Optical member and method of manufacturing the same

Abstract

To provide an optical member which enables high-resolution biological observation over a wide range for a long time while minimizing damage to a living body.SOLUTION: An optical member 100 of the present invention is designed to be installed on a surface 10a of a living body 10 and used to observe the inside of the living body 10, and comprises a biocompatible first resin film 101 and a light-transmissive second resin film 102 formed on one surface of the first resin film, where a difference in refractive index between the first resin film 101 and the living body 10 is 0.4 or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an optical member and a method for producing the same. [Background technology]

[0002] Observation of the inside of a living organism using a microscope is carried out through an optical member placed on the surface of the area to be observed (Non-Patent Document 1, etc.). Plates made of highly refractive materials such as glass and silicon are used for the optical members, but there is a demand for the development of new optical members that enable observation with higher resolution.

[0003] Generally, the surface of a living body has a curved shape and its curvature is constantly changing, making it difficult to bring these optical components into contact without gaps over a wide area for a long period of time, limiting the area and time that can be observed.

[0004] It is also necessary to consider damage to the living body caused by contact with the optical members, especially damage to the living body caused by pressure from the contacting optical members. A damaged living body will be inflamed or bleed, which will deteriorate the light collection from the living body and make it difficult to observe the true state of the living body. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Kawakami, R., Sawada, K., Kusama, Y., Fang, Y.-C., Kanazawa, S., Kozawa, Y., Sato, S., Yokoyama, H., & Nemoto, T. (2015). In vivo two-photon imaging of mouse hippocampal neurons in dentate gyrus using a light source based on a high-peak power gain-switched laser diode. Biomedical Optics Express, 6(3), 891. https: / / doi.org / 10.1364 / BOE.6.000891 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide an optical component and a manufacturing method thereof that enable high-resolution biological observation over a wide area and for a long period of time while minimizing damage to the living body. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention employs the following means.

[0008] (1) An optical element according to one embodiment of the present invention is an optical element that is placed on the surface of a living body and used to observe the inside of the living body, comprising a first resin film that is biocompatible and a second resin film that is formed on one side of the first resin film and has optical transparency, wherein the refractive index difference between the first resin film and the living body is 0.4 or less.

[0009] (2) In the optical member described in (1) above, the first resin film may include a base portion having a refractive index difference of 0.4 or less with respect to the living body, and the biocompatible structure portion.

[0010] (3) In the optical member described in either (1) or (2) above, the second resin film preferably has a refractive index difference of 0.4 or less with respect to the living body.

[0011] (4) In the optical member described in any one of (1) to (3) above, it is preferable that the living body is an animal brain, and the first resin film and the second resin film have refractive indices of 1.3 or more and 1.4 or less.

[0012] (5) A method for manufacturing an optical element according to one embodiment of the present invention is a method for manufacturing an optical element described in any one of (1) to (4) above, comprising a resin film attachment step of attaching the first resin film to the observation area, a resin application step of applying a liquid curable resin to a surface of the first resin film opposite the observation area, and a resin curing step of curing the applied curable resin.

[0013] (6) The method for producing an optical member according to (5) above preferably further comprises a resin film bonding step of bonding an end of the first resin film to an outer periphery of the observation region. Effect of the Invention

