Water-light microneedle wafer

Abstract

The application discloses a water-light microneedle wafer, which comprises a substrate and a microneedle array arranged on the substrate, at least one micropore penetrating through the substrate is arranged on the substrate, and the micropore is used for flowing of nutrient solution. Among a plurality of microneedles arranged circumferentially around the center of the micropore, at least one microneedle has at least two inclined surfaces on the side of the microneedle facing the micropore, the two inclined surfaces intersect on the side of the microneedle facing the micropore, and an inclined ridge line pointing to the center direction of the micropore is formed. The curvature radius of the inclined ridge line is much smaller than that of a smooth taper surface, a directional capillary driving force is generated, isotropy of the smooth taper surface is broken, the nutrient solution can be directed to the penetration channel entrance formed by the microneedle piercing the skin from the micropore, disorder diffusion of the nutrient solution is reduced, utilization is improved, and the wafer is not dependent on the placement direction. The application has high structural integration, is compatible with an existing microneedle etching process, and is suitable for medical cosmetology, skin drug delivery and other fields.

Description

Technical Field

[0001] This invention relates to the field of transdermal microneedle drug delivery technology, specifically to a water-light microneedle wafer, and more particularly to a water-light microneedle wafer with a microporous circumferential microneedle structure having directional drainage function. Background Technology

[0002] Microneedle transdermal drug delivery technology is a rapidly developing novel drug delivery method in recent years. It utilizes micron-scale needle-like structures to pierce the stratum corneum of the skin, forming microchannels on the skin surface to deliver drugs or nutrient solutions into the skin, achieving highly efficient transdermal delivery. Hyaluronic acid microneedle chips are an important type of product in this field. They typically consist of a substrate and an array of microneedles etched onto the substrate. The substrate has micropores that penetrate it, through which nutrient solutions flow. When the microneedles pierce the skin, the nutrient solution flows into the skin through the micropores and penetrates into the pores.

[0003] Existing technologies have disclosed basic structures for water-light microneedle wafers, including a substrate, a microneedle array, and through-hole micropores. For example, Chinese invention patent CN108310617A discloses an injectable microneedle wafer kit, in which a microneedle array and micropores for nutrient solution flow are provided on the substrate.

[0004] However, existing water-based microneedle chips generally suffer from the following technical problems: Existing microneedles typically have a smooth conical surface or a conventional smooth conical surface. At the micrometer scale, although capillary effect is dominant (capillary force is much greater than gravity), the smooth conical surface has axial symmetry, resulting in isotropic wetting and spreading of liquids on it—the capillary driving force of the liquid is equal in all directions along the conical surface, and the liquid has no preferred direction. Therefore, after the nutrient solution flows out of the micropores, it spreads isotropically and uniformly on the microneedle surface, unable to be directed to specific skin penetration channels (i.e., the channel entrance formed by the microneedle tip piercing the skin). This leads to a large-scale disordered diffusion of the nutrient solution on the substrate surface, with a large amount remaining on the skin surface and unable to effectively penetrate the subcutaneous layer, resulting in low utilization and a serious waste of active ingredients.

[0005] Therefore, how to provide a directional capillary pathway for the nutrient solution while retaining the microneedle puncture function, so that it can be precisely guided to the skin penetration channel, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] This invention provides a water-light microneedle wafer, which aims to solve the technical problems of existing water-light microneedle wafers, such as lack of directional guidance after the nutrient solution flows out of the micropores, easy disorderly diffusion in all directions, and low utilization rate of the nutrient solution.

[0007] To achieve the above objectives, the present invention provides a water-light microneedle wafer, the water-light microneedle wafer comprising a substrate and an array of microneedles disposed on the substrate, the substrate having at least one micropore penetrating the substrate, the micropore being used for the flow of nutrient solution, and among the plurality of microneedles arranged circumferentially around the center of the micropore, at least one of the microneedles having at least two inclined surfaces on the side facing the micropore, the at least two inclined surfaces intersecting on the side of the microneedle facing the micropore to form an inclined ridge line extending from the tip of the microneedle toward the edge or interior of the micropore and pointing toward the center of the micropore.

[0008] In this invention, the "center of the micropore" refers to the geometric center point of the micropore within the substrate plane (the center of the circle when the micropore is circular, and the intersection of the diagonals or the centroid when the micropore is polygonal). The "direction pointing towards the center of the micropore" of the inclined edge means that the projection of the inclined edge's extension direction onto the substrate plane points towards the geometric center point of the micropore; that is, the inclined edge extends from the tip of the microneedle towards the geometric center of the micropore. In this invention, the "inclined edge" refers to a linear edge structure formed by the intersection of two inclined surfaces, extending from the tip of the microneedle towards the center of the micropore, with an overall inclined orientation.

