Micropipette system

Abstract

Provided is a micropipette system with which it is possible for an operator to control suction and discharge of fluid with the same intuitiveness as with an operation by a mouthpiece.　This micropipette system includes: a barrel part having a long axis, a proximal end, and a distal end, the barrel part having a tubular cavity extending along at least a portion of the long axis; a rotatable wheel having a rotation axis within a proximal-side region of the barrel part; a pump member configured to move forward and rearward in the distal direction or the proximal direction within the barrel part in conjunction with rotational movement of the wheel; and a microcapillary needle extending so as to protrude from the barrel part in the proximal direction. The outer edge of the wheel is at least partially exposed from the barrel part. An internal space of the microcapillary needle communicates with the tubular cavity of the barrel part. The forward and rearward movement of the pump member increases or reduces the volume of the tubular cavity, thereby enabling suction or discharge of fluid within the internal space of the microcapillary needle.

Description

Micropipette System

[0001] The present disclosure relates to a micropipette system suitable for delicate manipulation of minute particles such as mammalian ova, fertilized eggs, and early embryos. The micropipette system can be used, for example, in assisted human reproduction, livestock breeding techniques, and laboratory animal reproductive engineering.

[0002] For example, in the fields of assisted reproductive technology (ART) for humans, breeding techniques for livestock such as cattle, and reproductive engineering for laboratory animals such as mice, manipulation of oocytes, fertilized eggs, and early embryos under a microscope is routinely performed. Manipulation here includes fertilization, separation from accompanying materials, sorting, transportation, and transfer of these samples. Assisted reproductive technology, including in vitro fertilization and embryo transfer, is becoming increasingly important in modern society. Similarly, in vitro fertilization is widely used and highly important in the fields of livestock breeding and reproductive engineering for laboratory animals. Needless to say, these techniques require rapid manipulation while handling microliter-order suspension environments without damaging delicate embryos. While successful manipulation of embryos and other materials relies heavily on the skill of the operator, it is also important to continually improve the reliability, safety, and efficiency of manipulation techniques through improvements in equipment and tools.

[0003] In particular, it is desirable to have an operating instrument that can control the introduction and release of fluid through a microcapillary needle according to the "intuition" of an operator observing a suspension of minute embryos or the like under a microscope, and can suck up, move, and dispense the appropriate amount of the appropriate part of the suspension at the appropriate time.

[0004] Traditionally, there are two main methods for manipulating oocytes, fertilized eggs, and early embryos (hereinafter, collectively referred to as "embryo manipulation"): mouthpiece-based and micropipette-based. In the mouthpiece-based method, an operator holds a mouthpiece attached to the other end of a tube with a microcapillary needle at its tip. The operator controls the flow of fluid containing cells, such as embryos, through the microcapillary needle by delicately inhaling and exhaling. The mouthpiece-based method is highly intuitive. This means that it is easier than other methods for operators to inject and exhale the desired amount of fluid at the desired timing. The mouthpiece-based method is the mainstream method for embryo manipulation in Japan, and the present inventor estimates that the majority of human embryo manipulation, as well as almost all embryo manipulation of livestock such as cattle and laboratory animals, is performed using the mouthpiece-based method.

[0005] However, there are some countries where the use of mouthpiece-type instruments is not permitted, for example, in human embryo manipulation, because there is a theoretical possibility that the operator's breath could transmit pathogenic microorganisms, including viruses, to the embryo or other organs, or that the operator, holding the mouthpiece in his or her mouth, could be adversely affected by oral contact.

[0006] U.S. Patent No. 6,299,234 discloses an adjustable pipette. The pipette in U.S. Patent No. 6,299,234 is designed to allow the operator to grip the pipette body with four fingers and the palm of the hand, as if gripping a rod, and to control the intake and discharge of fluid by pushing and pulling a spring-loaded rod protruding distally with the remaining thumb. Such thumb-controlled micropipettes are typically adjustable to allow the operator to aspirate and dispense a precise amount of liquid, as specified in advance by the operator prior to use, and are widely used in modern life science laboratories. Thumb-controlled micropipettes are also used in embryo manipulation, and are sold, for example, by CooperSurgical under the name The STRIPPER® (https: / / fertility.coopersurgical.com / micropipettes / the-stripper / #toggle).

[0007] Micropipettes have the advantage of avoiding the potential problems associated with mouthpiece-type devices (i.e., the need to exhale and use the mouth during operation). However, many practitioners feel that conventional micropipettes are far inferior to mouthpiece-type devices in terms of their ability to intuitively and precisely control the injection and ejection of fluids. This is thought to be one of the main reasons why the use of micropipettes remains unpopular among Japanese embryo manipulation practitioners, and mouthpiece-type devices continue to be used. In other words, in the field of assisted reproductive technology, the original purpose of a micropipette, as described in Patent Document 1, is not the ability to accurately aspirate and eject a pre-specified amount of liquid. Rather, what is required is the ability to intuitively and freely change the amount of liquid (including embryonic cells) being aspirated and ejected during the operation, down to the individual cell level, depending on the number and condition of the embryos being handled.

[0008] Electronic micropipettes also exist, which can aspirate and dispense precise volumes of liquid down to the microliter scale, but are not good at dynamically adjusting the volume of liquid according to the operator's sense. There are also fixed-type hydraulic or pneumatic micropipettes (microinjectors) used for specialized applications such as microinjection, but these devices are expensive and have limited range of operation and applications.

[0009] U.S. Patent No. 3,827,305

[0010] The embodiments of the present disclosure provide a micropipette system that allows an operator to control the intake and discharge of fluid with an intuitiveness comparable to that of a mouthpiece-type operation.