[0014] According to the present invention, it is possible to provide an optical member and a manufacturing method thereof that enable high-resolution biological observation over a wide area for a long period of time while minimizing damage to the biological body. [Brief description of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view showing an optical member according to an embodiment of the present invention fabricated on the surface of a living brain. [Diagram 2] 2 is an enlarged cross-sectional view of a portion of the optical member of FIG. 1. [Diagram 3] FIG. 2 is a plan view illustrating a schematic example of the configuration of the first resin film in FIG. [Figure 4] 3(a) to 3(d) are cross-sectional views illustrating states in each step of the method for producing an optical member according to the embodiment. [Diagram 5]4(a) to 4(c) are photographs of a mouse brain observed through the optical member of Example 1. [Figure 6] 6(a) to 6(c) are photographs of a mouse brain observed through the optical member of Example 2. [Figure 7] FIG. 13 is a cross-sectional view showing a schematic configuration of an experimental sample for biological observation using the resin films of Examples 3 and 4. [Figure 8] 13(a) and 13(b) are graphs comparing the full width at half maximum (FWHM) obtained from the distribution of the spread of fluorescence obtained at depths of 200 μm, 500 μm, and 1000 μm in Example 3. [Figure 9] 13(a) and 13(b) are graphs comparing the full width at half maximum (FWHM) obtained from the distribution of the spread of fluorescence obtained at depths of 200 μm, 500 μm, and 1000 μm in Example 4. [Figure 10] (a) to (c) are images, obtained by immunostaining, of a cross section of a brain in which the optical element of Example 5 was placed. (d) to (f) are images, obtained by immunostaining, of a cross section of a brain in which the resin film of Comparative Example 1 was placed. [Figure 11] 13 shows images of mouse cerebral nerve cells visualized at three magnifications, observed using the optical element of Example 6. [Figure 12] 13 is an image showing visualization of nerve cells in the cerebral cortex, midbrain, and cerebellum of a mouse observed using the optical element of Example 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an optical member according to an embodiment of the present invention and a manufacturing method thereof will be described in detail with reference to the drawings. Note that the drawings used in the following description may show characteristic parts in an enlarged scale for the sake of convenience in order to make the characteristics easier to understand, and the dimensional ratios of each component may not necessarily be the same as in reality. In addition, the materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited thereto, and may be appropriately modified and implemented within the scope of the present invention.

[0017] [Optical components] Fig. 1 is a cross-sectional view showing a state in which an optical member 100 according to an embodiment of the present invention is placed on a surface 10a of a living body (here, a brain) 10. Fig. 2 is a cross-sectional view showing an enlarged view of a portion R of the optical member of Fig. 1. The optical member 100 is an optical member (optical observation window) manufactured (placed) on the surface of the living body 10 and used to observe the inside of the living body 10, and mainly comprises a first resin film 101 and a second resin film 102 formed on one surface (main surface) 101a of the first resin film 101.

[0018] The first resin film 101 is a polymer film and has biocompatibility (bioprotection). The first resin film 101 (nanosheet, etc.) formed thin is preferable because it has excellent adhesion and flexibility. The thickness of the first resin film 101 is not particularly limited, but is preferably about 10 nm to 1 cm. For example, when the living body is a mouse brain, it is preferably about 10 nm to 200 nm. In this embodiment, biocompatibility means a property that does not harm or does not greatly harm the physiological function of a living body even when it comes into contact with the living body. In this embodiment, the living body means a part or the whole of the body of an organism, and is preferably in a living state or a state close to that. The type of organism here is not particularly limited, and examples thereof include vertebrates such as mammals including humans, invertebrates, and plants.

[0019] Due to its high adhesiveness and flexibility, the first resin film 101 can be deformed to follow the surface shape of the living body 10, and can be attached without leaving any gaps even to curved shapes and surfaces with irregularities. This function does not change even if the attachment region (area) is expanded, so it is possible to manufacture an optical member 100 provided with a large-area first resin film 101 and observe a wide range of the living body surface.

[0020] The other surface (main surface) 101b of the first resin film 101 becomes the surface that comes into contact with the living body 10. The first resin film 101 has biocompatibility at least in the vicinity of the other surface 101b. When the second resin film 102 is directly attached to the living body without the first resin film 101, inflammation may occur in the attached area, but when the first resin film 101 is sandwiched between the first resin film 101 and the second resin film 102, the occurrence of this inflammation can be suppressed.

[0021] Furthermore, the first resin film 101 has high optical transparency, and can collect (transmit) light arriving from the living body 10 without degradation, and can allow the light to reach a microscope (not shown), thereby realizing high-resolution living body observation. The high optical transparency is due to the refractive index of the material constituting the first resin film 101, and the first resin film 101 is made of a material with a low refractive index close to the refractive index of the living body 10 to be contacted. The refractive index difference between the first resin film 101 and the living body 10 is preferably 0.4 or less, more preferably 0.2 or less, and even more preferably 0.05 or less. When the living body 10 to be contacted is an animal brain, the refractive index of the first resin film 101 is preferably in the range of 1.3 to 1.4, and more preferably 1.33 to 1.37.

