodiments of the present disclosure.

[0021] Figure 3A is according to some embodiments of the present disclosure Figure 2A a cross-sectional view of the handheld device.

[0022] Figure 3B is a cross-sectional view corresponding to the Figure 2A handheld device housing according to some embodiments of the present disclosure.

[0023] Figure 4A is a rear perspective view of an internal drive assembly and associated elements corresponding to the Figure 2A handheld device according to some embodiments of the present disclosure.

[0024] Figure 4B is a right perspective view of a left frame assembly corresponding to the Figure 4A internal components according to some embodiments of the present disclosure.

[0025] Figure 4C is a right - perspective isometric view of a right - frame component corresponding to the internal components of Figure 4A in accordance with some embodiments of the present disclosure.

[0026] Figure 4D is a rear - perspective isometric view of a horizontal - component assembly corresponding to the internal components of Figure 4A in accordance with some embodiments of the present disclosure.

[0027] Figure 4E is a rear - perspective isometric view of a vertical - component assembly corresponding to the internal components of Figure 4A in accordance with some embodiments of the present disclosure.

[0028] Figure 5A is an isometric view of a cartridge - component assembly including a removable cover in accordance with some embodiments of the present disclosure.

[0029] Figure 5B is an isometric view of a cartridge corresponding to the cartridge of Figure 5A in accordance with some embodiments of the present disclosure.

[0030] Figure 6A is an example of a microneedle and pin assembly capable of harvesting tissue in accordance with some embodiments of the present disclosure.

[0031] Figure 6B is an isometric view of a microneedle and pin assembly capable of harvesting tissue in accordance with some embodiments of the present disclosure.

[0032] Figure 6C is a plan view of a microneedle array in accordance with some embodiments of the present disclosure.

[0033] Figure 7 is a program - flow chart illustrating a method of harvesting and disseminating tissue in accordance with some embodiments of the present disclosure.

[0034] Figure 8 is a front view of a device shield applied to a cartridge in accordance with some embodiments of the present disclosure.

[0035] Figure 9 is an isometric view of a Figure 8 device shield applied to a skin - grafting system in accordance with some embodiments of the present disclosure.

[0036] Figure 10 is a cross - sectional view of a Figure 8 device shield applied to a skin - grafting system in accordance with some embodiments of the present disclosure. Detailed Description

[0037] The following discussion is provided to enable a person skilled in the art to make and use the systems and methods of the present disclosure. Various modifications to the illustrated embodiments will be apparent to those skilled in the art, and the generic principles herein may be applied to other embodiments and applications without departing from the scope of the embodiments of the present disclosure. Accordingly, the embodiments of the present disclosure are not intended to be limited to the illustrated embodiments, but rather to be accorded the widest scope consistent with the principles and features disclosed herein.

[0038] The detailed description should be read with reference to the drawings. The drawings depict selected embodiments and are not intended to limit the scope of the embodiments of the present disclosure. Those skilled in the art will recognize that the examples provided herein have many useful alternatives and fall within the scope of the embodiments of the present invention. Further, it should be understood that the terminology and phrases used herein are for the purpose of description and should not be regarded as limiting. As used herein, "including", "comprising", or "having" and their variants are meant to include the items listed thereafter and their equivalents as well as additional items.

[0039] Unless otherwise specified or limited, the terms "mounted", "connected", "supported", and "coupled" and their variants are used broadly and include both direct and indirect mounting, connection, support, and coupling. Further, "connected" and "coupled" are not limited to physical or mechanical connection or coupling. As used herein, unless otherwise expressly stated, "connected" means that one element / feature is directly or indirectly connected to another element / feature, and not necessarily electrically or mechanically. Similarly, unless otherwise expressly stated, "coupled" means that one element / feature is directly or indirectly coupled to another element / feature, and not necessarily electrically or mechanically.

[0040] Embodiments of the present disclosure may be described herein in terms of functional and / or logical block components and various processing steps. It should be understood that such block components may be implemented by any number of hardware, software, and / or firmware components configured to perform the specified functions. For example, embodiments may employ various integrated circuit components, such as, digital signal processing elements, logic elements, diodes, etc., which may perform various functions under the control of one or more processors or other control devices. Other embodiments may employ program code, or code in combination with other circuit components.

[0041] As described above, the present disclosure generally relates to a skin grafting system, and more particularly, to a system that may include a device for harvesting and dispensing skin microcolumns. In some cases, the process of harvesting skin microcolumns may include penetrating donor site tissue. Although typically minimal, harvesting microcolumns often results in local bleeding. The amount of blood at the donor site can depend on a variety of factors, such as the number of tissue punctures / perforations, the number of harvesting procedures performed in a single tissue area, the number of harvesting procedures performed using a single cartridge (described below), patient blood pressure, platelet count, medications, donor site handling, and / or complications. In some cases, it may be advantageous to prevent blood from contacting and / or entering components of the skin grafting system. Specifically, it may be advantageous to prevent blood from entering reusable elements of the skin grafting system.

[0042] For example, healthcare facilities typically have standard cleaning, disinfection, and / or sterilization procedures that must be performed when instruments are reused between patients. Specifically, to minimize the risk of infection transmission, all blood and body substances should be treated as potentially infectious. For complex instruments, blood entering the instrument housing can result in procedure delays, lengthy sterilization processes, and / or instrument replacement (along with associated costs), among other things. Accordingly, the present disclosure includes a system for preventing blood from entering a hand-held device (e.g., a reusable hand-held device) corresponding to a skin grafting system.

[0043] Now referring Figure 1 to, there is shown a skin grafting system 3000 in accordance with some embodiments of the present disclosure. In some configurations, the skin grafting system 3000 may be configured to harvest and dispense donor tissue. As shown, the skin grafting system 3000 may include a hand-held device 1000 (reusable) and a cartridge assembly 2000. As will be described in more detail below, the cartridge assembly 2000 may include a cartridge 2002 and a cartridge lid 2004. According to some configurations, the cartridge 2002 may include a microneedle and pin array 2006. Notably, the cartridge 2002 may include a simplified microneedle array 2006 (i.e., without pins).

[0044] As Figures 1 to 2B shown, the hand-held device 1000 may include an engagement slot 1002 configured to receive the cartridge assembly 2000. A loading door 1004 is capable of being in an "open" position (e.g., see Figure 1 ) and a "closed" position (e.g., see Figures 2A to 2B) move therebetween. In some configurations, the loading door 1004 can be hinged and further configured to open and close above the loading aperture 1006. The handheld device 1000 can include a door sensor that can determine the position of the loading door 1004. Depending on the needs of the user, the size of the loading aperture 1006 can be designed to enable the cartridge assembly 2000 to slide in and out of the engagement slot 1002. Advantageously, the cartridge assembly 2000 can be single-use and / or disposable (e.g., including multiple uses for a single patient), while the handheld device 1000 can be designed for multiple uses. As Figure 2A shown, the handheld device 1000 can also include a trigger 1014. The trigger 1014 can be configured to activate the collection process and / or the dispensing process in response to a selection via the user interface 1008 and / or a trigger input from the user. In some configurations, the handheld device 1000 can include an indicator light 1016. The indicator light 1016 can be positioned such that the user can easily view the indicator light 1016 during collection and / or dispensing.

[0045] In some configurations, the handheld device 1000 can include a user interface 1008. As shown, the user interface 1008 can include a preparation input section 1018, an indicator light 1020, and / or a dispensing input section 1022. In some configurations, the indicator light 1020 can operate in the same or a similar manner as the indicator light 1016 (described above). Since the skin grafting system 3000 is used in accordance with a skin grafting process such as will be described, the preparation input section 1018, the indicator lights 1016, 1020, and the dispensing input section 1022 can provide the user with visual feedback corresponding to the current operation of the skin grafting system 3000.