[0011] The present disclosure includes the following embodiments: [1] A micropipette system comprising: a body having a long axis and proximal and distal ends, and a tubular cavity extending along at least a portion of the long axis; a rotatable wheel having an axis of rotation in a proximal region of the body; a pump member configured to move back and forth in a distal or proximal direction within the body in response to rotational movement of the wheel; and a microcapillary needle extending proximally from the body, wherein an outer edge of the wheel is at least partially exposed from the body, and the microcapillary needle has an interior space communicating with the tubular cavity of the body, and the back and forth movement of the pump member increases or decreases the volume of the tubular cavity, thereby allowing fluid to be drawn into or expelled from the interior space of the microcapillary needle. [2] The micropipette system according to [1], wherein the tubular cavity extends distally of the pump member, and the tubular cavity and the internal space of the microcapillary needle are in communication with each other via a conduit that makes a U-turn from the distal direction to the proximal direction. [3] The pump member has a piston that fits into the inner diameter of the tubular cavity and is movable back and forth within the tubular cavity, and a linear gear that is connected to the piston and extends on the opposite side of the tubular cavity. The micropipette system according to [1] or [2], wherein the micropipette system further includes a circular gear that rotates integrally with the wheel, the rotation axis of the wheel being fixed to the body, and the back and forth movement of the pump member based on a rack-and-pinion mechanism caused by engagement between the circular gear and the linear gear links the rotational movement of the wheel with the back and forth movement of the pump member. [4] The micropipette system described in [3], wherein the engagement between the circular gear and the linear gear in the rack-and-pinion mechanism is indirect engagement via one or more additional circular gears engaged between the circular gear and the linear gear, and one of the one or more additional circular gears directly engages with the linear gear, rather than the circular gear.[5] The micropipette system according to [3] or [4], wherein the circular gear is concentric with the wheel and coupled to the wheel, and the diameter of the circular gear is 2 / 3 or less of the diameter of the wheel. [6] The micropipette system according to [1] or [2], wherein the tubular cavity is at least partially provided by a flexible tubing region, a second wheel is coupled to the wheel and rotates concentrically with the wheel, and one of the wheel and the second wheel forms a circular gear, the body includes a body-fixed linear gear that extends along the longitudinal axis and is fixed to the body and engages with the circular gear, the wheel and the second wheel move along the body-fixed linear gear as the circular gear rolls on the body-fixed linear gear when rotating, and the outer edge of the wheel or the second wheel that does not form the circular gear circumscribes the flexible tubing region and presses against the tubular cavity within the flexible tubing region, thereby forming a pump member based on a peristaltic pump mechanism that moves back and forth in conjunction with the rotational movement of the wheel. [7] The micropipette system according to [1] or [2], wherein the pump member has a piston that fits into the inner diameter of the tubular cavity and is movable back and forth within the tubular cavity, and a connecting rod that is connected to the piston and extends away from the tubular cavity, the connecting rod being fixed to the rotation axis of the wheel at an end opposite to the end connected to the piston, the micropipette system including a circular gear that rotates integrally with the wheel, the body including a fixed linear gear that extends along the longitudinal axis and is fixed to the body and engages with the circular gear, the wheel moving along the fixed linear gear as the circular gear rolls on the fixed linear gear, and the movement of the wheel along the fixed linear gear also moves the pump member via the connecting rod, thereby linking the rotational movement of the wheel with the back and forth movement of the pump member.[8] The micropipette system according to [1] or [2], wherein the pump member has a piston that fits into the inner diameter of the tubular cavity and is movable back and forth within the tubular cavity, a connecting rod is fixed to the piston, extending on the opposite side of the tubular cavity, the rotation axis of the wheel is fixed to the body, the connecting rod is fixed at an end opposite to the end fixed to the piston, at a position on the wheel that is offset from the rotation axis, and a slider crank mechanism formed by connecting the wheel and the piston with the connecting rod links the rotational movement of the wheel with the back and forth movement of the pump member. [9] The micropipette system according to [8], further comprising: a circular gear that rotates integrally with the wheel; and one or more additional circular gears that engage with the circular gear; the connecting rod is fixed at an end opposite to the end fixed to the piston, at a position that is not connected to the wheel but to the rotation axis of one of the one or more additional circular gears; and a slider-crank mechanism formed by connecting the additional circular gear and the piston by the connecting rod provides a link between the rotational movement of the wheel and the back-and-forth movement of the pump member.

[10] The micropipette system according to [1] or [2], wherein the pump member has a piston that fits into the inner diameter of the tubular cavity and can move back and forth within the tubular cavity, and a connecting rod that is connected to the piston and extends on the opposite side of the tubular cavity, the rotation axis of the wheel is fixed to the body, and the wheel has a pin positioned off the rotation axis, the connecting rod is connected to a yoke including a slot at the end opposite to the end connected to the piston, and a Scotch yoke mechanism formed by the pin on the wheel engaging in the slot provides linkage between the rotational movement of the wheel and the back and forth movement of the pump member.

[11] The micropipette system according to

[10] , further comprising: a circular gear that rotates integrally with the wheel and one or more additional circular gears that engage with the circular gear; the pin that engages with the slot in the yoke is located off the axis of rotation on one of the one or more additional circular gears rather than on the wheel; and a Scotch yoke mechanism formed by the pin on the additional circular gear engaging in the slot provides linkage between the rotational movement of the wheel and the back-and-forth movement of the pump member.

[12] The micropipette system according to any of [1] to

[11] , wherein the microcapillary needle is based on a Pasteur pipette, the tip of which forms a needle and the end of which is fixed to the body.

[13] The micropipette system according to any of [1] to

[12] , wherein the microcapillary needle is removable from the body and replaceable.

