Cell chip

Abstract

Provided is a cell chip excellent in cell drying resistance, cell retention, and detection of a chemical substance such as an odorant. The cell chip includes a compartment containing a cell and a gel

Description

Title of Invention: CELL CHIP Technical Field

[0001] The present invention relates to a cell chip and the like. Background Art

[0002] Groups of odorous substances associated with specific human diseases and mental states have been identified. Owing to their high value as diagnostic markers, there has been growing interest in developing various odor sensors that target these substances. Biological odorant receptors exhibit excellent characteristics, including diversity, sensitivity, and selectivity, which are not found in conventional odor sensor elements such as semiconductors; thus, these odorant receptors offer a promising foundation for the development of novel odor sensors using them as sensor elements.

[0003] PTL 1 discloses the use of cells expressing modified odorant receptors or lipid bilayer membranes incorporating modified odorant receptors as odor sensors. Citation List Patent Literature

[0004] PTL 1: WO2022 / 024902A Summary of Invention Technical Problem

[0005] Odor sensors that rely on the process of artificially preparing lipid bilayer membranes equipped with sensor proteins (e.g., odorant receptors) are often inefficient to produce, and there has been demand for further improvement in the production efficiency of odor sensors. The present inventors then focused on using cells that express sensor proteins.

[0006] From the perspective of convenience in use, the cells used as a chemical sensor such as an odor sensor are desirably those prepared in advance and retained in containers, which can be used when needed, rather than cells that are cultured and prepared each time for use. In the former case, it is necessary to keep the cells from drying out until they are used, and it is also important that the cells are stably maintained, considering factors such as transportation from the manufacturer to the place of use.

[0007] Furthermore, from the perspective of using the cells for disease diagnosis and other assessments, it is desirable to simultaneously use multiple types of cells expressing different odorant receptors. From this perspective, it is desirable to use the cells in the form of a cell chip.

[0008] Accordingly, an object of the present disclosure is to provide a cell chip excellent in cell desiccation resistance, cell retention, and detection of chemical substances, such as odorants. Solution to Problem

[0009] In the course of conducting research, the present inventors focused on the fact that a cell chip containing compartments each containing cells and a hydrogel can prevent cells from drying out and stably retain the cells. However, they found that the increase in response activity of sensor protein after the addition of a chemical substance is gradual in the presence of a hydrogel, interfering with quick and stable measurement of the activity. Based on this finding, the inventors discovered that a cell chip containing compartments each containing cells and a gel capable of converting into a sol could achieve the object and solve the problem described above. Specifically, the present disclosure encompasses the following embodiments.

[0010] Item 1. A cell chip comprising a compartment containing a cell and a gel capable of converting into a sol.

[0011] Item 2. The cell chip according to Item 1, wherein the gel is a gel capable of converting into a sol by temperature control, light irradiation, or addition of a chemical agent.

[0012] Item 3. The cell chip according to Item 2, wherein the gel is a gel capable of converting into a sol by temperature control.

[0013] Item 4. The cell chip according to Item 3, wherein the gel has a sol-formation temperature of 40°C or lower.

[0014] Item 5. The cell chip according to Item 3, wherein the gel has a sol-formation temperature of 30°C or lower.

[0015] Item 6. The cell chip according to Item 3, wherein the gel has a sol-gel transition temperature of 4 to 25°C.

[0016] Item 7. The cell chip according to Item 1, wherein the sol formed after solation of the gel has a viscosity of 20 mPa-s or less .

[0017] Item 8. The cell chip according to Item 1, wherein the gel has a storage elastic modulus at 4°C of 0.01 to 20 kPa.

[0018] Item 9. The cell chip according to any one of Items 1 to 8, for use in a method for detecting a test chemical substance, the method comprising, after solation of the gel, bringing the cell into contact with the test chemical substance.

[0019] Item 10. The cell chip according to any one of Items 1 to 8, for use in detecting light from the cell.

[0020] Item 11. The cell chip according to any one of Items 1 to 8, wherein the cell is an insect cell.

[0021] Item 12. The cell chip according to any one of Items 1 to 8, wherein the cell comprises an exogenous polynucleotide containing a coding sequence for a sensor protein.

[0022] Item 13. The cell chip according to Item 12, wherein the sensor protein is an odorant receptor protein.

[0023] Item 14. A kit for immobilizing a cell, comprising a component for forming a gel capable of converting into a sol.

[0024] Item 15. The kit according to Item 14, for immobilizing a cell on a cell chip.

[0025] Item 16. A method for producing a cell for transport, comprising immobilizing a cell with a gel capable of converting into a sol.

[0026] Item 17. A method for detecting light from a cell, comprising converting a gel into a sol, the gel immobilizing the cell and being capable of converting into a sol.