[0009] At the micrometer scale, capillary action is dominant, and gravity is negligible (Bond number Bo << 1). The capillary driving force of a liquid on a solid surface is closely related to the surface's radius of curvature—the smaller the radius of curvature, the greater the capillary driving force. In this invention, the ridge formed by the intersection of two inclined surfaces of the microneedle facing the micropore has a radius of curvature much smaller than that of a smooth conical surface (the ridge is a sharp edge, and its radius of curvature approaches zero). Therefore, the capillary driving force generated at the ridge is much greater than that of a smooth conical surface. More importantly, the ridge has a clear directionality (pointing towards the center of the micropore), which breaks the isotropy of the smooth conical surface and creates a directional flow path for the nutrient solution with a lower energy state. Since the capillary force is much greater than gravity, the directional flow function of this invention does not depend on the placement orientation of the wafer. Regardless of whether the chip is positioned with the microneedles facing down (the standard usage posture), up, or tilted to the side, the nutrient solution, driven by powerful directional capillary forces, is forcibly guided from the micropores to the microneedle tip and the skin penetration channel entrance along the tilted ridge, achieving directional drainage independent of gravity. This is fundamentally different from the existing mechanism of smooth conical surfaces that relies on gravity or isotropic spreading.

[0010] It should be noted that while multi-faceted pyramidal microneedles (such as triangular pyramids, square pyramids, or star-shaped pyramids) exist in the prior art, their ridges all extend along the microneedle axis, serving to enhance the microneedle's ability to pierce the skin or improve structural strength. These ridges are neither located on the side of the microneedle facing the micropore nor pointing towards the center of the micropore; therefore, they lack the function of guiding nutrient solution from the micropore to the microneedle tip. The inclined ridges of this invention originate from the needle tip and extend towards the micropore, functionally achieving a transformation from "mechanical piercing" to "liquid guidance," which is fundamentally different from the prior art.

[0011] This invention offers the following advantages: First, directional capillary drainage: The two inclined surfaces of the microneedle facing the micropore intersect to form a ridge. The radius of curvature of this ridge is much smaller than that of a smooth conical surface, resulting in a capillary driving force much greater than that of a smooth surface. Simultaneously, this ridge breaks the isotropy of the smooth conical surface, creating a low-energy flow path with a clear direction for the nutrient solution. Driven by the powerful directional capillary force, the nutrient solution is preferentially guided along this ridge to the microneedle tip and the entrance to the skin penetration channel, achieving a transformation from "isotropic disordered diffusion" to "anisotropic directional delivery." This effect requires only at least one ridge; therefore, even if only some microneedles in the wafer possess this structure, it can still exert a directional drainage effect. Second, significantly improved nutrient solution utilization: Through the aforementioned directional guidance, ineffective diffusion and waste of the nutrient solution on the substrate surface are effectively reduced, allowing more active ingredients to precisely enter the skin penetration channel, significantly improving the utilization efficiency of the nutrient solution. Third, it is independent of gravity and applicable to flexible postures: Because capillary force is much greater than gravity at the micrometer scale, the directional drainage function of this invention is independent of the wafer placement orientation. Whether the microneedle pierces the skin downwards, upwards, or tilted to the side, the nutrient solution can be precisely guided to the penetration channel under the directional capillary drive of the ridge, significantly improving the product's ease of operation and environmental adaptability. Fourth, it has high structural integration and good process compatibility: The tilted ridge is formed directly on the tilted surface of the microneedle, eliminating the need for additional guiding structures on the substrate surface, thus not increasing the wafer's manufacturing complexity and volume, and exhibiting good compatibility with existing microneedle etching processes.

[0012] Based on the above technical solution, the present invention can be further improved as follows: In one embodiment, the lowest point of the inclined ridge is located at the edge of the micropore. With this configuration, the ridge extends from the microneedle tip to the edge of the micropore, forming a continuous flow path from the micropore outlet to the microneedle tip. The nutrient solution flowing out of the micropore can be directly guided along the ridge towards the microneedle. This short and continuous flow path further reduces the retention and diffusion loss of the nutrient solution at the micropore outlet.

[0013] In one embodiment, the lowest point of the inclined ridge is located inside the micropore. A portion of the inclined ridge and a portion of the at least two inclined surfaces are formed on the inner wall of the micropore, while the other portion extends out of the micropore. This configuration allows a portion of the ridge to extend into the micropore, guiding the nutrient solution as it flows within the micropore. The entire process of the nutrient solution flowing in from the back of the micropore, through the micropore, and out from the front of the micropore is directionally guided, resulting in a longer flow path and more thorough guidance, further improving drainage efficiency.

[0014] In one embodiment, the inclined ridge formed on the inner wall of the micropore extends to the opening on the side of the micropore facing away from the microneedle tip. With this configuration, the ridge runs through the entire thickness direction of the micropore, extending from the back opening to the front outlet. The nutrient solution is capillarily guided by the ridge from the moment it enters the back opening of the micropore, and is continuously directed throughout its passage through the micropore until it flows out from the front and is guided towards the microneedle, achieving directional guidance throughout the entire process from the nutrient solution inlet to the permeation channel.

[0015] In one embodiment, all microneedles arranged circumferentially around the center of the micropore have at least two inclined surfaces, and the inclined ridges of each microneedle point towards the center of the micropore. This configuration ensures that all microneedles around the micropore have directional drainage capabilities, effectively guiding the nutrient solution flowing from the micropore in all circumferential directions. This achieves omnidirectional and uniform distribution of the nutrient solution, avoiding localized insufficient nutrient supply caused by some microneedles lacking guiding structures, and further improving the uniformity of drug delivery.

[0016] In one embodiment, the micropore is a circular hole, and among the multiple microneedles arranged circumferentially around the center of the micropore, the distance between any two adjacent microneedles is smaller than the diameter of the micropore. This arrangement allows the edge of the micropore to expand into the gap between adjacent microneedles, enabling the creation of sufficiently large-diameter micropores within a limited substrate area. This ensures the flow rate of the nutrient solution and prevents flow restriction or blockage due to excessively small micropore diameters.