[14] A micropipettor comprising: a body having a long axis and proximal and distal ends, and a tubular cavity extending along at least a portion of the long axis; a rotatable wheel having an axis of rotation in a proximal region of the body; a pump member configured to move back and forth in a distal or proximal direction within the body in conjunction with the rotational movement of the wheel; and a microcapillary needle insertion port that opens proximally to receive a microcapillary needle extending proximally from the body, wherein an outer edge of the wheel is at least partially exposed from the body, and the microcapillary needle insertion port is in communication with the tubular cavity of the body, and the back and forth movement of the pump member increases or decreases the volume of the tubular cavity, thereby allowing the intake or expulsion of a fluid in an internal space of a microcapillary needle inserted into the microcapillary needle insertion port.

[15] A micropipette kit comprising the micropipette according to

[14] and a microcapillary needle.

[16] The micropipettor according to

[14] , which receives a microcapillary needle in the microcapillary needle insertion port to form the micropipette system according to any one of [1] to

[13] .

[0012] FIG. 1 shows the appearance of a micropipette system according to one embodiment, held in a "pencil grip" by an operator's hand. FIG. 2 schematically illustrates an embodiment in which the rotational movement of the wheel and the back-and-forth movement of the pump member are linked based on a rack-and-pinion mechanism. (a) and (b)-(d) embodiments are shown, respectively, without and with an additional circular gear. FIG. 3 schematically illustrates an embodiment in which the outer edge of the wheel itself constitutes the pump member based on a peristaltic pump mechanism. FIG. 4 schematically illustrates an embodiment in which movement of the wheel along a linear gear fixed to the body also moves the pump member via a connecting rod, thereby linking the rotational movement of the wheel and the back-and-forth movement of the pump member. FIG. 5 schematically illustrates an embodiment in which the rotational movement of the wheel and the back-and-forth movement of the pump member are linked based on a slider-crank mechanism. FIG. 6 schematically illustrates an embodiment in which the rotational movement of the wheel and the back-and-forth movement of the pump member are linked based on a Scotch yoke mechanism. FIG. 7 shows an example of how the distal end of a microcapillary needle is inserted into a microcapillary needle insertion port.

[0013] [Micropipette System] The micropipette system of the present disclosure will be described with reference to the drawings, which are non-limiting examples. In one aspect, the present disclosure provides a micropipette system 1. A micropipette generally refers to a pipette for aspirating and dispensing fluids on a microliter scale or smaller. For example, a pipette commonly used for embryo manipulation is a micropipette. As shown in FIG. 1 , the micropipette system of this embodiment has a body 10 having a long axis 10a and proximal and distal ends 10b and 10c. The long axis here refers to an axis defined conceptually rather than a physical structure. The body is typically elongated, and it is understood that the length along the long axis is greater than the thickness. In this disclosure, "proximal" means closer to the sample along the long axis when manipulating a sample such as an embryo using the micropipette system, and "distal" means farther from the sample. The proximal end of the pipette can also be referred to as the tip of the pipette, and the distal end of the pipette can also be referred to as the end of the pipette. In the accompanying drawings, the micropipette system 1 is shown with the proximal direction to the left (x) and the distal direction to the right (y).

[0014] As is not visible in Figure 1 but is shown in Figures 2-6, the body of the micropipette system of this embodiment has a tubular cavity 11 extending along at least a portion of its longitudinal axis 10a. By the tubular cavity extending along the longitudinal axis, we mean that the tubular cavity extends generally parallel to the longitudinal axis.

[0015] The micropipette system of this embodiment includes a rotatable wheel 20, the axis of rotation 21 of which is located in the proximal region of the body 10, i.e., proximal to the center. In a preferred embodiment, the axis of rotation 21 of the wheel 20 is located within a region of the body 10 that is within one-third or one-quarter of the total length from the proximal end. The axis of rotation 21 of the wheel is preferably generally perpendicular to the longitudinal axis 10a of the body. The diameter of the wheel is typically within the range of 1 to 5 cm, and more typically within the range of 1.5 to 4 cm.

[0016] The outer edge 22 of the wheel 20 is at least partially exposed from the body 10. Therefore, an operator of the micropipette system 1 can hold the body 10 in one hand, touch the outer edge 22 of the wheel 20 with one finger of that hand, and rotate the wheel 20 back and forth with the force of the finger.

[0017] The micropipette system 1 of this embodiment is a handheld micropipette system. The micropipette system 1 of this embodiment has the advantage of being held in a "pencil grip" style, allowing intuitive control with the index finger (or thumb or middle finger). This advantage is due to the fact that the rotation axis of the wheel is located in the proximal region. "Pencil grip" is a common expression in Japanese and refers to the usual hand position for holding a writing instrument such as a pencil or pen. In other words, as shown in FIG. 1 , when the micropipette system of this embodiment is held in a pencil grip, the body 10 is held at at least three points: the pads of the index finger and thumb (where fingerprints are located) and the inside of the middle finger (the side that normally contacts the index finger) (or four points, including the area near the base of the index finger). By touching the wheel 20 with the index finger and rotating it at will without substantially changing the hand position, the user can delicately control the intake and discharge of fluid into the microcapillary needle 40. The inventors have discovered that the combination of this "pencil grip" with a wheel that can be rotated with a single index finger significantly improves the intuitiveness, reliability, and efficiency of embryo manipulation. The intuitiveness of operation with this micropipette system is comparable to that of a mouthpiece-type system. Furthermore, the micropipette system of this embodiment is not subject to the potential safety issues associated with mouthpiece-type systems.

[0018] Preferably, the wheel 20 is not spring-loaded. Spring-loaded means that a spring is involved, so that a displaced component returns to its original position due to the spring's elasticity. Conventional thumb-controlled micropipettes have a spring-loaded distally protruding rod. This is because, with the thumb of an operator holding a thumb-controlled micropipette, it is easy to push the rod but difficult to pull it. This reliance on springs, i.e., reliance on elasticity, contributes to a relative decrease in the intuitiveness and delicacy of operation. While possible, spring-loaded wheels and other components are not required in the micropipette system of this embodiment.