[0046] Now referring to Figures 3A to 3B , a cross-sectional view of the handheld device 1000 according to a configuration of the present disclosure is shown. The handheld device 1000 is shown to include various internal controllers. In some configurations, the handheld device 1000 can include a power module 1028, a solenoid controller 1030, and / or a main controller 1032. The power module 1028 can be in electrical communication with a power input 1038. In some configurations, the drive system can include a solenoid that communicates with the solenoid controller 1030.

[0047] Still referring to Figures 3A to 3B, in some configurations, the handheld device 1000 may include a housing 1036. The housing 1036 may include a left half-shell and a right half-shell. In some configurations, each of the left half-shell, the right half-shell, the loading door 1004, and the housing mounting cover may be injection molded separately. The left half-shell and the right half-shell may be composed of a hard plastic substrate and, in certain configurations, may be composed of softer elastomeric molded sections. Similarly, the loading door 1004 and the housing mounting cover may be composed of a hard plastic substrate. In some configurations, the interior of the housing 1036 may interface with internal components. As an example, ribs may be attached to the interior of the housing 1036 and may be configured to support various printed circuit boards (PCBs). The ribs can separate the PCBs (e.g., the power module 1028, the solenoid controller 1030, and the main controller 1032) from internal moving parts. Additionally, in some configurations, the housing 1036 can support the internal subassembly 1034 via pins and shock-absorbing sheaths. This can attenuate the operating shocks (e.g., from the user, from the operation of internal moving parts) of the internal subassembly 1034 and protect the internal subassembly 1034 from damage caused by external shocks (e.g., from dropping the handheld device 1000).

[0048] Now referring to Figures 4A to 4E , various internal components corresponding to the handheld device 1000 are shown according to some configurations. Figure 4A The internal subassembly 1034 is shown, which may include a left frame assembly 1040a, a right frame assembly 1040b, a horizontal component assembly 1044, and / or a vertical component assembly 1046. Each of the left frame assembly 1040a and the right frame assembly 1040b may include a respective flipper assembly (e.g., a left flipper assembly 1048a, a right flipper assembly 1048b). In some configurations, the horizontal component assembly 1044 may include a horizontal motor 1050. Additionally, the vertical component assembly 1046 may include a solenoid 1052.

[0049] Still referring to Figures 4A to 4E , particularly Figures 4B to 4C, further exemplary details of the left frame component 1040a and the right frame component 1040b according to some configurations are shown. In some configurations, the left frame component 1040a and the right frame component 1040b may be the same or substantially similar (e.g., symmetric). As shown, the left frame component 1040a may include a left flipper component 1048a attached to the first side of the left frame. Additionally, the left frame component 1040a may include fiducial sensors 1060a, 1060b attached to the second side of the left frame. The fiducial sensors 1060a, 1060b may communicate with the position sensing linear slide 1054 and the position sensing fiducial 1062. In some configurations, the left frame component 1040a may include position sensing springs 1056a, 1056b that may contact the tissue interface 1058a. The tissue interface 1058a may be located on the third side of the left frame. In some configurations, the left frame component 1040a may be attached to a portion of the vertical component assembly 1046 via screws and alignment pins or other attachment systems.

[0050] In some configurations, the right frame component 1040b may include fiducial sensors 1060c, 1060d attached to the first side of the right frame. The fiducial sensors 1060c, 1060d may communicate with the position sensing linear slide 1054 and the position sensing fiducial 1062. Additionally, as shown, the right frame component 1040b may include a right flipper component 1048b attached to the second side of the right frame. In some configurations, the right frame component 1040b may include position sensing springs 1056c, 1056d that may contact the tissue interface 1058b. The tissue interface 1058b may be located on the third side of the right frame. In some configurations, the right frame component 1040b may be attached to a portion of the vertical component assembly 1046 via screws and alignment pins.

[0051] The flipper components 1048a, 1048b may include a flipper mounting block 1066 and a flipper motor 1068. In some configurations, the flipper mounting block 1066 may be made of a dielectric material. The flipper motor 1068 may be connected to (and control) the flipper drive pulleys 1070a, 1070b. Bearings (e.g., thrust bearings) 1072 may support the axial load applied to the flipper 1074 by the needle top plate (e.g., the needle top plate 1112 described below). The flipper 1074 may rotate according to motor actuation, and the flipper drive pulleys 1070a, 1070b may prevent any downward movement of the flipper 1074 during the operation of the handheld device 1000. In some configurations, the flipper 1074 may include two connected components, such as two brass components brazed together. The main function of the flipper 1074 is to Figure 4EThe needle top plate 1112 is held in place. Subsequently, during the remaining normal operation, the flipper 1074 moves outside the needle top plate 1112. In some configurations, the flipper mounting block 1066 can be used as Figure 4E a guide for the solenoid plunger rod 1106 (e.g., to maintain proper alignment).

[0052] Still referring to Figures 4A to 4E and in particular Figure 4D , further exemplary details of the horizontal component assembly 1044 according to some configurations are shown. The horizontal component assembly can include sensors, actuators, and / or guides for positioning the horizontal carrier assembly 1082 and thus includes the hammering members 1098a, 1098b for driving the microneedles into the tissue (described below). In some configurations, the horizontal fiducial sensor 1064 can be used to position the horizontal component assembly 1082. As shown, the horizontal component assembly 1044 can include a horizontal carrier assembly 1082 that can be configured to mount the horizontal motor 1050. In some configurations, the horizontal chassis 1084 can support the horizontal carrier assembly 1082. Additionally, the right frame assembly 1040b and the left frame assembly 1040a can be attached, for example using rivets, to opposite sides of the horizontal chassis 1084. According to some configurations, a ground connection 1080 can be attached to the horizontal chassis 1084.

[0053] In some configurations, the horizontal component assembly 1044 can further include a retractable sliding door 1090. When the cartridge 2002 has not been inserted into the engagement slot 1002, the sliding door 1090 can extend across the loading hole 1006. Thus, the user can be prevented from putting anything into the handheld device 1000 when there is no cartridge 2002. The sliding door 1090 can be fixed to the sliding door mounting portion 1086, and the sliding door mounting portion 1086 can be attached to the horizontal chassis 1084. Additionally, the sliding door spring 1088 can be fixed to the sliding door mounting portion 1086 and biased such that the sliding door 1090 remains in the "closed" position (i.e., extends across the loading hole 1006) when no cartridge is loaded.

[0054] As shown, according to some configurations, the horizontal carrier assembly 1082 may include strikers 1098a, 1098b, corresponding striker return springs 1092a, 1092b, and corresponding striker guides 1094a, 1094b. Generally, the horizontal carrier assembly 1082 may be configured to position and guide the strikers 1098a, 1098b to drive the microneedles into the tissue. In some configurations, the striker guides 1094a, 1094b may be made of bronze, which helps maintain the bearing surfaces over many pick-up and dispense cycles. Additionally, in some configurations, the strikers 1098a, 1098b may be hardened 17-4 stainless steel, which can provide excellent wear characteristics while maintaining anti-corrosion properties. Alternatively, the strikers 1098a, 1098b may be different load-bearing materials. The horizontal carrier assembly 1082 may further include a horizontal lead screw drive nut 1096. Additionally, the horizontal lead screw assembly 1096 may be a Teflon-coated lead screw and an acetal drive nut designed to reduce friction. Alternatively, the horizontal lead screw assembly 1096 may include other material types. The horizontal lead screw assembly 1096 may provide a pitch sufficient to meet the positioning resolution and linear force. The horizontal carrier assembly 1082 may additionally use motor stall to sense whether a cartridge has been loaded or if there is a device jam.