[0017] In one embodiment, the number of micropores is at least two, with at least two micropores arranged adjacent to each other. Within the microneedle array surrounding each of the two adjacent micropores, two microneedles are shared by the two adjacent micropores. Four microneedles are arranged circumferentially around the center of each micropore, with one micropore positioned between the centers of any four adjacent microneedles. This arrangement, with four microneedles circumferentially arranged around the center of a micropore, forms a basic unit. In the case of multiple micropores, adjacent basic units share two microneedles, forming a highly compact array topology. This structure ensures that each micropore is fully surrounded by microneedles while minimizing the total number of microneedles, reducing manufacturing costs, and maximizing the density of micropores on the substrate.

[0018] In one embodiment, the surface of the inclined ridge has a micro-roughened structure, which consists of periodic or non-periodic depressions formed on the surface of the inclined ridge along its extension direction. The length of the depressions along the extension direction of the inclined ridge is greater than their lateral width, and the depressions form elongated groove structures on the surface of the inclined ridge. This configuration increases the actual surface area of ​​the ridge surface, allowing it to adhere to and carry more nutrient solution. Simultaneously, the protrusions and depressions along the extension direction of the ridge form micro-nano-level grooves on the ridge surface aligned with the ridge direction. These grooves provide additional capillary channels, consistent with the capillary conduction direction of the ridge itself. The combination of these features further enhances the directional flow efficiency of the nutrient solution along the ridge and the flow rate per unit time.

[0019] In one embodiment, as the inclined ridge extends from the micropore toward the tip of the microneedle, the included angle of the cross-section of the inclined ridge gradually increases; the included angle is the intersection angle of the at least two inclined surfaces on the cross-section of the inclined ridge. This configuration results in a smaller included angle and a sharper ridge near the micropore, generating a stronger capillary driving force at that location. This facilitates the rapid capture of the nutrient solution flowing from the micropore and its introduction into the ridge's flow path. As the ridge extends toward the needle tip, the included angle gradually increases and the ridge gradually becomes gentler, weakening the capillary driving force. This reduces the flow rate of the nutrient solution near the needle tip, allowing for a smooth and thorough release of the nutrient solution at the penetration channel formed by the needle tip piercing the skin, preventing excessive flow rate from causing liquid accumulation at the entrance of the penetration channel or diffusion and loss to the skin surface.

[0020] In one embodiment, the substrate has a thickness of 300 to 750 μm, and the micropores have a pore size of 0.1 to 3.5 mm. These parameter ranges are preferred ranges determined after comprehensively considering factors such as the required depth of microneedle penetration, the required flow rate of the nutrient solution, and the structural strength of the substrate. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1 This is a three-dimensional structural schematic diagram of an embodiment of the water-light microneedle wafer of the present invention; Figure 2 for Figure 1 The diagram shows a top view of the water-optic microneedle wafer. Figure 3 for Figure 1 A schematic cross-sectional view of the water-optic microneedle wafer is shown. Figure 4 This is a schematic diagram of a structure in one embodiment of the present invention, showing an inclined ridge extending to the edge of a micropore; Figure 5 This is a schematic diagram of a structure in one embodiment of the present invention, showing an inclined ridge extending to the inside of a micropore; Figure 6 This is a top view schematic diagram of a plurality of micropores arranged adjacently and sharing a microneedle in one embodiment of the present invention; Figure 7 This is a schematic diagram of a micro-roughened structure on the inclined ridge surface of a microneedle according to an embodiment of the present invention.

[0023] The markings in the diagram are explained as follows: 1—Substrate; 2—Microneedle; 21—First inclined surface; 22—Second inclined surface; 23—Inclined ridge; 24—Protrusion; 25—Depression; 3—Micropore; 31—Inner wall of micropore; 4—Microneedle tip. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0025] In the description of this invention, the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "setting," and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0027] Please see Figures 1 to 3 The first embodiment of the present invention provides a water-light microneedle wafer, including a substrate 1 and a microneedle array disposed on the substrate 1. A microhole 3 penetrating the substrate 1 is formed on the substrate 1, and the microhole 3 is used to allow nutrient solution to flow from the back side to the front side of the substrate 1. The microneedle array is formed on the front side of the substrate 1, and the microneedle array is composed of multiple microneedles 2, some of which are arranged circumferentially around the center of the microhole 3.

[0028] Among the multiple microneedles 2 arranged circumferentially around the center of the micropore 3, each has a first inclined surface 21 and a second inclined surface 22 (i.e., at least two inclined surfaces) on the side facing the micropore 3. The first inclined surface 21 and the second inclined surface 22 intersect on the side of the microneedle 2 facing the micropore 3, forming an inclined ridge line 23. This inclined ridge line 23 starts from the tip (microneedle tip 4) of the microneedle 2, extends from the surface of the microneedle 2 facing the micropore 3 towards the edge or interior of the micropore 3, and its projection on the plane of the substrate 1 points to the geometric center of the micropore 3 (in this embodiment, the micropore 3 is a circular hole, and the center is the center of the circle). This ridge line is different from the piercing ridge line that extends axially in traditional microneedles. The ridge line of this invention guides the nutrient solution from the outlet of the micropore 3 to the tip of the microneedle 2.