[0019] The length of the body 10 is typically within the range of 5 to 20 cm, and preferably within the range of 6 to 18 cm, or 7 to 16 cm. The diameter of the part of the body 10 that comes into contact with the hand during normal use of the micropipette system is typically within the range of 1.5 to 5 cm.

[0020] The micropipette system 1 of this embodiment includes a pump member 30 configured to move back and forth in a distal or proximal direction within the body 10 in conjunction with the rotational movement of the wheel 20. In this disclosure, "rotational movement" or "rotation" refers to movement by a certain angle while being constrained by the axis of rotation, and does not necessarily require a 360° rotation. In fact, the rotation angle corresponding to the adjustment of microliter-scale fluid volumes may typically be less than 180°. Numerous mechanisms are known that can convert the rotational movement of one member into the linear movement of another member, and these mechanisms may be utilized in this embodiment. It is generally understood that when an object rotates back and forth (i.e., in one rotational direction and the opposite rotational direction), the part away from the axis of rotation moves back and forth in an arc. The mechanism for converting rotational movement into linear movement can utilize this basic property in various ways. Non-limiting examples are described herein.

[0021] The micropipette system 1 of this embodiment further includes a microcapillary needle 40 extending proximally from the body 10. As will be understood by those skilled in the art of embryo manipulation, a microcapillary needle refers to a hollow tube whose tip typically narrows to an inner diameter of 600 μm or less (e.g., 50-600 μm, or 75-300 μm) to form a needle. The microcapillary needle is typically transparent. The material of the microcapillary needle is preferably, but not limited to, glass, and may be a plastic such as polycarbonate. As known to those skilled in the art, a microcapillary needle can be fabricated, for example, by heating a Pasteur pipette or capillary tube to thin it, followed by appropriate processing (e.g., trimming) to adjust the diameter and / or shape of the tip. In some embodiments, the microcapillary needle 40 is based on a Pasteur pipette, where the tip of the Pasteur pipette forms the needle and the end is attached to the body 10. As will be understood by those skilled in the art, a Pasteur pipette is a pipette, typically made of glass, that is typically fitted with a rubber bulb at its end. The end of a microcapillary needle typically has a significantly larger outer and inner diameter than the tip. For example, in the case of a microcapillary needle based on a Pasteur pipette, the original end of the Pasteur pipette, where the rubber bulb would normally be attached, may serve as the end of the microcapillary needle 40.

[0022] The microcapillary needle 40 has an internal space 41 that communicates with the tubular cavity 11 of the body. The back and forth movement of the pump member 30 increases or decreases the volume of the tubular cavity 11, thereby allowing the intake or discharge of fluid into or from the internal space of the microcapillary needle 40. It has been found that by holding the body 10 like a pencil and rotating the wheel 20, which has a rotation axis in the proximal region of the body, with a finger, the operator's intuitive intention, the change in the volume of the tubular cavity, and the intake or discharge of a microliter-scale amount of fluid into or from the microcapillary needle can be precisely coordinated.

[0023] In a particularly preferred embodiment, the tubular cavity 11 of the body extends distally relative to the pump member 30, and the tubular cavity 11 and the internal space 41 of the microcapillary needle are connected by a conduit 50 that makes a U-turn from the distal direction to the proximal direction. This embodiment is preferable compared to an embodiment in which the tubular cavity extends proximally relative to the pump member and directly connects to the microcapillary needle, because the presence of the additional volume provides a moderate cushion, significantly improving the operator's ability to finely adjust the amount of fluid as intended, and it does not impair the ease of holding and compactness of the entire micropipette system. The "U-turn" refers to a conduit that extends distally, then turns proximally midway to connect to the microcapillary needle; however, its shape does not have to be literally U-shaped. For example, the U-turn conduit may be a tube (e.g., a flexible tube such as a rubber tube) connected to the body 10 and exposed outside the body. Alternatively, the U-turn conduit may be a cavity or tube incorporated inside the body 10 as illustrated in the drawings.

[0024] The microcapillary needle 40 of the micropipette system 1 of the present disclosure is preferably detachable and replaceable from the body 10. In the present disclosure, a product from which the microcapillary needle 40 has been detached is specifically referred to as a "micropipettor." By attaching a microcapillary needle to the micropipettor, a micropipette that can be used for embryo manipulation and the like is formed.

[0025] A non-limiting example of a mechanism for moving the pump member 30 back and forth distally or proximally within the body 10 in conjunction with the rotational movement of the wheel 20 will now be described.

[0026] In the embodiment shown in FIG. 2 , the pump member 30 includes a piston 31 that fits within the inner diameter of the tubular cavity 11 and can move back and forth within the tubular cavity 11, and a linear gear 32 that is connected to the piston 31 and extends on the opposite side of the tubular cavity (i.e., the tubular cavity that communicates with the internal space 41 of the microcapillary needle). This micropipette system includes a circular gear 23 that rotates integrally with the wheel 20. In one example, as shown in FIGS. 2 a and 2 b, a circular gear 23 concentric with the wheel 20 may be connected to the wheel 20. In another example, as shown in FIGS. 2 c and 2 d, the wheel 20 itself may be the circular gear 23. In this case, the operator operates the wheel by touching the teeth of the circular gear 23 / 20 with their fingers. The rotation axis 21 of the wheel is fixed to the body. The term "fixed" as the rotation axis means that the position of the rotation axis is fixed, and the rotation of the wheel or the like occurs at that position. In these embodiments, the back and forth movement of the pump member is based on a rack and pinion mechanism, which is achieved by the engagement of the circular gear 23 with the linear gear 32, providing a link between the rotational movement of the wheel and the back and forth movement of the pump member. The piston 31 may include a gasket portion and a plunger portion that fit into the inner diameter of the tubular cavity, like the piston of a syringe (as exemplified in Figures 2c and 2d, but equally applicable to other embodiments).