[0055] Still referring to Figures 4A to 4E , and in particular Figure 4E , further exemplary details of the vertical component assembly 1046 according to some configurations are shown. As shown, the vertical component assembly 1046 may include a solenoid 1052 and a corresponding solenoid plunger rod 1106. Additionally, the vertical component assembly 1046 may include a vertical motor 1100, corresponding unlocking cams 1102a, 1102b, and vertical lead screws 1104a, 1104b. In some configurations, the vertical position of the vertical carrier subassembly 1108 may be controlled by traveling up and down on the vertical lead screws 1104a, 1104b (e.g., using the vertical motor 1100). As will be described, the vertical positioning may move each microneedle corresponding to the cartridge 2002. Generally, the vertical component assembly 1046 may be configured to interface with and manipulate the cartridge 2002 and its associated components during pick-up and / or dispense of the tissue. In some configurations, the vertical motor 1100 is sized to fit within the vertical component assembly 1046 while still providing the torque and speed required to manipulate the microneedle positions.

[0056] In some configurations, the solenoid 1052 can deliver an operating force to the strikers 1098a, 1098b during retraction. As a non-limiting example, the solenoid 1052 can be activated by a half-wave alternating current. The force delivered by the solenoid 1052 increases sharply near the end of its stroke. In some configurations, the mass of the solenoid plunger rod 1106 and the solenoid plunger can be selected based on the energy required to drive the microneedles into the tissue. In some configurations, a stop (such as a brass stop) can be integrated into the solenoid 1052, which can enable extension control of the solenoid plunger rod 1106 and absorb the remaining kinetic energy at the end of the stroke.

[0057] In some configurations, the vertical component assembly 1046 can include a vertical carrier assembly 1108. As shown, the vertical carrier assembly 1108 can include a needle retraction slider 1110 with a top plate 1112. In some configurations, the opposite ends of the vertical carrier assembly 1108 can include needle retraction slide latches 1116a, 1116b with corresponding latch plates 1122a, 1122b. The latch plates 1122a, 1122b can define the maximum position of the needle retraction slider 1110. Additionally, a needle retraction spring 1120 can be integrated into the vertical carrier assembly 1108, enabling effective retraction of the microneedles onto the pins. The needle retraction slide latches 1116a, 1116b can be used to lock the needle retraction slider 1110 in preparation for retraction. The vertical carrier assembly 1108 can also move the needle and the pins (such as the pins within the microneedles) simultaneously.

[0058] In some configurations, the vertical carrier assembly 1108 can include a cartridge latch 1114, which can be configured to secure the cartridge 2002 when inserted into the loading aperture 1006. Additionally, according to some configurations, a vertical indicator 1118 can be attached to the exterior of the vertical carrier assembly 1108. As shown, the needle retraction slider 1110 can also include guide rods 1124a, 1124b, which can be configured to guide the needle retraction slider 1110 during vertical movement. In some configurations, the needle retraction slider 1110 can include a locking latch 1126, which can contact the guide rods 1124a, 1124b and is configured to engage and disengage the microneedles during operation of the handheld device 1000. The needle retraction slider 1110 can be a spring-loaded subassembly with at least two functions. First, the slider 1110 can lock the needle module (after driving into the tissue). Second, the slider 1110 can retract the needle. In some configurations, the needle retraction slider 1110 can only retract the needle and cannot move the needle forward. Additionally, in some configurations, the locking latch 1126 can only function after the skin grafting system 3000 has been initialized. Further details regarding the skin grafting system 3000 are provided below.

[0059] Now refer to Figures 5A to 5B, shows cartridge 2002 and cartridge assembly 2000 according to some configurations. As shown, cartridge assembly 2000 may include cartridge 2002 and cartridge lid 2004, and cartridge lid 2004 may be removably attached to microneedle chamber 2018. Microneedle chamber 2018 may enclose a plurality of microneedles 2006. In some configurations, microneedles 2006 may be arranged in an array within microneedle chamber 2018. As Figure 5A shown, the combination of cartridge lid 2004 and microneedle chamber 2018 may form a housing for microneedles 2006. Cartridge lid 2004 may include release levers 2016a, 2016b, which a user may press simultaneously to remove cartridge lid 2004 from cartridge 2002.

[0060] In some configurations, cartridge 2002 may include tissue stabilizer 2014, which forms an outer peripheral housing and may be configured to stabilize tissue during harvesting. That is, tissue stabilizer 2014 forms an outer peripheral housing that is wider than microneedle chamber 2018, allowing for greater force distribution during use of skin grafting system 3000 on tissue. As shown, tissue stabilizer 2014 may also include outwardly extending loading tabs 2012a, 2012b. In some configurations, during loading of cartridge assembly 2000 into loading hole 1006, loading tabs 2012a, 2012b slide into contact with engagement slots 1002.

[0061] Now referring to Figures 6A to 6C , shows microneedles 2050 and microneedle array 2006 according to configurations of the present disclosure. Microneedles 2050 may assist in harvesting tissue from a donor site. In some configurations, microneedles 2050 may include hollow tube 2054, which may include a plurality of points 2056 at its distal end. In some non-limiting examples, needle systems such as those described in U.S. Patent Nos. 9,060,803, 9,827,006, 9,895,162; and U.S. Patent Application Publication Nos. 2015 / 0216545, 2016 / 0015416, 2018 / 0036029, 2018 / 0140316 may be used and / or combinations or components thereof.

[0062] In some configurations of the present disclosure, hollow tube 2054 may be provided with two points 2056, which may be angled sufficiently to penetrate and cut biological tissue, thereby removing small micrografts from the biological tissue. Such a hollow tube 2054 may be provided with two points 2056, and a "narrow heel" portion located between the two points 2056. According to some embodiments, the narrow heel portion may be made sharp to form a cutting edge corresponding to hollow tube 2054.

[0063] In some configurations, the hollow tube 2054 may be slidably attached to the substrate 2058 such that the hollow tube 2054 can pass through a hole provided in the substrate 2058, as Figure 6A shown. The position of the hollow tube 2054 relative to the substrate 2058 can be controlled by translating the hollow tube 2054 relative to the substrate 2058, e.g., substantially along the longitudinal axis of the hollow tube 2054. In this way, the distance by which the distal end of the hollow tube 2054 projects beyond the lower surface of the substrate 2058 can be controllably changed.

[0064] The microneedle 2050 may also include a pin 2052 disposed in the central lumen or opening of the hollow tube 2054. The diameter of the pin 2052 may be substantially the same as or slightly smaller than the inner diameter of the hollow tube 2054 such that the hollow tube 2054 can be translated along the axis corresponding to the pin 2052 while the pin 2052 fills or occludes most or all of the lumen of the hollow tube 2054. The pin 2052 may be formed of a low-friction material or coated with a low-friction material such as or the like to facilitate movement of the hollow tube 2054 relative to the pin 2052 and / or inhibit accumulation or adhesion of biological materials to the pin 2052. The distal end of the pin 2052 may be substantially flat to facilitate displacement of the tissue micro-graft within the hollow tube 2054 when the hollow tube 2054 is translated relative to the pin 2052.

[0065] The hollow tube 2054 can be translated relative to the pin 2052, e.g., substantially along the longitudinal axis of the hollow tube 2054. In this way, the position of the distal end of the hollow tube 2054 relative to the distal end of the pin 2052 can be controllably changed. For example, the positions of the distal ends of both the hollow tube 2054 and the pin 2052 can be controllably and independently selected and changed relative to the position of the lower surface of the substrate 2058.

[0066] Figure 6B One configuration of the present disclosure is shown in which the pin 2052 can be positioned relative to the hollow tube 2054 such that the distal ends of both are substantially aligned. In another configuration, the pin 2052 can extend slightly beyond the distal end of the hollow tube 2054 such that the sharp portion of the hollow tube 2054 can be shielded from undesired contact with objects and / or the user. Optionally, portions of the pin 2052 and / or the hollow tube 2054 can be provided with a coating or surface treatment to reduce friction between them and / or between any of the components or biological tissue.