[0029] In this embodiment, four microneedles 2 are arranged circumferentially around the center of the micropore 3. The four microneedles 2 are evenly distributed around the micropore 3, and the included angle between two adjacent microneedles 2 is approximately 90°. Each microneedle 2 has the aforementioned first inclined surface 21, second inclined surface 22, and an inclined ridge line 23 formed by the intersection of the two, and the inclined ridge line 23 of each microneedle 2 points towards the center of the micropore 3.

[0030] When multiple microneedles 2 arranged circumferentially around the micropore 3 all have inclined ridges 23 pointing towards the center of the micropore 3, the inclined ridges 23 all point towards the center of the micropore 3 from different directions, forming a radial converging flow guiding network. The nutrient solution flowing out of the micropore 3 is guided to the tip of the microneedle 2 in all circumferential directions by the ridges, realizing all-round convergent drug delivery and avoiding the liquid diversion problem caused by the dispersion of the ridge direction.

[0031] This embodiment describes a preferred embodiment in which all microneedles 2 have inclined ridges 23. It should be understood that, based on the technical principles of this invention, among the multiple microneedles 2 arranged circumferentially around the micropore 3, only at least one microneedle 2 needs to have the aforementioned inclined ridge 23 structure to produce a directional capillary drainage effect, because a single ridge can break the isotropy of the smooth conical surface and provide a directional capillary driving force. Based on this, those skilled in the art can reasonably expect that a scheme in which only some microneedles 2 are provided with the inclined ridge 23 can also achieve the directional drainage function. This embodiment is described in the preferred form where all microneedles 2 have this structure, and does not constitute a limitation on the scope of protection of this invention.

[0032] In this embodiment, the microneedle chip is pressed onto the skin surface, and the microneedles 2 pierce the stratum corneum to form tiny penetration channels. Nutrient solution is supplied from the back of the substrate 1 to the micropores 3, passing through the micropores 3 and reaching the front of the substrate 1. At the micrometer scale, capillary action is far greater than gravity; therefore, the directional flow guidance function of this embodiment does not depend on the placement orientation of the chip. Whether the microneedles 2 are pointing downwards, upwards, or tilted laterally, because the side of the microneedles facing the micropores 3 has an inclined ridge 23 formed by the intersection of a first inclined surface 21 and a second inclined surface 22, and this inclined ridge 23 points towards the center of the micropores 3, the nutrient solution, after flowing out of the micropores 3, is preferentially guided along the inclined ridge 23 to the tip of the microneedles 2 and even to the entrance of the penetration channel formed by the microneedles 2 piercing the skin, and thus enters the skin.

[0033] In this invention, the "center of the micropore" refers to the geometric center point of the micropore 3 in the plane of the substrate 1 (the center of the circle when the micropore 3 is a circular hole, and the intersection of the diagonals or the centroid when the micropore 3 is a polygonal hole). The inclined edge 23 "pointing towards the center of the micropore 3" means that the projection of the extension direction of the inclined edge 23 onto the plane of the substrate 1 points towards the geometric center point of the micropore 3; that is, the inclined edge 23 extends from the tip of the microneedle 2 towards the geometric center of the micropore 3. In this invention, the "inclined edge 23" refers to a linear edge structure formed by the intersection of two inclined surfaces, extending from the tip of the microneedle 2 towards the center of the micropore 3, with an overall inclined orientation.

[0034] At the micrometer scale, capillary action is dominant, and gravity is negligible (Bond number Bo << 1). The capillary driving force of a liquid on a solid surface is closely related to the radius of curvature of the surface—the smaller the radius of curvature, the greater the capillary driving force. In this invention, the ridge formed by the intersection of the two inclined surfaces of the microneedle 2 facing the micropore 3 has a radius of curvature much smaller than that of a smooth conical surface (the ridge is a sharp edge, and its radius of curvature approaches zero). Therefore, the capillary driving force generated at the ridge is much greater than that of a smooth conical surface. More importantly, the ridge has a clear directionality (pointing towards the center of the micropore 3), which breaks the isotropy of the smooth conical surface and creates a directional flow path for the nutrient solution with a lower energy state. Since the capillary force is much greater than gravity, the directional flow function of this invention does not depend on the placement orientation of the wafer. Regardless of whether the microneedle 2 is facing down (the standard usage position), facing up, or tilted to the side, the nutrient solution, driven by a strong directional capillary force, is forcibly guided from the micropore 3 to the tip of the microneedle 2 and the entrance to the skin penetration channel along the tilted ridge 23, achieving directional drainage independent of gravity. This is fundamentally different from the existing mechanism of smooth conical surfaces that rely on gravity or isotropic spreading.

[0035] It should be noted that although multi-faceted pyramidal microneedles (such as triangular pyramids, square pyramids, or star-shaped pyramids) exist in the prior art, their edges all extend along the microneedle axis, and their function is to enhance the microneedle's ability to pierce the skin or improve structural strength. These edges are neither located on the side of the microneedle facing the micropore 3 nor pointing towards the center of the micropore 3, therefore they do not have the function of guiding the nutrient solution from the micropore 3 to the microneedle tip. The inclined edges 23 of this invention start from the needle tip and extend towards the micropore 3, functionally realizing a transformation from 'mechanical piercing' to 'liquid guidance', which is fundamentally different from the prior art.