[0027] The engagement between the circular gear 23 and the linear gear 32 in the rack-and-pinion mechanism may be indirect via one or more additional circular gears 60 engaged between the circular gear 23 and the linear gear 32, as shown in Figures 2b to 2d. In this case, one of the one or more additional circular gears 60, rather than the circular gear 23 itself, directly engages with the linear gear 32. In this disclosure, when there are multiple additional circular gears, the term "engages" an additional circular gear with a circular gear means that the circular gear directly engages with the first additional circular gear, the first additional circular gear directly engages with the second additional circular gear, and so on. The final additional circular gear directly engages with the linear gear 32. As illustrated in Figure 2d, the additional circular gear 60 may include two or more gears concentrically coupled, so that the gear engaging with the preceding circular gear and the gear engaging with the subsequent circular gear (or linear gear) within one additional circular gear 60 may be different. The terms "leading" and "following" used here indicate that the rotation of the wheel 20 by a finger is the starting point, i.e., the first, and the movement of the gear is then propagated.

[0028] In an embodiment in which the upper outer edge 22 of the wheel 20 is exposed from the body 10 and engagement with the linear gear 32 occurs below the additional circular gear 60, when the number of additional circular gears 60 is one or an odd number, the rotational movement of the wheel 20 and the back-and-forth movement of the pump member 30 are coupled in the opposite direction compared to when there is no additional circular gear 60. When the number of additional circular gears 60 is two or an even number, the rotational movement of the wheel 20 and the back-and-forth movement of the pump member 30 are coupled in the same direction compared to when there is no additional circular gear 60. In a particularly preferred embodiment, as shown in FIGS. 2b to 2d, the tubular cavity 11 and the internal space 41 of the microcapillary needle are communicated by a U-turning conduit 50, and the number of additional circular gears 60 is one or an odd number. It will be understood that the rotational axis of each of the one or more additional circular gears 60 is typically fixed to the body.

[0029] The one or more additional circular gears 60 can change the direction of the link between the rotational movement of the wheel 20 and the back-and-forth movement of the pump member 30. This allows the relationship between the rotational direction of the wheel 20 and the direction of liquid flow in and out of the microcapillary needle to be optimized to better suit the intuition of each individual user. In this way, the additional circular gears 60 can reverse the movement direction of the pump member 30 relative to the rotational direction of the wheel 20 or serve to bridge the distance between the circular gear 23 and the linear gear 32, but can also be provided as "idler gears" that do not necessarily affect the movement distance of the piston 31 in response to the rotation of the wheel 20.

[0030] As illustrated in FIG. 2 a , an embodiment in which the diameter of the circular gear 23 concentric with the wheel 20 and engaged with the linear gear 32 is smaller than the diameter of the wheel 20 (for example, 2 / 3 or less, 1 / 2 or less, or 1 / 3 or less (typically 1 / 10 or more)) is particularly preferred for fine operability through finger movement. Specifically, the smaller the diameter of the circular gear 23 is compared to the diameter of the wheel 20, the fewer the number of gear teeth the circular gear 23 has. Furthermore, the movement distance of the linear gear 32 caused by rotating the wheel 20 is expressed as "the circumferential movement distance of the outer edge of the wheel 20" x "the diameter of the circular gear 23 / the diameter of the wheel 20." Therefore, the greater the difference between the diameters, the shorter the movement distance of the linear gear 32 per the same rotation angle of the wheel 20, and the slower the linear motion of the linear gear 32. In other words, the greater the difference between the diameters, the weaker the force required to operate the piston 31 and the easier it is to adjust fine movements. Accordingly, the movement of the air or liquid near the tip of the microcapillary needle 40 is also slowed down, ultimately improving the fine manipulation ability to handle liquid containing an embryo or the like.

[0031] In a preferred example of the embodiment shown in FIG. 2a, the wheel 20 has two layers of wheel discs of the same diameter that sandwich the circular gear 23, with the linear gear 32 extending between the two layers, and engagement between the linear gear 32 and the circular gear 23 occurring between the two layers of wheel discs. The reason this embodiment is preferred is that sandwiching the linear gear 32 between two layers of wheel discs prevents the linear gear 32 from tipping over or deviating from its orbit, stabilizing the linear gear 32's movement back and forth along its linear orbit. However, this is merely one example of a configuration for stabilizing the linear motion of the linear gear 32, and is not limited to this. For example, instead of sandwiching the linear gear 32 between two layers of wheel discs, it is also possible to prevent the linear gear 32 from tipping over or deviating from its orbit during operation by providing a support structure that supports the linear gear 32 from the side opposite the circular gear 23 or from the bottom. The smaller the area of ​​the bottom portion of the linear gear 32 that comes into contact with the body 10 when the linear gear 32 moves linearly, the weaker the frictional resistance, making it possible to operate the linear gear 32 with less force.

[0032] In the example of FIG. 2b, an embodiment in which the diameter of the circular gear 23 engaging with the additional circular gear 60 is smaller than the diameter of the wheel 20 (for example, 2 / 3 or less, 1 / 2 or less, or 1 / 3 or less (typically 1 / 10 or more)) is particularly preferred for fine operability through finger movements. As explained with reference to FIG. 2a, the smaller the diameter of the circular gear 23 is compared to the diameter of the wheel 20, the fewer the number of gear teeth the circular gear 23 has. This reduces the number of gear teeth or arc length involved in engagement per the same rotation angle of the wheel 20, thereby shortening the moving distance of the linear gear 32 and slowing down the linear motion of the linear gear 32. In other words, the greater the difference between the diameters of the two, the weaker the force required to operate the piston 31 and the easier it is to adjust fine movements. As mentioned above, this leads to improved fine operability when handling liquids containing embryos, etc.