[0067] As described herein, a plurality of microneedles (e.g., microneedle 2050) can form a microneedle array 2006. Figure 6CA top view of an exemplary microneedle array 2006 constructed in accordance with the present disclosure is shown. In some configurations, the microneedle array 2006 can be substantially circular. The microneedle array 2006 can be formed by assembling multiple rows of needles (horizontal rows or vertical rows). The design can be modular, and the configuration can take any shape or size using rows of various sizes as modules. In some configurations, all microneedles can be actuated simultaneously, such as inserted into tissue. In other configurations, multiple groups or segments can be actuated sequentially. For example, the microneedle array 2006 can be divided into multiple quadrants, and each quadrant can be actuated sequentially. Sequentially can refer to actuating each row in a linear order (such as row 1, row 2, row 3) or a non-linear order (such as row 1, row 10, row 3). Alternatively, each row of microneedles can be actuated individually and sequentially. In addition, each individual microneedle can be actuated individually and sequentially. In some configurations, one row can be actuated at a time. For example, 20 rows can be actuated individually in sequence, while in other configurations, two rows, three rows, four rows, or more rows can be actuated at a time. The advantage of sequentially actuating segments of the microneedle array 2006 is that the force required for the insertion segment at the donor site is less than the force required for inserting the entire microneedle array 2006. In some configurations, a solenoid (such as solenoid 1052) can be used to drive the microneedle array 2006. Multiple actuations using the solenoid can be inserted row by row sequentially.

[0068] Now refer to Figure 7, some non - limiting examples of the steps of a process 4000 for harvesting and dispensing tissue according to the construction of the present disclosure are shown. In some constructions, as described above, the skin grafting system 3000 can be used to implement the process 4000. As shown, the process 4000 includes powering the handheld device (process block 4002). In some constructions, the handheld device can be the same as or similar to the handheld device 1000. The process 4000 shown also includes loading a cartridge into the handheld device (process block 4004). In some constructions, the cartridge can be the same as or similar to the cartridge 2002 or the cartridge assembly 2000. Further, the process 4000 is shown as including activating a harvesting mode (process block 4006). According to some constructions, this activation can be initiated via the user interface 1008, as will be described below. Alternatively, this activation can be initiated by contacting the donor site. The process 4000 is shown as including applying a skin grafting system (e.g., the skin grafting system 3000) to the donor site (process block 4008). The donor site can correspond to a healthy area of the patient's tissue. Next, the process 4000 is shown as including initiating a harvesting process (process block 4010). In some constructions, this initiation can be via the above - mentioned trigger 1014. The process 4000 is shown as also including removing the skin grafting system from the donor site (method block 4012). Next, the process 4000 is shown as including activating a dispensing mode (process block 4014). In some constructions, this activation can be via the user interface 1008, as described below. The process 4000 is shown as also including positioning the skin grafting system above the recipient site (process block 4016). In some constructions, the recipient site can correspond to a damaged area of the patient's tissue. Next, the process 4000 is shown as including initiating a dispensing process (process block 4018). In some constructions, this initiation can be via actuating the above - mentioned trigger 1014. As shown, the process 4000 can end after the dispensing process (process block 4018), or can return to process block 4006 to re - activate the harvesting mode. In some constructions, a single cartridge (e.g., the cartridge 2002) can be used multiple times on the same patient. Advantageously, if the recipient site is relatively large, a single cartridge can be used for multiple harvestings and dispensings. Thus, the process 4000 can continue with process blocks 4006 to 4018 until the user is ready to dispose of the cartridge.

[0069] According to the construction of the present invention, the skin grafting system 3000 can be used to perform the harvesting process and the dispensing process. Thus, a non - limiting description of the internal functions of the handheld device 1000 and the cartridge 2002 is disclosed herein.

[0070] User interface

[0071] Reference Figure 2B, as a non - limiting example, an example of using the user interface 1008 to control the above - mentioned process is provided. When powering the handheld device, when the handheld device 1000 is first powered on (for example, about 8 seconds at initial startup), the preparation input unit 1018 may flash green. This can notify the user that the handheld device 1000 is performing a startup self - check or other operations. As another non - limiting example, the preparation input unit 1018 may produce a stable green illumination when the handheld device 1000 is turned on and ready for subsequent use. In some configurations, pressing the preparation input unit 1018 for a predetermined amount of time (e.g., 3 seconds, 5 seconds, etc.) may cause the handheld device 1000 to enter the standby mode. Continuing this non - limiting example, when the handheld device 1000 is in the standby mode, the preparation input unit 1018 may stop emitting light. Other light colors, patterns, and timings can be implemented according to various configurations and preferences.

[0072] As another non - limiting example, as will be described in the skin grafting process, when the handheld device 1000 is in the collection mode but has not reached sufficient pressure against the donor site, the indicator light 1020 may emit a stable white light. Additionally, when the handheld device 1000 is in the collection mode and has reached sufficient pressure against the donor site (and the trigger 1014 is disengaged), the indicator light 1020 may emit a stable green light. When the handheld device 1000 is in the collection process, the indicator light 1020 may emit a flashing green light. If during the collection process, the pressure drops below the threshold, the indicator light 1020 may emit a flashing white light. Additionally, when the handheld device 1000 experiences a fault condition, the indicator light 1020 may emit a flashing white light.

[0073] In another non - limiting example, when the collection process is completed, the dispensing input unit 1022 may emit a stable white light. In some configurations, subsequently pressing the dispensing input unit 1022 may cause the handheld device 1000 to enter the dispensing mode. When the handheld device 1000 is in the dispensing mode, the dispensing input unit 1022 may emit a stable green light. Similar to the indicator light 1020, when the handheld device 1000 experiences a fault condition, the dispensing input unit 1020 may emit a flashing white light. In some configurations, the dispensing input unit 1022 may emit a flashing white light during the collection process, which may indicate that a draw - back recovery is needed. Subsequently pressing the dispensing input unit 1022 may activate the draw - back recovery process. Once the draw - back recovery process is completed, the dispensing input unit 1022 may emit a stable white light. The draw - back recovery process is described in detail below.

[0074] In some configurations, similar to the indicator light 1020, when the handheld device 1000 is in the collection mode and has reached sufficient pressure against the donor site (and the trigger 1014 is disengaged), the indicator light 1016 may emit a continuous green light. Additionally, according to some configurations, the indicator light 1020 may emit a flashing green light during the collection process.

[0075] Operating positions of the skin grafting system

[0076] In some configurations, multiple operating positions corresponding to the skin grafting system 3000 may be defined. Notably, the skin grafting system 3000 may operate using additional operating positions that are not explicitly defined.

[0077] Some configurations of the present disclosure include a horizontal carrier original position, where the horizontal carrier assembly 1082 may be in a position that obscures the horizontal flag sensor 1064. This position may be a "safe" position that keeps the carrier away from other moving parts.

[0078] Some configurations of the present disclosure include a vertical carrier original position corresponding to a calibration position, where the vertical carrier assembly 1108 may be aligned with corresponding components for loading or unloading. This position may be below the vertical flag sensor occlusion point. From the user's perspective, the vertical carrier assembly 1108 may appear to be closest to the engagement slot 1002 of the handheld device 1000.

[0079] Some configurations of the present disclosure include a vertical carrier unlock / spread position corresponding to a calibration position, where the vertical carrier assembly 1108 unlocks the needle retraction slider 1110 by pushing the needle retraction sliding latches 1116a, 1116b above their respective unlocking cams 1102a, 1102b. This may be the highest position that the vertical carrier assembly 1108 will travel to. From the user's perspective, the vertical carrier assembly 1108 may appear to be standing upright inside the handheld device 1000.

[0080] Some configurations of the present disclosure include a "flipper in" position and a "flipper out" position. Each flipper 1074 may have two defined positions, which the handheld device 1000 detects via flag sensors that can provide positive feedback of having reached each position. The "flipper in" or retracted position may correspond to when the flipper 1074 is safely away from moving parts. The "flipper out" or extended position may correspond to when the flipper 1074 blocks the top plate 1112. The "flipper out" position may be used for initialization when the needle retraction slider 1110 (and thus the cartridge 2002) is locked.