[0036] This invention offers the following advantages: First, directional capillary drainage: The two inclined surfaces of the microneedle 2 facing the micropore 3 intersect to form a ridge. The radius of curvature of this ridge is much smaller than that of a smooth conical surface, resulting in a capillary driving force much greater than that of a smooth surface. Simultaneously, this ridge breaks the isotropy of the smooth conical surface, creating a low-energy flow path with a clear direction for the nutrient solution. Driven by the strong directional capillary force, the nutrient solution is preferentially guided along this ridge to the tip of the microneedle 2 and the entrance to the skin penetration channel, achieving a transformation from "isotropic disordered diffusion" to "anisotropic directional delivery." This effect requires only at least one ridge; therefore, even if only some of the microneedles 2 in the wafer possess this structure, it can still exert a directional drainage effect. Second, significantly improved nutrient solution utilization: Through the aforementioned directional guidance, ineffective diffusion and waste of the nutrient solution on the surface of the substrate 1 are effectively reduced, allowing more active ingredients to accurately enter the skin penetration channel, significantly improving the utilization efficiency of the nutrient solution. Third, it is independent of gravity and applicable to flexible postures: Since capillary force is much greater than gravity at the micrometer scale, the directional drainage function of this invention is independent of the placement direction of the wafer. Whether the microneedle 2 pierces the skin downwards, is used upwards, or is tilted to the side, the nutrient solution can be precisely guided to the penetration channel under the directional capillary drive of the ridge, significantly improving the product's ease of operation and environmental adaptability. Fourth, it has high structural integration and good process compatibility: The tilted ridge 23 is directly formed on the tilted surface of the microneedle 2, eliminating the need to add additional guiding structures on the surface of the substrate 1, without increasing the manufacturing complexity and volume of the wafer, and has good compatibility with existing microneedle 2 etching processes.

[0037] Please see Figure 4 The second embodiment of the present invention provides a water-light microneedle wafer, which differs from the first embodiment in that the lowest point of the inclined ridge 23 is located at the edge of the micropore 3.

[0038] Specifically, in this embodiment, the inclined ridge line 23 formed by the intersection of the first inclined surface 21 and the second inclined surface 22 on the side of the microneedle 2 facing the microhole 3 extends from the tip of the microneedle 2 to the edge of the microhole 3, that is, the lowest point of the inclined ridge line 23 falls exactly at the edge of the front outlet of the microhole 3.

[0039] In this configuration, the inclined ridge 23 forms a continuous flow path from the tip of the microneedle 2 to the edge of the micropore 3. After the nutrient solution flows out of the micropore 3, it contacts the lowest point of the inclined ridge 23 at the edge of the micropore 3, and is then guided along the inclined ridge 23 towards the tip of the microneedle 2 under the drive of directional capillary force. Compared to the first embodiment where the inclined ridge 23 starts at the tip and ends at the root of the microneedle near the micropore 3, in this embodiment the inclined ridge 23 extends further to the edge of the micropore 3, making the flow path shorter and more direct. This reduces the residence time of the nutrient solution at the outlet of the micropore 3, further reducing the disordered diffusion loss of the nutrient solution before reaching the ridge. The other structures and working principles of this embodiment are the same as those of the first embodiment, and will not be repeated here.

[0040] Please see Figure 5 The third embodiment of the present invention provides a water-light microneedle wafer, which differs from the first embodiment in that: the lowest point of the inclined ridge 23 is located inside the micropore 3, and a portion of the inclined ridge 23, the first inclined surface 21, and the second inclined surface 22 are formed on the inner wall 31 of the micropore 3, while the other portion extends out of the micropore 3.

[0041] Specifically, in this embodiment, the inclined ridge 23 formed by the intersection of the first inclined surface 21 and the second inclined surface 22 on the side of the microneedle 2 facing the micropore 3 extends not only from the tip of the microneedle 2 towards the center of the micropore 3, but also further into the interior of the micropore 3. That is, a portion of the inclined ridge 23 is located outside the micropore 3 (from the tip of the microneedle 2 to the front exit of the micropore 3), and another portion is located inside the micropore 3 (formed on the inner wall 31 of the micropore 3). Correspondingly, a portion of the first inclined surface 21 and the second inclined surface 22 are also formed on the inner wall 31 of the micropore 3.

[0042] With this configuration, a portion of the inclined ridge 23 extends into the interior of the micropore 3, allowing the nutrient solution to begin receiving directional capillary guidance from the inclined ridge 23 as it flows within the micropore 3. In other words, after the nutrient solution enters the micropore 3 from the back of the substrate 1, it is directionally guided along the portion of the inclined ridge 23 formed on the inner wall 31 of the micropore 3 as it passes through the micropore 3. After the nutrient solution flows out from the front outlet of the micropore 3, it continues to be guided along the inclined ridge 23 on the outside of the micropore 3 towards the tip of the microneedle 2. The entire process from the nutrient solution entering the micropore 3 to being delivered to the permeation channel of the microneedle 2 is directionally guided by the inclined ridge 23, resulting in a longer flow path and more thorough guidance. The other structures and working principles of this embodiment are the same as those of the first embodiment and will not be repeated here.