[0033] In a preferred example of the embodiment shown in Figure 2b, the wheel 20 has two layers of wheel discs of the same diameter sandwiching the circular gear 23, and the additional circular gear 60 is inserted between the two layers of wheel discs and engages with the circular gear 23. Furthermore, it is also possible to arrange the linear gear 32 so that it extends between the two layers of wheel discs. However, the configuration in which the wheel discs are made into two layers and the additional circular gear and / or linear gear are sandwiched between them is merely one example for stabilizing and strengthening the mechanism, and other configurations such as those described above are also possible.

[0034] In a preferred example of the embodiment shown in Figure 2c, the circular gear 23 includes two layers of gears of the same diameter (so that the cross section including the shaft 21 is H-shaped), the linear gear 32 extends between the two layers, and the additional circular gear 60 is cylindrical and engages with the two layers of gears and the linear gear. This is just one non-limiting example to stabilize and robusten the mechanism.

[0035] As illustrated in FIG. 2d , a preferred embodiment is one in which the additional circular gear 60 includes two concentrically coupled gears, and the diameter of the gear engaging with the linear gear 32 is smaller than the diameter of the gear engaging with the circular gear 23 (for example, 2 / 3 or less, 1 / 2 or less, or 1 / 3 or less (typically 1 / 10 or more)). The relationship between these two coupled gears is similar to the relationship between the wheel 20 and the circular gear 23 described with reference to FIGS. 2a and 2b . In other words, when the diameter of the gear engaging with the subsequent gear of the two gears included in one additional circular gear 60 is reduced compared to the diameter of the gear engaging with the preceding gear, a conversion occurs in which the number of gear teeth or arc length involved in engagement within the additional circular gear 60 is proportionally reduced. Therefore, the moving distance of the linear gear 32 is also shortened, and the linear motion of the linear gear 32 is decelerated. This allows the piston 31 to be operated with a weaker force and makes it easier to adjust fine movements.

[0036] In the embodiment shown schematically in Figure 3, the tubular cavity 11 is provided at least in part by the flexible tube region 11a. A second wheel 24 is coupled to the wheel 20 and rotates concentrically with the wheel 20, and one of the wheel 20 and the second wheel 24 (second wheel 24 in Figure 3) forms a circular gear 25. The barrel 10 includes a fixed barrel linear gear 12 that extends along the longitudinal axis 10a and is fixed to the barrel 10 and engages with the circular gear 25. As the wheel 20 and the second wheel 24 rotate, the circular gear 25 rolls on the barrel-fixed linear gear 12, moving along the barrel-fixed linear gear. The outer edge 26 of the wheel 20 or the second wheel 24 that does not constitute the circular gear 25 (wheel 20 in FIG. 3 ) circumscribes the flexible tube region 11a and compresses the tubular cavity within the flexible tube region, thereby forming a pump member 30 based on a peristaltic pump mechanism that moves back and forth in conjunction with the rotational movement of the wheel 20. The barrel 10 of the present disclosure may be generally cylindrical, box-like, or case-like. Typically, the barrel-fixed linear gear 12 is fixed inside the barrel 10, and the interior of the barrel 10 may further include an axis guide 13 that defines the range of movement of the wheel rotation axis 21. The axis guide 13 may be a window that opens to the outside of the barrel 10. In the embodiment shown in Fig. 3, the barrel-fixed linear gear 12 extends parallel to the longitudinal axis of the barrel 10, but the barrel-fixed linear gear 12 may be inclined with respect to the longitudinal axis of the barrel. For example, in Fig. 3, if the barrel-fixed linear gear 12 is inclined toward the distal direction, the pump member 30 will compress the flexible tube region 11a more strongly as the wheel 20 is rotated and moved distally.

[0037] In the embodiment shown in Fig. 4, the pump member 30 has a piston 33 that fits into the inner diameter of the tubular cavity 11 and can move back and forth within the tubular cavity 11, and a connecting rod 34 that is connected to the piston 33 and extends away from the tubular cavity 11, the connecting rod 34 being fixed to the rotation axis 21 of the wheel 20 at the end opposite to the end connected to the piston 33. The micropipette system in these embodiments includes a circular gear 27 that rotates integrally with the wheel 20. As in the case of the rack-and-pinion mechanism described above, the wheel 20 itself may be the circular gear 27, or, as shown in Fig. 4, a circular gear 27 concentric with the wheel 20 may be connected to the wheel. The body 10 includes a body fixed linear gear 14 that extends along the longitudinal axis 10a and is fixed to the body 10 and engages with the circular gear 27. When the wheel 20 rotates, the circular gear 27 rolls on the body fixed linear gear 14, causing the wheel 20 to move along the body fixed linear gear 14. The movement of the wheel 20 along the body fixed linear gear 14 also moves the pump member 30 (particularly the piston 33) via the connecting rod 34, thereby providing a link between the rotational movement of the wheel and the back and forth movement of the pump member.

[0038] 3 and 4, in embodiments involving a fixed barrel linear gear, rotation of the wheel 20 causes the wheel 20 itself to move distally or proximally, but because the movement distance corresponding to microliter-scale fluid volumes is small, the operator can still operate the micropipette system 1 via the wheel 20 while essentially maintaining a pencil grip.