[0022] Examples of materials for the first resin film 101 include fluororesins such as CYTOP (registered trademark) and PTFA, PLLA, PDMS, PLGA, etc. The first resin film 101 can be manufactured using a known film formation technique such as vacuum film formation.

[0023] The first resin film 101 may be a base material made of a low refractive index material as described above, or may be a base material to which a structure having biocompatibility has been added in terms of contact with the living body 10. This structure may be a hydrophilic structure. FIG. 3 is a plan view showing a schematic example of the configuration of the first resin film 101A (101) having a hydrophilic structure. The first resin film 101A is composed of a base (base material) 103 made of a low refractive index material such as fluororesin, and a structure (hydrophilic structure) 104 formed on the side of the base 103 that is to be in contact with the living body 10. The refractive index difference between the base 103 and the living body 10 is preferably 0.4 or less, more preferably 0.2 or less, and even more preferably 0.05 or less.

[0024] As an example of the hydrophilic structure 104, as shown in Fig. 3, it is possible to use one that is composed of a PDMS (polydimethylsiloxane) film 105 formed on the surface of the base 103 and a plurality of chain-like PEO (polyethylene oxide) molecules 106 with one end bonded to the PDMS film 105. The refractive index of the PDMS film 105 is higher than that of fluororesin, but by forming it sufficiently thin, it is possible to almost completely eliminate the effect on light collection. The first resin film 101A in which the base 103 is composed of CYTOP may be referred to as a PEO-PDMS-CYTOP sheet below.

[0025] The second resin film 102 is formed on one surface of the first resin film 101, and has enough optical transparency to collect (transmit) light arriving from the living body 10 through the first resin film 101 without degradation and to allow the light to reach a microscope (not shown). The second resin film 102 is a film formed by curing a curable resin under predetermined conditions, and has the function of covering and protecting one surface 101a of the first resin film 101 and strongly fixing the first resin film 101 to the living body surface. Examples of the curable resin include a photocurable resin that is cured by irradiation with light such as UV light, a thermosetting resin that is cured by heating, and a chemical reaction type curable resin that is cured by mixing two liquids (resin (base) and curing agent).

[0026] Although the first resin film 101 itself has an adhesive function to the surface of the living body, it is difficult to maintain the adhesive state for a long period of time. Therefore, the first resin film 101 is fixed by covering it with the second resin film 102. Specifically, the center of the second resin film 102 is adhered to one surface 101a of the first resin film, and the outer periphery of the second resin film 102 is adhered to the outer periphery (here, the skull 10A) 12 of the observation region 11 of the living body or to an adhesive 107 applied to the outer periphery 12. This makes it possible to maintain the contact state of the first resin film 101 with the observation region 11 for a long period of time.

[0027] The outer surface (top surface) 102a of the second resin film 102 (opposite to the first resin film 101) is preferably as flat as possible from the viewpoint of allowing light to reach a microscope (not shown) placed directly above. Therefore, the second resin film 102 preferably has a thickness sufficient to absorb the curvature and unevenness of the first resin film 101 that is formed by following the shape of the surface of a living body, and is preferably 100 μm or more when used for observing the cerebral cortex of a mouse brain, for example. However, from the viewpoint of suppressing deterioration of light collection, the thinner the film, the more preferable it is, and the thickness of the second resin film 102 at least in the light collection region directly under the microscope is preferably 1 mm or less when used for observing the brain of an animal such as a mouse.