[0043] The fourth embodiment of the present invention provides a water-light microneedle wafer, which is a further improvement on the third embodiment. The difference between the third embodiment and the third embodiment is that the inclined ridge line 23 formed on the inner sidewall 31 of the microhole 3 extends to the side opening of the microhole 3 facing away from the microneedle tip (i.e., the back opening of the microhole 3).

[0044] Specifically, in this embodiment, the inclined ridge 23 extends from the tip of the microneedle 2 toward the center of the micropore 3, enters the interior of the micropore 3, and continues to extend along the inner sidewall 31 of the micropore 3 until it reaches the back opening of the micropore 3. That is, the inclined ridge 23 runs through the entire thickness direction of the micropore 3, extends from the back opening of the micropore 3 to the front exit of the micropore 3, and further extends to the tip of the microneedle 2.

[0045] The first inclined surface 21 and the second inclined surface 22 are also partially formed on the inner wall 31 of the micropore 3 and extend from near the back opening of the micropore 3 to the outside of the micropore 3. In other words, the first inclined surface 21, the second inclined surface 22 and the inclined ridge line 23 together form a continuous flow guiding structure from the back opening of the micropore 3 through the interior of the micropore 3 to the microneedle 2.

[0046] With this configuration, the nutrient solution, upon entering the back opening of the micropore 3 from the back of the substrate 1, immediately contacts the lowest point of the inclined ridge 23. Driven by directional capillary force, it is then guided along the inclined ridge 23 through the entire micropore 3, and continues to be guided along the inclined ridge 23 outside the micropore 3 towards the tip of the microneedle 2. Compared to the third embodiment where the inclined ridge 23 only partially extends into the micropore 3, in this embodiment, the inclined ridge 23 penetrates the full thickness of the micropore 3, achieving directional guidance throughout the entire flow path from the nutrient solution inlet to the permeation channel. This minimizes the diffusion and loss of the nutrient solution at each stage of the flow path, resulting in the highest drainage efficiency.

[0047] The other structures and working principles of this embodiment are the same as those of the third embodiment, and will not be repeated here.

[0048] Please see Figure 6 The fifth embodiment of the present invention provides a water-light microneedle wafer, which differs from the first embodiment in that: the number of micropores 3 is multiple, and the micropores 3 are circular holes; among the multiple microneedles 2 arranged circumferentially around the center of each micropore 3, the distance between any two adjacent microneedles 2 is less than the diameter of the micropore 3 they surround; at least two micropores 3 are arranged adjacently among the multiple micropores 3, and in the microneedle array surrounding each of the two adjacent micropores 3, two microneedles 2 are shared by the two adjacent micropores 3.

[0049] Specifically, in this embodiment, a plurality of micropores 3 are provided on the substrate 1. Each micropore 3 is a circular hole. A plurality of microneedles 2 are arranged circumferentially around the center of each micropore 3, and for each micropore 3, the distance between any two adjacent microneedles 2 arranged circumferentially around it is less than the diameter of the micropore 3. In this way, the boundary of the micropore 3 extends into the gap region between adjacent microneedles 2, so that micropores 3 with a sufficiently large aperture can be provided on a limited area of ​​the substrate 1.

[0050] Multiple micropores 3 are arranged in an array on the substrate 1. Taking two adjacent micropores 3 as an example, the first micropore is surrounded by a first microneedle array, and the second micropore is surrounded by a second microneedle array. In the first microneedle array and the second microneedle array, two microneedles 2 belong to both arrays simultaneously—that is, these two microneedles 2 surround both the first micropore and the second micropore, and are shared by the first micropore and the second micropore.

[0051] This configuration, where adjacent micro-holes 3 share micro-needles 2, allows for a more compact arrangement of the micro-needle array. More micro-holes 3 can be arranged on the same substrate area, or a multi-micro-hole layout can be achieved without increasing the overall wafer size, thus improving the utilization efficiency of the substrate area. Simultaneously, the shared micro-needles 2 also possess an inclined ridge 23 structure oriented towards the micro-holes they surround, enabling directional flow guidance for each micro-hole 3 they surround.

[0052] In this embodiment, the periphery of each micropore 3 can be provided with an inclined ridge line 23 structure as described in any of the schemes in the first to fourth embodiments, and the specific choice can be made according to actual needs.

[0053] The other structures and working principles of this embodiment are the same as those of the first embodiment, and will not be repeated here.

[0054] Please see Figure 6 The sixth embodiment of the present invention provides a water-light microneedle wafer, which is a further improvement on the fifth embodiment. The difference between the sixth and fifth embodiments is that: the number of microneedles 2 arranged circumferentially around the center of each micropore 3 is four; a micropore 3 is provided between the centers of any four adjacent microneedles 2; in any two adjacent micropores 3, there are two microneedles 2 shared by the two adjacent micropores 3 in the periphery microneedle array.

[0055] Specifically, in this embodiment, a plurality of micropores 3 are provided on the substrate 1. Four microneedles 2 are arranged circumferentially around the center of each micropore 3, and the four microneedles 2 are evenly distributed around the micropore 3. In the microneedle array of the substrate 1, a micropore 3 is provided between the centers of any four adjacent microneedles 2 (i.e., at the center of the quadrilateral region enclosed by these four microneedles 2). In other words, the micropore 3 is located at the center of the quadrilateral region enclosed by four adjacent microneedles 2, and the four microneedles 2 are respectively located in the four directions of the micropore 3 (such as up, down, left, and right), together surrounding the micropore 3.