[0027] Item 18. A gel capable of converting into a sol, wherein the gel is capable of converting into a sol by temperature control, the gel has a sol-formation temperature of 40°C or lower, the gel has a sol-gel transition temperature of 4 to 25°C, the sol formed after solation of the gel has a viscosity of 20 mPa-s or less, and the gel has a storage elastic modulus at 4°C of 0.01 to 20 kPa.

[0028] Item 19. A sol for forming the gel of Item 18.

[0029] Item 20. The kit according to Item 14, comprising the gel of Item 18 and / or the sol of Item 19.

[0030] Item 21. The kit according to Item 20, for immobilizing a cell to a cell chip.

[0031] Item 22. The method according to Item 16, wherein the gel is the gel of Item 18.

[0032] Item 23. The method according to Item 17, wherein the gel is the gel of Item 18. Advantageous Effects of Invention

[0033] The present disclosure provides a cell chip excellent in cell desiccation resistance, cell retention, and detection of chemical substances, such as odorants. Additionally, the present disclosure also provides a kit for immobilizing cells to a cell chip, a method for producing cells for transport, a method for detecting light from cells, a gel suitable for use in the cell chip, a sol for forming such a gel, and so on. Brief Description of Drawings

[0034] Fig. 1 shows the results of measuring the activity of an odorant receptor in Test Example 4. The vertical axis indicates fluorescence intensity, and the horizontal axis indicates the passage of time. The arrow indicates the point at which compound a (a substance to which ORA cells respond) was added. Fig. 2 shows the results of measuring the activity of an odorant receptor in Test Example 5. The vertical axis indicates fluorescence intensity, and the horizontal axis indicates the passage of time. The arrow indicates the point at which compound a (a substance to which ORA cells respond) was added. Fig. 3 shows the results of measuring the activity of an odorant receptor in Test Example 6. The vertical axis indicates the value determined by subtracting the average background value (the average of the background values during the 20 seconds preceding the addition of the compound) from the maximum fluorescence intensity. On the horizontal axis, the percentage indicates the gelatin concentration, and "Without Gel" indicates the case in which a buffer solution was added instead of a gelatin solution. Fig. 4 shows the results of measuring the activity of an odorant receptor in Test Example 7. The vertical axis indicates the value determined by subtracting the average background value (the average of the background values during the 20 seconds preceding the addition of the compound) from the maximum fluorescence intensity. On the horizontal axis, "Without Gel" indicates the case in which a buffer solution was added instead of a gelatin solution, while the others indicate the presence or absence of sol after liquefaction of a hydrogel. Fig. 5 shows the results of measuring the viscosity of a sol in Test Example 8. The vertical axis indicates the measured viscosity values. The horizontal axis indicates the fish gelatin concentration in a gelatin solution. Fig. 6 shows the results of measuring the viscosity of a sol in Test Example 9. The vertical axis indicates the measured viscosity values. The horizontal axis indicates the fish gelatin concentration in a gelatin solution. Fig. 7 shows the results of measuring storage elastic modulus and sol-gel transition temperature in Test Example 10. Description of Embodiments

[0035] In the present specification, the terms "comprising," "containing," and "including" include the concepts of comprising, containing, consisting essentially of, and consisting of. In an embodiment, the present disclosure relates to a cell chip comprising a compartment containing a cell and a gel capable of converting into a sol ("the cell chip of the present disclosure" in the present specification). The following provides an explanation of the cell chip.

[0037] The cell is not particularly limited. From the perspective of chemical detection suitability, the cell is preferably animal cells, such as insect cells or mammalian cells, with insect cells being particularly preferred due to the ease of management, such as not requiring CO2 or temperature control.

[0038] The insect cells for use include, for example, Sf cells, MG1 cells, High Five™ cells, and BmN cells. Sf cells for use include, for example, Sf9 cells (ATCC CRL1711) and Sf21 cells. Insect cells, which possess coding sequences for insect odorant receptors in their genome, are usable as chemical sensors. Of the insect cells, those derived from insects of the family Arctiidae are particularly preferred.

[0039] The cells derived from insects of the family Arctiidae are not particularly limited as long as they are primary cultured cells or established cell lines of biological constituent cells derived from insects of the family Arctiidae.

[0040] Examples of the family Arctiidae include subfamilies such as Arctiinae, Lithosiinae, and Syntominae, among which the subfamily Arctiinae is preferred. The subfamily Arctiinae is, for example, preferably the genus Spilosoma, Spilarctia, or Rhagonis, with the genus Spilosoma being particularly preferable. While there is no particular limitation to the genus Spilosoma, Spilosoma imparilis is particularly preferable.

[0041] The cells derived from insects of the family Arctiidae can be obtained from known biological banks or collected and cultured from living insects of the family Arctiidae according to or with reference to known methods; if necessary, they can be established as cell lines.