[0028] The refractive index of the second resin film 102 is preferably in a range of 0.4 or less, more preferably 0.2 or less, and even more preferably 0.05 or less, such that the difference in refractive index between the second resin film 102 and the living body 10 is 0.2 or less, and even more preferably 0.05 or less. For example, when used to observe the brain of an animal such as a mouse, the refractive index of the second resin film 102 is preferably in a range of 1.3 to 1.4, and more preferably 1.33 to 1.37. Examples of materials for the photocurable resin that forms the second resin film 102 include, for example, fluorine-based resins, BIO-133 (manufactured by MY POLYMER), BIO-134 (manufactured by MY POLYMER), NOA133 (manufactured by Norland Products), NOA136 (manufactured by Norland Products), NOA135826 (manufactured by Norland Products), NOA61 (manufactured by Norland Products), NOA81 (manufactured by Norland Products), NOA83H (manufactured by Norland Products), KER-4000-UV (manufactured by Shin-Etsu Chemical Co., Ltd.), FE-90-UV (manufactured by Shin-Etsu Chemical Co., Ltd.), and the like.

[0029] Examples of the thermosetting resin material that forms the second resin film 102 include ER-2315 (manufactured by Sankyo Pharmaceutical Co., Ltd.), ER-2233 (manufactured by Sankyo Pharmaceutical Co., Ltd.), EH-2002 (manufactured by Sankyo Pharmaceutical Co., Ltd.), EH-2485 (manufactured by Sankyo Pharmaceutical Co., Ltd.), polyester, acrylic resin, epoxy resin, silicone resin, melamine resin, benzoguanamine resin, etc. Examples of the chemical reaction type curable resin that forms the second resin film 102 include LOCTITE EA E-30CL (manufactured by Henkel), LOCTITE Quick Mix (manufactured by Henkel), TM2086M (manufactured by ThreeBond), TM2086N (manufactured by ThreeBond), TM2086T (manufactured by ThreeBond), 3M Scotch-Weld DP110 (manufactured by 3M), KE-103 (manufactured by Shin-Etsu Chemical Co., Ltd.), KE-108 (manufactured by Shin-Etsu Chemical Co., Ltd.), KE-1012-A / B (manufactured by Shin-Etsu Chemical Co., Ltd.), KE-1051J-A / B (manufactured by Shin-Etsu Chemical Co., Ltd.), epoxy-based resins, silicone-based resins, and the like.

[0030] [Method of manufacturing optical components] 4(a) to (d) are cross-sectional views showing the states of each step in the method for producing an optical member of this embodiment. The method for producing an optical member mainly includes a resin film attachment step, a resin application step, and a resin curing step, and may further include a bonding step. Here, the case of producing an optical member for observing the brain of a living organism is illustrated as an example.

[0031] (Resin film attachment process) As shown in Fig. 4(a), a part of the skull 10A is removed to make an opening, exposing the observation region 11 of the brain, and then a first resin film 101 is attached to the exposed brain and its surroundings so as to cover the observation region 11. The first resin film 101 is brought into contact with every corner of the opening, including the stepped portions, so as to leave no gaps. The first resin film 101 is large enough to completely cover the observation region 11 with some excess, for example, the area of ​​the main surface is 110% or more of the area of ​​the observation region.

[0032] (Resin film adhesion process) Although not essential, as shown in FIG. 4(b), it is preferable to apply adhesive 107 to the outer periphery 12 of the observation region (opening of skull 10A) 11 and adhere the end 101c of the first resin film 101 to the outer periphery 12. This adhesion can seal the gap between the first resin film 101 and the surface 10a of the living body (brain) so that the curable resin applied in a later step does not penetrate. In addition, since the adhesive 107 after adhesion has a closed shape surrounding the outer periphery, it has a bank function that holds the curable resin applied in a later step in the observation region (opening) 11 until it hardens. As the adhesive 107, for example, an epoxy adhesive, a silicon adhesive, Superbond (registered trademark) (manufactured by Sun Medical Co., Ltd.), Ionosit-Baseliner (manufactured by DMG Co., Ltd.), LuxaFlow Star (manufactured by DMG Co., Ltd.), etc. can be used.

[0033] (Resin coating process) As shown in Fig. 4(c), a liquid 102A of a hardening resin is applied to one surface 101a of the first resin film. The application method is not particularly limited, but should be such that the liquid 102A does not start hardening during application. When the observation region 11 is wide, the second resin film 102 is formed thicker near the outer periphery due to the curved shape of the surface of the living body (brain) 10, so that it may be necessary to form a bank structure using an adhesive in the resin film adhesion step.