[0056] In the case of multiple micropores 3, for any two adjacent micropores 3, two of the four microneedles 2 surrounding them are shared. For example, the first micropore has one microneedle 2 surrounding it in each of the four directions: top, bottom, left, and right; the second micropore is located to the right of the first micropore, and the second micropore also has one microneedle 2 surrounding it in each of the four directions: top, bottom, left, and right. The microneedle 2 on the right side of the first micropore is also the microneedle 2 on the left side of the second micropore, and the microneedles 2 at the upper right and lower right corners of the first micropore are also the microneedles at the upper left and lower left corners of the second micropore—that is, the two micropores 3 share two microneedles 2.

[0057] In this configuration, four microneedles 2 are arranged circumferentially around the center of a micropore 3, forming a basic unit. In the case of multiple micropores 3, adjacent basic units share two microneedles 2, forming a highly compact array topology. This structure ensures that each micropore 3 is fully surrounded by microneedles 2 while minimizing the total number of microneedles 2, reducing manufacturing costs, and maximizing the arrangement density of micropores 3 on the substrate 1.

[0058] In this embodiment, each microneedle 2 can be provided with an inclined ridge line 23 structure as described in any of the schemes in the first to fourth embodiments, and the specific choice can be made according to actual needs.

[0059] The other structures and working principles of this embodiment are the same as those of the fifth embodiment, and will not be repeated here.

[0060] In the above embodiments, the thickness of the substrate 1 is preferably 300 to 750 μm. The planar dimensions of the substrate 1 can be selected according to actual needs, for example, from 1 mm × 1 mm to 15 mm × 15 mm. The pore diameter of the micropore 3 is preferably 0.1 to 3.5 mm. The needle height of the microneedle 2 is preferably no greater than 1000 μm. The total number of microneedles 2 in the microneedle array can be selected according to actual needs. The above parameter ranges are preferred ranges determined after comprehensively considering factors such as the depth requirement of microneedle puncture into the skin, the flow rate requirement of nutrient solution, and the structural strength of the substrate, but the present invention is not limited thereto. The cross-sectional shape of the micropore 3 can be circular, square, polygonal, or any other suitable shape, which can be determined according to the manufacturing process and usage requirements.

[0061] Based on the above embodiments, a liquid storage cavity (not shown in the figure) can also be provided on the back side of the substrate 1. The liquid storage cavity is located on the back side of the substrate 1 and communicates with the micropore 3 for storing the nutrient solution to be introduced. The liquid storage cavity allows the nutrient solution to be pre-stored in the wafer, eliminating the need for an external liquid supply device during use, making it more convenient to use.

[0062] Based on the above embodiments, the inclined ridge line 23 can also have the following optimized design.

[0063] refer to Figure 7In one embodiment, the surface of the inclined ridge 23 is provided with a micro-rough structure, which is a periodic or non-periodic recess 25 formed along the extension direction of the inclined ridge 23. The length of the recess 25 along the extension direction of the inclined ridge 23 is greater than its lateral width, and the recess 25 forms a narrow groove structure on the surface of the inclined ridge 23. The ridge between two adjacent recesses 25 can be understood as a protrusion 24.

[0064] This design increases the actual surface area of ​​the ridge surface due to the micro-rough structure, allowing the ridge surface to adhere to and carry more nutrient solution. Simultaneously, the protrusions 24 and recesses 25, positioned along the ridge extension direction, form micro-nano-scale grooves on the ridge surface aligned with the ridge direction. These grooves provide additional capillary channels, consistent with the capillary conduction direction of the ridge itself. The combined effect of these two features further enhances the directional flow efficiency of the nutrient solution along the ridge and the flow rate per unit time. Preferably, the length of the protrusions 24 and recesses 25 along the inclined ridge 23 is greater than their lateral width, resulting in a narrow, elongated groove structure on the ridge surface. The capillary driving force experienced by the liquid within the grooves along the ridge direction is greater than that in the lateral direction, further ensuring the directionality of the flow. The dimensions of the protrusions 24 and recesses 25 are in the micrometer to nanometer range.

[0065] In one embodiment, the recess 25 is teardrop-shaped, and at least one end of the recess 25 extends along the inclined ridge 23, converging into a single point that coincides with the inclined ridge 23. This arrangement, with the tip of the teardrop-shaped recess coinciding with the ridge, ensures that capillary guidance is most concentrated at the tip when the liquid flows along the ridge, facilitating rapid capture and introduction of the liquid into the recess. The enlarged area of ​​the recess provides a larger liquid contact area, increasing the contact between the liquid and the ridge surface, thereby enhancing the continuity of capillary actuation. The smooth transition between the tip of the teardrop-shaped recess and the enlarged area allows the capillary driving force to gradually change along the flow direction, avoiding fluctuations in the liquid front propulsion velocity or local stagnation that may occur due to abrupt changes in cross-section.

[0066] It should be noted that when the protrusions 24 and depressions 25 of the micro-rough structure are arranged along the extension direction of the ridge, the direction of the capillary driving force they generate is consistent with the flow guiding direction of the ridge, which can produce a synergistic enhancement effect. Roughness increases the surface area, but it also increases the flow resistance (friction resistance). However, when the stronger capillary driving force near the micropore section introduces the nutrient solution into the ridge and establishes a continuous flow, even if the capillary driving force gradually weakens, the established flow continuity can still maintain the nutrient solution continuing to flow towards the needle tip.