[0039] 5, the pump member 30 has a piston 35 that fits into the inner diameter of the tubular cavity 11 and is movable back and forth within the tubular cavity 11. A connecting rod 36 is fixed to the piston 35, extending on the opposite side of the tubular cavity 11. The rotation axis 21 of the wheel 20 is fixed to the body, and the connecting rod 36 is fixed at an end opposite to the end fixed to the piston 35, at a position on the wheel 20 that is offset from the rotation axis. In these embodiments, a slider-crank mechanism formed by connecting the wheel 20 and the piston 35 with the connecting rod 36 provides linkage between the rotational movement of the wheel and the back and forth movement of the pump member. It is understood that the fixing of the rod 36 to the wheel 20 and the piston 35 is fixing that allows rotation or swinging, respectively. Alternatively, a variation of the micropipette system utilizing the slider-crank mechanism described above may have a circular gear that rotates integrally with the wheel 20 and one or more additional circular gears that engage with the circular gear, and the connecting rod 36 is fixed at the end opposite the end fixed to the piston 35 to a position offset from the rotation axis of one of the one or more additional circular gears (rather than the wheel 20). The rotation axis of the additional circular gear may be fixed to the barrel. The significance and variations of the additional circular gears are similar to those described with respect to the embodiment of FIG. 2.

[0040] 6, the pump member 30 includes a piston 37 that fits within the inner diameter of the tubular cavity 11 and can move back and forth within the tubular cavity 11, and a connecting rod 38 that is connected to the piston 37 and extends away from the tubular cavity 11. The rotation axis 21 of the wheel 20 is fixed to the body, the wheel 20 has a pin 70 positioned away from the rotation axis 21, and the connecting rod 38 is connected to a yoke 71 that includes a slot at the end opposite the end connected to the piston 37. In these embodiments, a Scotch yoke mechanism formed by the pin 70 on the wheel 20 engaging with the slot provides linkage between the rotational movement of the wheel and the back and forth movement of the pump member. Alternatively, a variation of the micropipette system using the Scotch yoke mechanism includes a circular gear that rotates integrally with the wheel 20 and one or more additional circular gears that engage with the circular gear, and the pin 70 that engages with the slot in the yoke 71 is located away from the rotation axis on one of the one or more additional circular gears (rather than the wheel 20). The rotation axis of the additional circular gear may be fixed to the barrel, and the significance and variations of the additional circular gear are the same as those described with respect to the embodiment of FIG.

[0041] Micropipettor. In another aspect, the present disclosure provides a micropipettor. This micropipettor can be understood to essentially correspond to any of the micropipette systems described above, prior to the attachment of a microcapillary needle 40. The micropipettor has an insertion port 80 for receiving a microcapillary needle 40. Thus, in a basic embodiment, the micropipettor includes a body having a longitudinal axis and proximal and distal ends, and a tubular cavity extending along at least a portion of the longitudinal axis; a rotatable wheel having an axis of rotation in a proximal region of the body; a pump member configured to move back and forth distally or proximally within the body in conjunction with the rotational movement of the wheel; and a microcapillary needle insertion port that opens proximally for receiving a microcapillary needle extending proximally from the body. The outer edge of the wheel is at least partially exposed from the body. It should be understood that the structural and functional descriptions provided for various embodiments of the micropipette system can each be applied to the corresponding micropipettor. The microcapillary needle insertion port 80 communicates with the tubular cavity of the body, and the back and forth movement of the pump member increases or decreases the volume of the tubular cavity, thereby allowing the intake or exhaust of fluid in the internal space 41 of the microcapillary needle when the microcapillary needle 40 is inserted into the microcapillary needle insertion port 80.

[0042] The shape of the microcapillary needle insertion port 80 is not particularly limited as long as it can achieve airtightness between the inserted microcapillary needle and the micropipettor, and can be appropriately determined by those skilled in the art based on the shape and size of the end of the microcapillary needle to be used. For example, in the example shown in the schematic cross-sectional view of FIG. 7a, the microcapillary needle insertion port 80 has a tapered internal shape so that the end of the microcapillary needle 40 (such as that based on a Pasteur pipette) can be pushed in to establish airtight communication. Alternatively, the microcapillary needle insertion port 80 may have an O-ring 81 made of rubber or the like so that the end of the microcapillary needle 40 can be pushed in to establish airtight communication, as in the example shown in the schematic cross-sectional view of FIG. 7b. In a preferred embodiment, the microcapillary needle 40 is based on a Pasteur pipette, and the microcapillary needle insertion port 80 is located distal to the rotation axis 21 of the wheel 20. This arrangement is preferable because it provides an overall shape of the micropipette system that is optimal for operation using the wheel 20 while holding the microcapillary needle like a pencil.

[0043] [Micropipette Kit] In another aspect, the present disclosure provides a micropipette kit including any of the micropipetters described above and a microcapillary needle. A user can prepare a usable micropipette system by inserting the end of the microcapillary needle provided in the kit into the microcapillary needle insertion port of the micropipette.

[0044] Various embodiments of the micropipette systems, micropipettors, and micropipette kits of the present disclosure find particular utility in fields such as assisted human reproduction, livestock breeding technology, and laboratory animal reproductive engineering, but may also be useful in a variety of other technical fields requiring delicate manipulation of microliter-scale or submicroliter volumes of fluids or particulate suspensions.

[0045] 1 Micropipette system 10 Body 20 Wheel 30 Pump member 40 Microcapillary needle 50 U-turn conduit 60 Additional circular gear 80 Microcapillary needle insertion port

Claims

1. A micropipette system comprising: a body having a long axis and proximal and distal ends, the body having a tubular cavity extending along at least a portion of the long axis; a rotatable wheel having an axis of rotation in a proximal region within one-third of the length of the body from the proximal end; a pump member configured to move back and forth in a distal or proximal direction within the body in response to rotational movement of the wheel; and a microcapillary needle extending proximally from the body, wherein an outer edge of the wheel is at least partially exposed from the body, the microcapillary needle has an interior space communicating with the tubular cavity of the body, and the back and forth movement of the pump member increases or decreases the volume of the tubular cavity, thereby allowing the intake or expulsion of fluid in the interior space of the microcapillary needle.

2. A micropipette system as described in claim 1, wherein the tubular cavity extends distally of the pump member, and the tubular cavity and the internal space of the microcapillary needle are connected by a conduit that makes a U-turn from the distal direction to the proximal direction.