[0081] Some configurations of the present disclosure include a vertical carrier locking position corresponding to a calibration position, to which the vertical carrier assembly 1108 may be moved (with the flipper 1074 extended therewith) to compress the needle retraction spring 1120 and lock the needle retraction sliding latch 1116. This "locking" may allow the needle to be retracted later, while also locking the cartridge 2002 inside the handheld device 1000.

[0082] Some configurations of the present disclosure include a vertical carrier lock release position, which may be a position offset from the calibrated lock position, where the correctly locked needle retracting sliding top plate 1112 will no longer exert pressure on the flipper 1074, so that the flipper 1074 can be safely retracted. Conversely, if the needle retracting sliding top plate 1112 is not correctly locked, this position can be designed to maintain sufficient pressure on the flipper 1074 such that these flippers do not retract. This position enables the handheld device 1000 to clearly sense the correct locking of the needle retracting slider 1110.

[0083] Some configurations of the present disclosure include a vertical carrier extraction position, which may be a position offset from the calibrated unlock position, where the needle retracting slider 1110 will not be unlocked and the extended needle can be behind the tissue stabilizer 2014. After collection, this is the position where the vertical carrier assembly 1108 can withdraw the needle (including the tissue graft) from the tissue before dissemination. Advantageously, since the needle remains extended, the tissue graft can be exposed in this position.

[0084] Some configurations of the present disclosure include a collection recovery mode, which may occur during collection. The collection recovery mode may include an attempt to continue deploying the needle module into the tissue. Additionally, the collection recovery mode can be automatic and fully controlled by on-board software (i.e., without user interaction). In some embodiments, the collection recovery mode may include reversing the movement of the horizontal carrier assembly 1082 by a predetermined distance or time interval. Subsequently, the horizontal carrier assembly 1082 can advance and attempt to deploy the needle head module into the tissue again.

[0085] Some configurations of the present disclosure include an extraction recovery mode, which may occur after the needle has been deployed (and the handheld device 1000 is attempting to return the horizontal carrier to its original position). In some configurations, due to increased friction from the needle module, the horizontal carrier assembly 1082 may become stuck. If this occurs, the handheld device 1000 can cause the dissemination light (on the dissemination input 1022) to flash white, indicating that extraction recovery is needed. Then, the user can relieve the downward force on the tissue and press the dissemination input 1022, which will allow the handheld device 1000 to continue withdrawing the needle from the tissue.

[0086] Vertical operation of the skin graft assembly

[0087] According to some configurations, various components corresponding to the handheld device 1000 and the cartridge 2002 can have predefined operations based on the current mode of the handheld device 1000 (e.g., initialization, collection mode, dissemination mode, etc.).

[0088] In some configurations, the vertical component assembly 1046 can have a pre - defined "loading" configuration that corresponds to loading the cartridge 2002 into the handheld device 1000. For example, during loading, the solenoid plunger rod 1106, each flipper 1074, and the needle retraction slider 1110 (retracting the needle) can be retracted. The vertical carrier assembly 1108 can be set to the original position (as described above).

[0089] In some configurations, the vertical component assembly 1046 can have a pre - defined "initialization" configuration. For example, during initialization, each flipper 1074 can be extended (flipper out), the needle retraction slider 1110 can be locked, and the needle retraction spring 1120 is loaded (the needle remains retracted). The vertical carrier assembly 1108 can be set to the locked position (as described above). When each flipper 1074 extends, the vertical carrier assembly 1108 can move upward to the locked position. The extended flipper 1074 can hold the needle retraction slider 1110 in place. When the vertical carrier assembly 1108 reaches the locked position, the needle retraction slide latch 1116 can lock the top plate 1112 in place and the needle retraction spring 1120 is loaded. In some configurations, this does not move the needle from its retracted state.

[0090] In some configurations, the vertical component assembly 1046 can have a pre - defined "initialized" configuration that can correspond to the skin grafting system 3000 being ready to receive. For example, in the initialized configuration, each flipper 1074 can be retracted (flipper in), the needle retraction slider 1110 can be locked, and the needle retraction spring 1120 is loaded. In some configurations, this does not move the needle from its retracted state. According to some configurations, the vertical carrier assembly 1108 can move downward back to the original position.

[0091] In some configurations, the vertical component assembly 1046 can have a pre - defined "receiving" configuration corresponding to the applied user force. For example, in the receiving configuration, the needle retraction slider 1110 can remain locked, and the needle retraction spring 1120 is loaded and the needle retracts. According to some configurations, the vertical carrier assembly 1108 can remain in the receiving position. When the user positions the skin grafting system 3000 at the donor site and applies a downward force, the user will perceive that the tissue stabilizer 2014 moves slightly in the direction opposite to the applied force, causing the indicator light 1016 and the indicator light 1020 to illuminate, indicating to the user that there is a correct receiving alignment. In some configurations, the indicator light 1016 can illuminate green to provide the user with a visual confirmation of the force.

[0092] In some configurations, the vertical component assembly 1046 may have a predefined "retrieving" configuration corresponding to needle deployment. For example, in this retrieving configuration, the solenoid plunger rod 1106 may be advanced, and the needle retraction slider 1110 may be held locked, and the needle retraction spring 1120 may be loaded. Notably, the needle (e.g., a needle from the microneedle array 2006) may be deployed into the tissue. According to some configurations, the vertical carrier assembly 1108 may be held in the original position, and a user force may still be applied via the handheld device 1000. When the user pulls the trigger 1014, the skin grafting assembly 3000 may begin the retrieving sequence. Thus, the skin grafting assembly 3000 may cause each row of needles in the microneedle array to advance into the tissue by striking the strikers 1098a, 1098b with the solenoid plunger rod 1106.

[0093] In some configurations, the vertical component assembly 1046 may have a predefined "withdrawing" configuration. For example, in this withdrawing configuration, the solenoid plunger rod 1106 may be retracted, and the needle retraction slider 1110 may be held locked, and the needle retraction spring 1120 may be loaded. The needle (e.g., from the microneedle array 2006) may remain deployed into the tissue at the start of the withdrawal. The vertical carrier assembly 1108 may be moved to the withdrawal position (as described above). In some configurations, after the retrieving is complete, the skin grafting system 3000 may withdraw the needles by lifting all the needles within the microneedle array 2006 at once. The needles may be lifted to the withdrawal position, and the user force may be removed. In some configurations, the needles may remain advanced relative to the pins (e.g., pin 2052), and the tissue stabilizer 2014 may remain stationary when the needles are retracted.

[0094] In some configurations, the vertical component assembly 1046 may have a predefined "dispensing" configuration. For example, in the dispensing configuration, the needle retraction slider 1110 may be in the retracted position, and the needles may be similarly retracted. In some configurations, the vertical carrier assembly 1108 may be moved from the withdrawal position. When the user activates the dispensing sequence, the skin grafting system 3000 may move the vertical carrier assembly 1108 from the extraction position, which may release the loaded needle retraction spring 1120 and the needle retraction slider 1110. Thus, this movement may retract the needles relative to the pins (e.g., pin 2052), thereby exposing the graft and positioning the components for the dispensing sequence.

[0095] In some configurations, the vertical component assembly 1046 may have a "dispensing" configuration corresponding to the forward needle position. For example, in this dispensing configuration, the solenoid plunger rod 1106 may advance, and the needle retraction slider 1110 may advance (similarly, the needle may advance). According to some configurations, the solenoid plunger rod 1106 may advance, first hitting the top plate 1112, and then hitting the needle module (e.g., within the microneedle array 2006). This may push the top plate 1112 in front of the needle carrier, thus preventing damage to the carrier. The needles advance, and subsequently (through the unlocked top plate 1112), quickly retract these needles, which may disperse the graft into the recipient site.