[0042] Examples of cells derived from Spilosoma imparilis include FFPRI-Splm-2AM-SF cells (MAFF No.: 275052) and FFPRI-Splm-2AM-IPL411 cells (MAFF No.: 275053) from the Genebank Project, National Agriculture and Food Research Organization.

[0043] The cell preferably contains an exogenous polynucleotide containing a coding sequence for a sensor protein. This enables the expression of any sensor protein and enables increased expression levels of a target sensor protein, thereby enhancing the detection sensitivity for a target chemical substance.

[0044] The "exogenous polynucleotide" is not particularly limited as long as it refers to a polynucleotide containing a base sequence that is not derived from the genomic DNA (in particular, chromosomal genomic DNA) of an insect cell.

[0045] In the present specification, the polynucleotide includes not only typical polynucleotides such as DNA and RNA inherent in organisms, but also polynucleotides with known chemical modifications, artificial polynucleotides, and like polynucleotides, as listed below. To prevent degradation due to hydrolases such as nucleases, the phosphate residue of each nucleotide can be substituted with a chemically modified phosphate residue, such as phosphorothioate (PS), methylphosphonate, or phosphorodithionate. The hydroxyl group at position 2 of the ribose of each ribonucleotide may also be substituted with -OR (R indicates, for example, CH3 (2'-O-Me) , CH2CH2OCH3(2'-O-MOE) , CH2CH2NHC (NH)NH2, CH2CONHCH3, or CH2CH2CN) . Additionally, the nucleobase moiety (pyrimidine, purine) may be chemically modified, by, for example, introduction of a methyl group or a cationic functional group into position 5 of the pyrimidine base, or substitution of the carbonyl group at position 2 with thiocarbonyl. Additionally, the polynucleotide of the present invention also includes, but is not limited to, those formed by modifying the phosphate moiety or the hydroxyl moiety, for example, with biotin, an amino group, a lower alkyl amine group, or an acetyl group. The polynucleotide for use can also be, for example, BNA (LNA) , which is prepared by crosslinking the 2' oxygen and the 4' carbon in the ribose moiety of a nucleotide to fix the ribose moiety in N-conformation.

[0046] The sensor protein may be selected from proteins capable of detecting the presence of a chemical substance, such as a receptor protein that uses a chemical substance as a ligand. The sensor protein is particularly preferably an odorant receptor protein.

[0047] The insect odorant receptor protein is a membrane protein with a seven-transmembrane structure and functions as an odor sensor in the organisms. The odorant receptor protein is composed of the following components that are sequentially linked from the amino terminus ("N-terminus" below) to the carboxyl terminus ("C-terminus" below): N-terminal region (NT), first transmembrane domain (TM1) , first extracellular loop (ECI) , second transmembrane domain (TM2), first intracellular loop (IC1), third transmembrane domain (TM3), second extracellular loop (EC2), fourth transmembrane domain (TM4) , second intracellular loop (IC2), fifth transmembrane domain (TM5), third extracellular loop (EC3), sixth transmembrane domain (TM6), third intracellular loop (IC3), seventh transmembrane domain (TM7), and C-terminal region (CT). In the present disclosure, each region is determined by structural prediction using TMpred (K. Hofmann, W. Stoffel, TMbase - a database of membrane spanning proteins segments, Biol. Chern. Hoppe-Seyler, 374 (1993), p. 166, https: / 1embnet.vital-it. ch / softwareZTMPRED_form.html) (with default conditions).

[0048] The insect of origin for the insect odorant receptor protein is preferably an insect in the order Diptera, such as the family Culicidae and the family Drosophilidae; an insect in the order Lepidoptera, such as the family Bombycidae; an insect in the order Hymenoptera, such as the family Apidae; an insect in the order Orthoptera, such as the family Acrididae; and an insect in the order Hemiptera, such as the family Cimicidae, and more preferably an insect in the order Diptera, such as the family Culicidae and the family Drosophilidae; an insect in the order Orthoptera, such as the family Acrididae; and an insect in the order Hemiptera, such as the family Cimicidae. Examples of insects in the family Culicidae include Anopheles gambiae, Aedes aegypti, and Culex quinquefasciatus. Examples of insects in the family Drosophilidae include Drosophila melanogaster, Drosophila pseudoobscura, and Drosophila virilis. Examples of insects in the family Bombycidae include Bombyx mori, Bombyx mandarina, and Trilocha varians. Examples of insects in the family Apidae include Apis mellifera, Apis florea, Apis dorsata, and Bombus terrestris. Examples of insects in the family Acrididae include Locusta migratoria. Examples of insects in the family Cimicidae include Cimex lectularius.