[0067] In one embodiment, as the inclined ridge 23 extends from the micropore 3 toward the needle tip, the included angle of its cross-section gradually increases. The included angle refers to the angle at which the first inclined surface 21 and the second inclined surface 22 intersect on the cross-section of the ridge.

[0068] This design results in a smaller angle and sharper ridge near the micropore 3, generating a strong capillary driving force. This facilitates the rapid capture of the nutrient solution flowing from the micropore 3 and its introduction into the ridge's flow path. As the ridge extends towards the needle tip, the angle gradually increases and the ridge becomes gentler, weakening the capillary driving force. This reduces the flow velocity of the nutrient solution near the needle tip, allowing for a smooth and thorough release and penetration of the solution into the permeation channel formed by the needle piercing the skin. It prevents excessive flow velocity from causing the solution to accumulate and rebound at the entrance of the permeation channel or to diffuse and leak onto the skin surface. Once the strong capillary driving force near the micropore introduces the nutrient solution into the ridge and establishes a continuous flow, the established flow continuity can be maintained even as the capillary driving force gradually weakens along the path, ensuring the nutrient solution continues to flow towards the needle tip. The gradual change in angle ensures a smooth transition of capillary driving force, avoiding flow instability caused by abrupt changes in driving force.

[0069] The water-light microneedle wafers of the above embodiments of the present invention can be integrally manufactured on a silicon substrate using semiconductor microfabrication techniques (such as photolithography and etching). Specifically, micro-holes 3 can be formed on the substrate 1 first, and then microneedles 2 with inclined surfaces can be etched around the micro-holes 3, so that the inclined ridges 23 of the microneedles 2 point towards the center of the micro-holes 3. Alternatively, the wafers can be manufactured by first etching the microneedles 2 and then creating the micro-holes 3. The specific steps of the manufacturing method can be determined according to the actual process conditions, and the present invention does not limit them. The water-light microneedle wafers provided by the present invention can be widely used in medical aesthetics, skin drug delivery, vaccine delivery and other fields, and are especially suitable for beauty and skin care scenarios such as water-light injection and serum infusion, and have broad industrial application prospects.

[0070] Although the invention has been described with reference to several typical embodiments, it should be understood that the terminology used is illustrative and exemplary, and not restrictive. Since the invention can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A water-light microneedle wafer, comprising a substrate and a microneedle array disposed on the substrate, wherein the substrate has at least one micropore penetrating the substrate, the micropore being used for the flow of nutrient solution, characterized in that, Among the multiple microneedles arranged circumferentially around the center of the micropore, at least one of the microneedles has at least two inclined surfaces on the side facing the micropore. The at least two inclined surfaces intersect on the side of the microneedle facing the micropore, forming an inclined ridge line that extends from the tip of the microneedle toward the edge or interior of the micropore and points toward the center of the micropore.

2. The water-light microneedle wafer according to claim 1, characterized in that, The lowest point of the inclined ridge is located at the edge of the micropore.

3. The water-light microneedle wafer according to claim 1, characterized in that, The lowest point of the inclined ridge is located inside the micropore. A portion of the inclined ridge and the at least two inclined surfaces are formed on the inner wall of the micropore, while the other portion extends out of the micropore.

4. The water-light microneedle wafer according to claim 3, characterized in that, The inclined ridge formed on the inner wall of the micropore extends to the opening on the side of the micropore facing away from the tip of the microneedle.

5. The water-light microneedle wafer according to any one of claims 1 to 4, characterized in that, All microneedles arranged circumferentially around the center of the micropore have at least two inclined surfaces, and the inclined ridges of each microneedle point towards the center of the micropore.

6. The water-light microneedle wafer according to claim 5, characterized in that, The micropore is a circular hole, and among the multiple microneedles arranged circumferentially around the center of the micropore, the distance between any two adjacent microneedles is less than the diameter of the micropore.

7. The water-light microneedle wafer according to claim 6, characterized in that, The number of micropores is at least two, and at least two of the micropores are arranged adjacent to each other. In the microneedle array surrounding each of the two adjacent micropores, two microneedles are shared by the two adjacent micropores. The number of microneedles arranged circumferentially around the center of each micropore is four, and a micropore is provided between the centers of any four adjacent microneedles.

8. The water-light microneedle wafer according to claim 1, characterized in that, The surface of the inclined ridge is provided with a micro-rough structure, which is a periodic or non-periodic depression formed on the surface of the inclined ridge along the extension direction of the inclined ridge; the length of the depression along the extension direction of the inclined ridge is greater than its lateral width, and the depression forms a narrow groove structure on the surface of the inclined ridge.

9. The water-light microneedle wafer according to claim 1, characterized in that, As the inclined ridge extends from the micropore toward the tip of the microneedle, the included angle of the cross section of the inclined ridge gradually increases; the included angle is the intersection angle of the at least two inclined surfaces on the cross section of the inclined ridge.

10. The water-light microneedle wafer according to claim 1, characterized in that, The substrate has a thickness of 300 to 750 μm, and the micropores have a pore size of 0.1 to 3.5 mm.

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