[0096] Power-on self-test

[0097] In some configurations, the handheld device 1000 may perform a self-test upon startup (e.g., when the handheld device 1000 is first powered on). In some configurations, when the handheld device 100 is inserted to receive power and the ready input section 1018 is pressed and released, a self-test may be performed. According to some configurations, the ready input section 1018 may flash green during the entire self-test. Next, the horizontal carrier assembly 1082 may move forward a very small amount, thus moving away from the horizontal flag sensor 1064. Subsequently, the horizontal carrier assembly 1082 may return to its original position.

[0098] During the self-test, the vertical carrier assembly 1108 may move upward a very small amount such that the vertical flag 1118 moves away from the sensor. Subsequently, the vertical carrier assembly 1108 may return to its original position. In some configurations, the vertical carrier assembly 1108 may move upward to an unlocked position, and before returning to its original position, the needle retraction slide latch 1116 may be moved at the unlocked position. For example, if the needle retraction slider 1110 is locked (e.g., the cartridge 2002 is locked), the needle retraction slider 1110 may be released.

[0099] In some configurations, the horizontal carrier assembly 1082 may move to a predetermined position (e.g., approximately two-thirds of the entire range), which may verify the absence of a cartridge (e.g., the cartridge 2002). Subsequently, the horizontal carrier assembly 1082 may return to its original position.

[0100] During the self-test, the flipper 1074 may extend and then retract. Additionally, in some configurations, some or all of the lights on the handheld device 1000 may flash (e.g., the indicator lights 1016, 1020, the dispensing input section 1022, etc.). After completing the self-test, the ready input section 1018 may light up with a steady green, which may indicate, for example, that the self-test was successful.

[0101] Loading and initializing the cartridge

[0102] In some configurations, the skin grafting system 3000 can have a pre - defined cartridge loading and initialization process. The user can open the loading door 1004 and then slide the cartridge assembly 2000 (i.e., including the cartridge lid 2004) into the engagement slot 1002. The cartridge latch 1114 can lock onto the cartridge 2002. Then, the user can remove the cartridge lid 2004 and close the loading door 1004, which can activate the internal loading door switch.

[0103] The initialization process can also include moving the horizontal carrier assembly 1082 from its original position so that it can detect the presence of the cartridge by pausing over the first cartridge segment. Subsequently, the horizontal carrier assembly 1082 can return to its original position. Additionally, the vertical carrier assembly 1108 can move a small amount so that the vertical marker 1118 moves away from the sensor, and then the vertical carrier assembly 1108 can return to its original position.

[0104] In some configurations, the flipper 1074 can extend above the top plate 1112. The vertical carrier assembly 1108 can move to the locking position. When moved to the locking position, the flipper 1074 can hold the top plate 1112 in place while the needle retraction slide latch 1116 moves out and finally locks onto the top plate 1112. Thus, the needle retraction spring 1120 can be held in a compressed state. For example, when this occurs, the locking latch 1126 can pop out under the needle segment (e.g., the needle segment within the microneedle array 2006) to prepare to lock the needle segment during the retraction sequence. In some configurations, the vertical carrier assembly can move down a small amount and thus move into the (as described above) locking release position. Additionally, the flipper 1074 can retract.

[0105] The initialization process can also include returning the vertical carrier assembly 1108 to the retraction position. The horizontal carrier assembly 1082 can engage the first needle segment by pausing against the first needle segment (within the microneedle array 2006) and then backing up a pre - determined small distance. Then the handheld device 1000 can calculate the position of each needle segment. After the initialization process is complete, the indicator light 1020 can turn white to indicate that the handheld device 1000 is ready for the retraction sequence.

[0106] Retraction and Extraction Methods

[0107] In some configurations, the user can use the harvesting process to harvest and withdraw tissue columns. The user can position the handheld device 1000 at the donor site and press the tissue stabilizer 2014 against the skin. The user can apply force to the skin via the handheld device 1000 with one or both hands. The tissue stabilizer interface component can move upward, compressing the position sensing spring 1056 until the position sensing marker 1062 obscures the marker sensor. In some configurations, the indicator lights 1016, 1020 can illuminate green, indicating that the trigger 1014 is operative.

[0108] Once the trigger 1014 is operative, the user can pull the trigger 1014 (while maintaining force on the skin), and the handheld device 1000 can begin the harvesting sequence. In some configurations, the indicator lights 1016, 1020 can flash green during the entire harvesting and withdrawal. The position sensing marker 1062 can be monitored throughout the harvesting (between solenoid activations) to ensure sufficient force is maintained. The solenoid 1052 can rapidly advance the solenoid plunger rod 1106, which can advance the two striker pieces 1098a, 1098b and insert the first needle module into the tissue. When inserting the needle module, the needle module travels past the needle module locking latch. Subsequently, the solenoid 1052 and the striker pieces 1098a, 1098b can retract, and the needle segment can remain locked in the tissue.

[0109] In some configurations, the horizontal carriage assembly 1082 can advance to the calculated next needle segment position. Alternatively, during the entire harvesting process, the next needle segment position can be recalculated or otherwise re-verified. The solenoid 1052 can rapidly advance the solenoid plunger rod 1106, which can advance the two striker pieces 1098a, 1098b and insert the next needle module into the tissue. When inserting the needle module, the needle module can travel past the locking latch 1126. The locking latch 1126 can snap back, and the solenoid 1052 and the striker pieces 1098a, 1098b can retract. This insertion process can be repeated until all needle segments are inserted into the tissue.

[0110] According to some configurations, after all segments are inserted, the horizontal carriage assembly 1082 can return to its original position. The vertical carriage assembly 1108 can move upward to the withdrawal position, withdraw the needle from the tissue, and position the needle to stand safely within the tissue stabilizer 2014. The indicator lights 1016, 1020 can stop flashing green and turn off. Additionally, the dispensing input 1022 can illuminate white, indicating that the handheld device 1000 is ready for the dispensing process. After the harvesting process is complete, the user can remove the force on the tissue and lift off the handheld device 1000.

[0111] Dispensing method

[0112] In some configurations, the user may disperse the tissue column after collection. Once the user removes the handheld device 1000 (with the collected tissue column) from the donor site, the needle can be safely erected within the cassette 2002 (e.g., within the tissue stabilizer 2014). When the recipient site is prepared for the tissue column, the user can activate the dispersion mode by pressing the dispersion input 1022. In some configurations, the dispersion input 1022 may change from lit white to green.

[0113] In some configurations, the user may position the cassette 2002 directly above the recipient site. Then, the user can pull the trigger 1014, and the vertical carrier assembly 1108 can move out of the retracted position, which can release the needle retraction slider 1110 and move it behind the needle retraction pin (e.g., pin 2052). The handheld device 1000 can rapidly advance the solenoid plunger rod 1106, thereby pushing the needle retraction slider 1110 and the needle module. The needle retraction slider 1110 can be kept pushed in front of the needle module to prevent damage to the needle module. Subsequently, the solenoid plunger rod 1106 can retract, which causes the needle retraction slider 1110 to retract (pulling back the needle module with the needle retraction slider 1110). The process of rapidly advancing the solenoid plunger rod 1106 can be repeated several times, which can ensure that as much graft as possible is deposited into the recipient site. In some configurations, the solenoid 1052 may be activated six times. After the dispersion process is complete, the vertical carrier assembly 1108 can return to its original position, and the needle retraction slider 1110 is unlocked.

[0114] Removing the Cassette

[0115] In some configurations, once the user has completed the collection and dispersion processes, the user can open the loading door 1004, press the cassette latch 1114, and slide out the cassette 2002. In some configurations, if the user wishes to perform another collection with the same cassette 2002, the user can open and close the loading door 1004 (i.e., without removing the cassette 2002). This can start another initialization process via the handheld device 1000. Alternatively, the user can start another initialization process via an input (not shown) on the user interface 1008.