3. The micropipette system according to claim 1, wherein the pump member has a piston that fits into the inner diameter of the tubular cavity and is movable back and forth within the tubular cavity, and a linear gear that is connected to the piston and extends on the opposite side of the tubular cavity, the micropipette system includes a circular gear that rotates integrally with the wheel, the rotation axis of the wheel being fixed to the body, and the back and forth movement of the pump member based on a rack and pinion mechanism caused by the engagement between the circular gear and the linear gear provides a link between the rotational movement of the wheel and the back and forth movement of the pump member.

4. The micropipette system of claim 3, wherein the engagement between the circular gear and the linear gear in the rack and pinion mechanism is indirect engagement via one or more additional circular gears engaged between the circular gear and the linear gear, and one of the one or more additional circular gears, rather than the circular gear, directly engages with the linear gear.

5. A micropipette system as described in claim 3 or 4, wherein the circular gear is concentric with and connected to the wheel, and the diameter of the circular gear is less than or equal to 2 / 3 of the diameter of the wheel.

6. The micropipette system of claim 1, wherein the tubular cavity is provided at least in part by a flexible tube region, wherein a second wheel is coupled to the wheel and rotates concentrically therewith, one of the wheel and the second wheel forming a circular gear, wherein the body includes a body-fixed linear gear extending along the long axis and fixed to the body and engaging with the circular gear, wherein the wheel and the second wheel move along the body-fixed linear gear as they rotate, with the circular gear rolling on the body-fixed linear gear, and wherein the outer edge of the wheel or the second wheel not constituting the circular gear circumscribes the flexible tube region and presses against the tubular cavity within the flexible tube region, thereby the outer edge of the wheel itself constitutes a pump member based on a peristaltic pump mechanism which moves back and forth in conjunction with the rotational movement of the wheel.

7. The micropipette system of claim 1, wherein the pump member has a piston that fits into the inner diameter of the tubular cavity and is movable back and forth within the tubular cavity, and a connecting rod that is connected to the piston and extends opposite the tubular cavity, the connecting rod being fixed to the rotation axis of the wheel at an end opposite the end connected to the piston, the micropipette system includes a circular gear that rotates integrally with the wheel, the body includes a body-fixed linear gear that extends along the long axis and is fixed to the body and engages with the circular gear, and when the wheel rotates, the circular gear moves along the body-fixed linear gear by rolling on the body-fixed linear gear, and the movement of the wheel along the body-fixed linear gear also moves the pump member via the connecting rod, thereby providing a link between the rotational movement of the wheel and the back and forth movement of the pump member.

8. The micropipette system of claim 1, wherein the pump member has a piston that fits into the inner diameter of the tubular cavity and is movable back and forth within the tubular cavity, a connecting rod is fixed to the piston and extends on the opposite side to the tubular cavity, the axis of rotation of the wheel is fixed to the body, the connecting rod is fixed at an end opposite to the end fixed to the piston, at a position on the wheel that is offset from the axis of rotation, and a slider crank mechanism formed by connecting the wheel and the piston by the connecting rod provides a link between the rotational movement of the wheel and the back and forth movement of the pump member.

9. A micropipette system according to claim 8, further comprising a circular gear which rotates integrally with the wheel and one or more additional circular gears which engage with the circular gear, the connecting rod is fixed at an end opposite to the end fixed to the piston at a position which is offset from the rotation axis of one of the one or more additional circular gears rather than the wheel, and a slider-crank mechanism formed by connecting the additional circular gear and the piston via the connecting rod provides a link between the rotational movement of the wheel and the back and forth movement of the pump member.

10. The micropipette system of claim 1, wherein the pump member comprises a piston that fits into the inner diameter of the tubular cavity and is movable back and forth within the tubular cavity, and a connecting rod that is connected to the piston and extends on the opposite side of the tubular cavity, the axis of rotation of the wheel is fixed to the body and the wheel has a pin positioned away from the axis of rotation, the connecting rod is connected to a yoke including a slot at an end opposite to the end connected to the piston, and a Scotch yoke mechanism formed by the pin on the wheel engaging with the slot provides a link between the rotational movement of the wheel and the back and forth movement of the pump member.

11. A micropipette system as claimed in claim 10, further comprising a circular gear which rotates integrally with the wheel and one or more additional circular gears which engage with the circular gear, the pin which engages with the slot of the yoke is located off the axis of rotation on one of the one or more additional circular gears but not on the wheel, and a Scotch yoke mechanism formed by the pin on the additional circular gear engaging in the slot provides a link between the rotational movement of the wheel and the back and forth movement of the pump member.

12. The micropipette system of claim 1, wherein the microcapillary needle is based on a Pasteur pipette, the tip of the Pasteur pipette forming a needle and the end being fixed to the body.

13. The micropipette system of claim 1, wherein the microcapillary needle is removable and replaceable from the body.

14. A micropipettor comprising: a body having a long axis and proximal and distal ends, the body having a tubular cavity extending along at least a portion of the long axis; a rotatable wheel having an axis of rotation in a proximal region within one-third of the length of the body from the proximal end; a pump member configured to move back and forth in a distal or proximal direction within the body in conjunction with the rotational movement of the wheel; and a microcapillary needle insertion port opening in a proximal direction to receive a microcapillary needle extending proximally from the body, wherein an outer edge of the wheel is at least partially exposed from the body, the microcapillary needle insertion port communicates with the tubular cavity of the body, and the back and forth movement of the pump member increases or decreases the volume of the tubular cavity, thereby allowing the intake or expulsion of fluid in an internal space of a microcapillary needle inserted into the microcapillary needle insertion port.

15. A micropipette kit comprising the micropipettor according to claim 14 and a microcapillary needle.

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