[0034] (Resin curing process) As shown in FIG. 4(d), the liquid 102A of the curable resin applied to the observation region 11 is cured under predetermined conditions. Here, an example will be described in which the liquid 102A is a photocurable resin. The liquid 102A is irradiated with predetermined light to cure the liquid 102A. The light to be irradiated is determined in consideration of the material of the photocurable resin. The preferred light irradiation time differs depending on the photocurable resin to be irradiated, but can be, for example, about 30 to 600 seconds. After the liquid 102A is cured, the optical member 100 of this embodiment manufactured in the observation region 11 is obtained.

[0035] As described above, the optical member 100 of the present embodiment is made of a material with a low refractive index close to the refractive index of the observation region of the living body 10, so that deterioration of light collection in the optical path between the living body 10 and the microscope is suppressed. Furthermore, since the optical member 100 uses the deformable first resin film 101 in the portion that directly contacts the living body 10, the portion of the first resin film 101 can be brought into close contact with the observation region 11 regardless of the surface shape of the observation region 11, and deterioration of light collection due to the formation of a gap can be suppressed. Furthermore, since the second resin film 102 is applied onto the first resin film 101 in a deformable liquid state and then solidified, it can be formed in a state of being in close contact with the first resin film 101 regardless of the surface shape of the first resin film 101. Therefore, by using the optical member 100, an observation window that is in close contact with the living body 10 can be realized, and high-resolution observation is possible.

[0036] Furthermore, when biological observation is performed using the optical member 100 of this embodiment, the optical member 100 can be tightly attached to biological tissue without any gaps, without contacting the biological tissue with the curable second resin film 102. Therefore, various curable resins can be applied regardless of their biocompatibility, greatly expanding the range of application.

[0037] Moreover, the optical element 100 is fixed to the observation region of the living body by the second resin film 102 adhered to the outer periphery 12 of the observation region 11. Therefore, the optical transparency of the optical element 100 is maintained, so that stable observation can be performed for a long period of time, and information such as the time change of each cell can be obtained.

[0038] In addition, the optical member 100 has the first resin film 101 having biocompatibility in the portion that comes into direct contact with the living body 10, so that it is possible to reduce damage to the living body 10, such as inflammation and bleeding, that occurs due to the contact. Therefore, it is possible to suppress deterioration of the light collection from the living body 10 and to observe the true state of the living body 10 without the influence of the observation. EXAMPLES

[0039] The effects of the present invention will be more clearly understood by the following examples. Note that the present invention is not limited to the following examples, and can be modified as appropriate without departing from the spirit and scope of the present invention.

[0040] Example 1 The observation area of ​​the brain of a living mouse was exposed, and the optical member of the above embodiment was fabricated therein. 2 The first resin film had a main surface area of ​​approximately 70 mm 2A PEO-PDMS-CYTOP sheet of the above was used. In this PEO-PDMS-CYTOP sheet, the thickness of the CYTOP portion was set to about 130 nm, and the thickness of the PDMS portion was set to about 7 nm. Ionosit-baseliner was used as an adhesive to bond the edge of the first resin film to the outer periphery of the observation area. NOA83H was used as the photocurable resin, and it was cured by irradiating UV light for about 150 seconds to form a second resin film with a refractive index of 1.56. The thickness of this second resin film was about 100 μm to 200 μm.

[0041] Figures 5(a) to (c) are photographs of the observation area of ​​the brain taken immediately after, 10 days after, and 20 days after the optical element was manufactured, respectively. In all photographs, the entire observation area is clearly visible through the optical element. It can be seen that the optical element, which has optical transparency, is formed over the entire observation area and is in contact with the brain surface without any gaps. Furthermore, since no change in clarity is observed over time, it can be seen that no displacement, peeling, damage, etc. has occurred.

[0042] Example 2 An optical member was manufactured in the same manner as in Example 1, except that NOA136 was used as the photocurable resin and cured by irradiating with UV light for about 200 seconds to form a second resin film having a refractive index of 1.36.