[0116] Fluid Ingress Protection

[0117] As described above, prior to removal from and subsequent disposal of the handheld device 1000, the cartridge 2002 can be used for multiple pick-up and dispense processes (for a single patient). In some cases, repeated puncturing of tissue via the microneedle array 2006 may result in local bleeding. Additionally, repeated deployment and retraction of the needle module may cause blood or other fluids to disperse. Since the cartridge 2002 can be disposable, blood dispersion outside, for example, the microneedle chamber 2018 may be inconsequential. However, the handheld device 1000 can be reused. Thus, it may be advantageous to prevent blood from entering the housing 1036. For example, if blood penetrates the housing 1036, extensive cleaning and disinfection processes may be required.

[0118] The present disclosure includes systems and methods for preventing blood entry. Specifically, the present disclosure provides a device shield that can protect the contact points (e.g., see Figure 1 ) that exist between the engagement slot 1002 and the cartridge 2002. Additionally, the device shield of the present disclosure can be designed to protect the contact points (e.g., see Figure 1 ) that exist between the loading door 1004 and the cartridge 2002.

[0119] Now referring to Figures 8 to 9 , a device shield 5000 constructed in accordance with the present disclosure is shown. Generally, the device shield 5000 can be configured to removably protect the contact points between the cartridge 2002 and the handheld device 1000. The device shield 5000 is formed from a liquid-impermeable material (or materials) and extends from an inner opening 5002 to an outer edge 5004. At the outer edge, corner cutouts 5006 may be included. Thus, as will be described, the device shield 5000 forms a barrier to fluids surrounding or encircling the inner opening 5002.

[0120] The opening 5002 can engage the microneedle chamber 2018. In this manner, when the cartridge 2002 is engaged with the handheld device 100, the device shield 5000 extends from the opening 5002 above the handheld device 1000 to the outer edge 5004. In some configurations, a portion of the outer edge 5004 can contact the loading door 1004 (e.g., see Figure 9 ). The loading door 1004 can optionally include finger engagement portions 1005 (as shown in Figure 9 ) that can contact a portion of the outer edge 5004. As shown, the finger engagement portions 1005 can extend beyond the device shield 5000 such that the loading door 1004 can be opened and closed even when the device shield 5000 is in place on the skin graft assembly 3000.

[0121] In some configurations, the device shroud 5000 may include corner cutouts (e.g., corner cutout 5006). As an example, the corner cutout 5006 may be inverted and / or rounded so that a user can easily grasp the device shroud 5000 during application of the device shroud 5000 and removal of the device shroud 5000 from the skin graft assembly 3000.

[0122] In some configurations, the device shroud 5000 may extend from the outer peripheral edge of the tissue stabilizer 2014. The device shroud 5000 prevents blood from flowing onto or into the handheld device 1000 by, for example, protecting or sealing any openings corresponding to the engagement slot 1002 that contacts the cartridge 2002 and the loading door 1004 that contacts the cartridge 2002.

[0123] According to some configurations, the device shroud 5000 may be formed of a polymer that forms a barrier to fluids. Additionally, the device shroud 5000 may be formed of a flexible or elastomeric material. The device shroud 5000 may have a generally flat geometry. By having a generally flat geometry and being formed of a flexible or elastomeric material, the size of the device shroud opening 5002 can be designed to be smaller than the outer peripheral size of the microneedle chamber 2018 so that the device shroud 5000 can be stretched over the microneedle chamber 2018. Stretching of the device shroud 5000 can form a seal that is designed to be impermeable to blood and other fluids that typically impinge on the device shroud 5000, thereby preventing liquid from entering the handheld device 1000 along the tissue stabilizer 2014.

[0124] In Figure 9 In the non - limiting example shown, when the opening 5002 of the device shroud 5000 is pulled down the tissue stabilizer 2014, the outer edge 5004 can be pulled and, depending on the material selection and design, stretched away from the opening 5002 to extend toward the handheld device 1000. In this configuration, the device shroud 5000 is no longer in its default, generally flat geometry and presents a ramp or curved surface 5008 extending from the opening 5002 to the outer edge 5004.

[0125] The size of the device shroud 5000 can vary and, in some embodiments, can be customized. As an example, the device shroud 5000 can be cut into different shapes and sizes to customize the prevention of blood entry and the usability of the skin graft assembly 3000. According to some embodiments of the present disclosure, the device shroud 5000 can be molded into a generally fixed shape and / or size. As a non - limiting example, the device shroud 5000 can contact the exterior of the microneedle chamber 2018 (e.g., the tissue stabilizer 2014) and can otherwise extend outward therefrom (e.g., at a 90 - degree angle, a 45 - degree angle, etc.). Thus, the device shroud 5000 can provide a non - contact barrier for the entry point on the housing 1036.

[0126] Reference Figure 10 , shows a vertical cross-sectional view of a non-limiting example of a device shroud 5000 that engages with a tissue stabilizer 2014 and extends to a loading door 1004 and a housing 1036. In this example, the device shroud 5000 has an internal opening 5002 sized to be slightly smaller than or match the exterior of the tissue stabilizer. In this way, by pulling on the outer edge 5004, the device shroud 5000 extends downward over the tissue stabilizer 2014, stretching the device shroud 5000, and in this illustration, causing the inner surface 5010 of the device shroud 5000 to form the internal opening 5002 when in the non-mounted position, extending perpendicular to the inner normal position and the tissue stabilizer. That is, since the internal opening 5002 is sized to match the dimensions of the tissue stabilizer 2014, the opening must stretch and deform to accommodate the degree of extension over the tissue stabilizer 2014, which displaces the inner surface 5010 to the lateral position shown in the illustration.

[0127] In some configurations, the device shroud 5000 can be molded to provide a customized downward seal for the handheld device 1000 (and associated entry points). As a non-limiting example, the device shroud 5000 can be molded to align with the curvature of the tissue stabilizer 2014, the microneedle chamber 2018, and / or the loading door 1004. In Figure 10 the non-limiting example shown, the device shroud is assumed to be recessed oriented, which forms a tight seal with the tissue stabilizer 2014 at the internal opening 5002 and with the housing 1036 and the loading door 1004 at the outer edge 5004. Additionally, the device shroud 5000 can be designed to have a recess 5012 disposed between the device shroud 5000 and the engagement slot 1002. The recess 5012 can be configured to hold absorbent material 5014 that can further prevent blood from entering the handheld device 1000. As shown, the absorbent material 5014 can be arranged in a circular or rectangular shape, which engages and surrounds the tissue stabilizer 2014 and resides in the recess 5012 above the engagement slot 1002. Alternatively, as shown by the dashed line, the absorbent material 5014a can have any of a variety of cross-sectional geometries or thicknesses.

[0128] Although the present disclosure may be susceptible to various modifications and alternative forms, specific configurations have been shown by way of example in the drawings and described in detail herein. However, it should be understood that the present disclosure is not intended to be limited to the particular forms disclosed. Instead, the present disclosure covers all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.

[0129] This written description uses examples to disclose the present disclosure, including the best mode, and also enables those skilled in the art to practice the present disclosure, including making and using any device or system and performing any combined method. The patent scope of the present invention is defined by the claims, and may include other examples that occur to those skilled in the art. If such other examples have structural elements that are not different from the literal language of the claims, or if they include equivalent structural elements that have no substantial difference from the literal language of the claims, then such other examples are intended to be within the scope of the claims.

[0130] Finally, it is specifically contemplated that any processes or steps described herein may be combined, eliminated, or reordered. Accordingly, this description is presented by way of example only and is not otherwise limiting of the scope of the present disclosure.

Claims

1. A skin grafting system, comprising: a cartridge, the cartridge comprising: a plurality of microneedles; and a cartridge housing, the cartridge housing comprising a microneedle chamber, the plurality of microneedles being disposed within the microneedle chamber; a handheld device, the handheld device comprising: a device housing, the device housing defining a loading aperture; and a loading door, the loading door being pivotable between an open position and a closed position; a cartridge latch, the cartridge latch being configured to secure the cartridge when the loading door exposes the loading aperture in the open position and the cartridge is inserted into the loading aperture of the device housing; and wherein the loading door is configured to close over the loading aperture of the handheld device to secure the cartridge; a shield, the shield being configured to prevent fluid from entering the interior of the device housing from around the cartridge housing during a skin grafting procedure using the skin grafting system; and wherein the cartridge housing is configured to be inserted into the loading aperture of the device housing to secure the cartridge to the handheld device.

2. The skin grafting system according to claim 1, wherein: the device housing includes an engagement groove; wherein the cartridge housing is configured to slide into and out of the engagement groove of the device housing; wherein the cartridge housing includes a first loading tab extending outwardly and a second loading tab extending outwardly opposite the first loading tab; and wherein the first loading tab and the second loading tab are configured to slidably contact the engagement groove.

3. The skin grafting system according to claim 1, wherein: further comprising: a cartridge cover, the cartridge cover being removably coupled to the cartridge housing; and wherein the microneedle chamber and the cartridge cover form an enclosure for the plurality of microneedles.

4. The skin grafting system according to claim 1, wherein: the cartridge includes a plurality of pins; and wherein each of the plurality of pins is received within the lumen of a corresponding one of the plurality of microneedles.

5. The skin grafting system according to claim 1, wherein: the handheld device includes a door sensor to determine the position of the loading door.

6. The skin grafting system according to claim 1, wherein: the device housing includes an aperture configured to receive a user's hand; and wherein the handheld device includes a trigger, the trigger being coupled to the device housing at the aperture of the device housing; and wherein the trigger is configured to initiate at least one of a charging process or a dispensing process of the skin grafting system.

7. The skin grafting system according to claim 1, wherein: the plurality of microneedles includes a first set of microneedles and a second set of microneedles; wherein the handheld device is configured to sequentially actuated the first set of microneedles and the second set of microneedles; wherein when the first set of microneedles is actuated, the first set of microneedles extends beyond the cartridge housing to harvest tissue during the skin grafting procedure; and wherein when the second set of microneedles is actuated, the second set of microneedles extends beyond the cartridge housing to harvest tissue during the skin grafting procedure.

8. The skin grafting system according to claim 1, wherein, the shield includes a shield opening; wherein, a part of the cartridge housing can be inserted through the shield opening of the shield; wherein, the shield extends across an opening defined by the engagement between the cartridge housing and the handheld device; and wherein, the opening is at least one of the following openings: an opening formed between the cartridge housing and the handheld device at the loading hole of the device housing; an opening formed between the cartridge housing and the handheld device at the loading door of the handheld device; or an opening formed between the cartridge housing and the handheld device at the engagement groove for receiving the cartridge housing.

9. The skin grafting system according to claim 1, wherein, the shield includes a shield opening; wherein, a part of the cartridge housing can be inserted through the shield opening of the shield; and wherein, when the part of the cartridge passes through the shield opening of the shield, a seal is formed at the shield opening to block the flow of fluid through the shield opening.

10. The skin grafting system according to claim 1, wherein, the shield includes a shielding polymer; and wherein, the shield contacts the exterior of the cartridge housing.

11. The skin grafting system according to claim 1, wherein, the shield is configured to surround the cartridge when the cartridge is fixed to the handheld device.

12. A skin grafting system, comprising: a cartridge, the cartridge including: a plurality of microneedles; a plurality of pins, each of the plurality of pins being received in the lumen of a corresponding one of the plurality of microneedles; a cartridge housing, the cartridge housing including a microneedle chamber in which the plurality of microneedles are arranged; a handheld device, the handheld device including a device housing defining an engagement groove into which the cartridge housing can slide to receive the cartridge; and a shield configured to prevent fluid from entering the interior of the device housing from around the cartridge housing during a skin grafting procedure using the skin grafting system; and wherein, the shield extends across an opening defined by the engagement between the cartridge housing and the handheld device at the engagement groove to block the inflow of fluid into the opening.

13. The skin grafting system according to claim 12, wherein, the plurality of microneedles includes a first group of microneedles and a second group of microneedles; wherein, the handheld device is configured to sequentially actuated the first group of microneedles and the second group of microneedles to harvest tissue; wherein, when the first group of microneedles is actuated, the first group of microneedles extends beyond the cartridge housing to harvest tissue during the skin grafting procedure; and wherein, when the second group of microneedles is actuated, the second group of microneedles extends beyond the cartridge housing to harvest tissue during the skin grafting procedure.

14. The skin grafting system according to claim 13, wherein, the handheld device is configured to sequentially actuated the first group of microneedles and the second group of microneedles to insert the plurality of microneedles into a donor site; Wherein, the handheld device includes a vertical carrier assembly, and the vertical carrier assembly includes one or more needle retraction springs; and Wherein, the one or more needle retraction springs are configured to retract the plurality of microneedles at one time.

15. The skin grafting system according to claim 12, wherein, the handheld device includes a cartridge latch configured to fix the cartridge when the cartridge is inserted into the loading hole of the device housing.

16. A skin grafting system, comprising: a cartridge, the cartridge including: a plurality of microneedles, the plurality of microneedles including a first group of microneedles and a second group of microneedles; and a cartridge housing including a microneedle chamber, and the plurality of microneedles are arranged in the microneedle chamber; a handheld device, the handheld device including: a device housing defining a loading hole; a solenoid configured to drive the first group of microneedles and the second group of microneedles into the skin tissue; a horizontal carrier assembly; and a horizontal motor configured to move the horizontal carrier assembly; and a shield configured to prevent fluid from entering the interior of the device housing from around the cartridge housing during a skin grafting process using the skin grafting system; wherein, the handheld device is configured to sequentially actuated the first group of microneedles and the second group of microneedles; and wherein, the position of the horizontal carrier assembly selects which one of the first group of microneedles or the second group of microneedles enters the skin tissue.

17. The skin grafting system according to claim 16, wherein, during a first actuation of the solenoid, the solenoid is configured to drive the first group of microneedles over the cartridge housing into the skin tissue to harvest skin tissue; wherein, during a second actuation of the solenoid, the solenoid is configured to drive the second group of microneedles over the cartridge housing into the skin tissue to harvest skin tissue; wherein, the horizontal carrier assembly includes a striker configured to drive the first group of microneedles and the second group of microneedles into the skin tissue; wherein, the solenoid is configured to drive the striker so as to drive the first group of microneedles into the skin tissue; and wherein, the solenoid is configured to drive the striker so as to drive the second group of microneedles into the skin tissue.

18. The skin grafting system according to claim 17, wherein, the striker is a first striker; wherein, the horizontal carrier assembly includes a second striker, a first return spring is connected to the first striker, and a second return spring is connected to the second striker; and wherein, during the first actuation of the solenoid, the first group of microneedles is aligned with the first striker and the second striker, and the solenoid forces the first striker and the second striker to drive the first group of microneedles into the skin tissue; and Wherein, during the second actuation of the solenoid, the second set of microneedles is aligned with the first striker and the second striker, and the solenoid forces the first striker and the second striker to drive the second set of microneedles into the skin tissue.

19. The skin grafting system according to claim 16, wherein, the handheld device includes a first locking latch and a second locking latch; wherein, the first locking latch is configured to lock the first set of microneedles into the skin tissue; and wherein, the second locking latch is configured to lock the second set of microneedles into the skin tissue.

20. The skin grafting system according to claim 16, wherein, the handheld device includes a vertical carrier assembly, the vertical carrier assembly includes one or more needle retraction springs; and wherein, the one or more needle retraction springs are configured to retract the plurality of microneedles at once.

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