[0043] 6(a)-(c) are photographs of the observation area of ​​the brain taken immediately after, 1 week later, and 16 weeks later, respectively, after the optical member was manufactured. In each photograph, the entire observation area is clearly captured through the optical member, as in Example 1. Here again, it can be seen that the optical member having light transmission is formed over the entire observation area and is in contact with the surface of the brain without any gaps, and no positional shift, peeling, damage, or the like occurs over time. Compared to Example 1, the clarity of the captured observation area is increased. This is thought to be because the refractive index difference between the brain and the first resin film and the refractive index difference between the first resin film and the second resin film are both small, and the occurrence of spherical aberration and unnecessary reflection due to the refractive index difference is reduced in the optical path between the brain and the microscope.

[0044] (Examples 3 and 4) The inside of the structure produced by imitating the observation part of the living body was observed through a second resin film (thickness 150 μm) formed in the same manner as in Examples 1 and 2. FIG. 7 is a cross-sectional view showing the state in which the structure 200 is observed. The structure 200 used was composed of an agarose gel 201 with a refractive index of 1.33 and YG beads 202 dispersed in the gel 201, and contained in a container 203. The YG beads 202 correspond to fluorescent dye molecules dispersed in the living body. A resin film 204 was placed on the surface of the structure 200, water 205 was dropped on the resin film 204, and the water 205 was brought into contact with an objective lens 206 of a microscope, and the inside of the structure 200 was observed.

[0045] 8(a) and (b) are graphs comparing the full width at half maximum (FWHM) obtained from the spatial distribution of the fluorescent image obtained at depths of 200 μm, 500 μm, and 1000 μm in Example 3 using the second resin film 204 prepared in the same manner as in Example 1. The full width at half maximum in FIG. 8(a) is the full width at half maximum (lateral FWHM) obtained from the distribution of the spread in the direction perpendicular to the light propagation path. The full width at half maximum in FIG. 8(b) is the full width at half maximum (axial FWHM) obtained from the distribution of the spread in the depth direction. While no difference in the full width at half maximum is observed in the direction perpendicular to the light propagation path, in the depth direction, the full width at half maximum tends to become slightly larger the deeper the position is.

[0046] 9(a) and (b) are graphs comparing the full width at half maximum (FWHM) from the spatial distribution of the fluorescent image obtained at each depth position in Example 4 using the second resin film 204 prepared in the same manner as in Example 2, as in Example 3. The full width at half maximum in FIG. 9(a) is the full width at half maximum obtained from the distribution of the spread in the direction perpendicular to the light propagation path. The full width at half maximum in FIG. 9(b) is the full width at half maximum obtained from the distribution of the spread in the depth direction. While no difference in the full width at half maximum is observed in the direction perpendicular to the light propagation path, the full width at half maximum tends to be slightly larger in the depth direction. The tendency for the change in the full width at half maximum to be smaller in the depth direction compared to Example 3 is due to the lower refractive index of the second resin film.

[0047] Example 5 As in Example 1, an optical member was fabricated in the observation region of the mouse brain. However, the area of ​​the observation region was set to about 10 mm 2 It was decided.

[0048] Comparative Example 1 The second resin film alone was prepared in the observation area of ​​the mouse brain under the same conditions as in Example 5.

[0049] The inflammatory state of the brain in Example 5 was compared with that in Comparative Example 1 using an immunostaining method. Specifically, cell nuclei (Hoechst 33258), astrocytes (GFAP), and microglia (lba1) contained in the brain were separately displayed in Example 5 and Comparative Example 1 by immunostaining. Figures 10(a) and (d) are images in which only cell nuclei are displayed in Example 5 and Comparative Example 1, respectively. Figures 10(b) and (e) are images in which only astrocytes are displayed in Example 5 and Comparative Example 1, respectively. Figures 10(c) and (f) are images in which only microglia are displayed in Example 5 and Comparative Example 1, respectively. The observation area in which the optical member was manufactured is indicated by a dashed line.

[0050] Comparing Example 5 and Comparative Example 1, the images of cell nuclei that do not reflect the inflammatory state are similar, whereas the images of astrocytes and microglia are brighter near the observation area (below the dashed line) in Comparative Example 1 than in Example 5, indicating that greater inflammation has occurred. From this result, it can be seen that inflammation occurring in the brain is suppressed to a smaller extent when the second resin film is formed via the first resin film, compared to when the resin film is formed directly on the brain.

[0051] Example 6 As in Example 1, an optical member was produced in the observation region of the mouse brain, and the brain was observed using a two-photon microscope.

[0052] Figure 11 shows images of cerebral nerve cells visualized by this observation. Image A on the top is an image of nerve cells in the entire observation area (8mm x 6mm) where the optical components were installed. Image B on the bottom left is an enlarged image of a portion (0.5mm x 0.5mm) of image A, and image C on the bottom right is an even further enlarged image of a portion (0.15mm x 0.15mm) of image B.

[0053] At all magnifications, clear, high-resolution images were obtained. 2 ) is significantly larger than the area of ​​the observation region in conventional technology, but the influence of the curved shape of the brain is suppressed, and there is no deterioration in light collection due to bleeding from the surface of the living body, inflammation, etc. This is thought to be because the first resin film, which is flexible and biocompatible, comes into contact with the living body, allowing the optical members to be in contact with the living body without any gaps, without applying pressure to the surface, and reducing damage to the living body.

[0054] In high-magnification image C, the dendrites branching out in a complex manner from the nerve cells can be seen. The spine-like structures (spines) on the dendrites can also be seen. The reason that images with such high resolution can be obtained is thought to be that the difference in refractive index between the brain and the first resin film, and between the first and second resin films, are both small, reducing the occurrence of spherical aberration due to the difference in refractive index and unnecessary reflections in the optical path between the brain and the microscope.

[0055] Figure 12 is an image of a wide area including the cerebral cortex, midbrain, and cerebellum visualized by the same observation. The cerebral cortex, midbrain, and cerebellum are extremely difficult to observe because of their complex curved shapes, but it can be seen that by using the optical member of the present invention, clear images can be obtained and observation can be performed without problems. From this result, it can be seen that the optical member contacts the surface of the brain without any gaps, suppresses damage to the brain, and keeps the refractive index difference between the brain and the first resin film and the refractive index difference between the first resin film and the second resin film small. [Explanation of symbols]

[0056] 100 Optical components 101, 101A...First resin film 101a: One surface of the first resin film 101b... The other surface of the first resin film 101c End of first resin film 102...Second resin film 102a: Outer surface of second resin film 102A: Hardening resin liquid 103...Base 104...Structure section 105...PDMS membrane 106...chain PEO molecule 107...Adhesive 200...Structure 201...Gel 202···YG beads 203...container 204...Second resin film 205...Wednesday 206 Objective lens 10. Living body (brain) 10a: Biological surface 10A: Skull 11. Observation area 12...Outer periphery

Claims

1. An optical member that is placed on a surface of a living body and used to observe the inside of the living body, a first resin film having biocompatibility; a second resin film formed on one surface of the first resin film and having optical transparency; An optical member, characterized in that the difference in refractive index between the first resin film and the living body is 0.4 or less.

2. 2. The optical member according to claim 1, wherein the first resin film comprises a base portion having a refractive index difference of 0.4 or less with respect to the living body, and the biocompatible structure portion.

3. 3. The optical member according to claim 1, wherein the second resin film has a refractive index difference of 0.4 or less with respect to the living body.

4. 3. The optical member according to claim 1, wherein the living body is an animal brain, and the first resin film and the second resin film have refractive indices of 1.3 or more and 1.4 or less.

5. A method for producing the optical member according to claim 1 or 2 in an observation area on the surface of a living body, comprising the steps of: a resin film attaching step of attaching the first resin film to the observation area; a resin application step of applying a liquid curable resin to a surface of the first resin film opposite to the observation area; and a resin curing step of curing the applied curable resin.

6. The method for producing an optical member according to claim 5 , further comprising a resin film bonding step of bonding an end portion of the first resin film to an outer periphery of the observation region.

Images