[0049] Specifically, examples of wild-type insect odorant receptor proteins include the following: AaORl, AaOR2, AaOR4, AaOR5, AaOR6, AaOR8, AaOR9, AaORl0a, AaORl5, AaOR22, AaOR24, AaOR25, AaOR2 6, AaOR27, AaOR28, AaOR30, AaOR34, AaOR36, AaOR38, AaOR41a, AaOR41b, AaOR42, AaOR43, AaOR44, AaOR47, AaOR49, AaOR50, AaOR52, AaOR54, AaOR58, AaOR59, AaOR60, AaORSl, AaOR64, AaOR65, AaOR66, AaOR67a, AaOR69a, AaOR70, AaOR71, AaOR72a, AaOR73, AaOR74, AaOR75, AaOR77, AaOR78, AaOR79, AaOR81, AaOR83b, AaOR84, AaOR85, AaOR86, AaOR87, AaOR91, AaOR95, AaOR97, AaOR96, AaOR99, AaORlOO, AaOR102, AaOR103, AaOR104a, AaOR105, AaOR107, AaOR108, AaOR109, AaORllO, AaOR112, AaOR114, AaOR116, AaOR117, AaOR118, AaOR122, AaOR125, AaOR128, AgORl, AgOR2, AgOR3, AgOR4, AgOR5, AgOR6, AgOR8, AgOR9, AgORlO, AgORlla, AgOR12a, AgOR12b, AgOR13, AgORl4, AgORl5, AgORl6a, AgORl7, AgORl8, AgOR20, AgOR21, AgOR23, AgOR25, AgOR2 6, AgOR27, AgOR28, AgOR30, AgOR34, AgOR36, AgOR37, AgOR38, AgOR39a, AgOR40, AgOR42, AgOR44, AgOR45, AgOR4 6, AgOR47, AgOR49, AgOR50, AgOR54, AgOR56a, AgOR57, AgOR60, AgOR61, AgOR62, AgOR63, AgOR64, AgOR65, AgOR69, AgOR70, AgOR71, AgOR72, AgOR74, AgOR75, AgOR76a, AmORl, AmOR3, AmOR9, AmORl0, AmOR13, AmOR41, AmOR51, AmOR52, AmOR55, AmOR71, AmOR73, AmOR78, AmOR85, AmOR89, AmOR90, AmOR114, AmOR115, AmORllS, AmOR120, AmOR121, AmOR161, BmORl, BmOR2, BmOR3, BmOR4, BmOR5, BmOR8, BmOR9, BmORlO, BmOR13, BmORl7, BmORl8, BmOR23, BmOR24, BmOR25, BmOR35, BmOR36, BmOR42, BmOR45, BmOR49, BmOR51, BmOR52, BmOR55, BmOR56, BmOR61, DmORla, DmOR9a, DmOR19a, DmOR22a, DmOR22b, DmOR22c, DmOR24a, DmOR30a, DmOR33a, DmOR33b, DmOR33c, DmOR35a, DmOR42b, DmOR43a, DmOR45a, DmOR45b, DmOR47a, DmOR49b, DmOR59b, DmOR65b, DmOR65c, DmOR67b, DmOR67c, DmOR69a, DmOR71a, DmOR74a, DmOR82a, DmOR83a, DmOR83c, DmOR85a, DmOR85c, DmOR85e, DmOR85f, DmOR88a, DmOR92a, DmOR94a, DmOR94b, and DmOR98b. [ 0050] In the present specification, OR denotes "odorant receptor." Dm indicates derivation from Drosophila melanogaster, Bm indicates derivation from Bombyx mori, Ag indicates derivation from Anopheles gambiae, and Aa indicates derivation from Aedes aegypti. The amino acid sequences of various odorant receptor proteins, including these, and their coding sequences are either known or can be readily identified through sequence identity searches based on known sequences.

[0051] The sensor protein may contain one or more amino acid mutations in its wild-type amino acid sequence, provided that the chemical response activity is not significantly decreased. The phrase "not significantly decreased" means, for example, that the chemical response activity of a sensor protein containing amino acid mutations is, for example, at least 50%, preferably at least 60%, more preferably at least 70%, even more preferably at least 80%, and yet more preferably at least 90% of the chemical response activity of the wild-type sensor protein, taken as 100%.

[0052] The amino acid mutation is, for example, substitution, insertion, addition, or deletion of an amino acid, preferably substitution, and particularly preferably conservative substitution.

[0053] In the present specification, "conservative substitution" refers to the substitution of an amino acid residue with another amino acid residue having a similar side chain. For example, the substitution between amino acid residues having a basic side chain such as lysine, arginine, or histidine is considered to be a conservative substitution. The following substitutions between other amino acid residues are also considered to be a conservative substitution: the substitution between amino acid residues having an acidic side chain such as aspartic acid and glutamic acid; the substitution between amino acid residues having an uncharged polar side chain such as glycine, asparagine, glutamine, serine, threonine, tyrosine, or cysteine; the substitution between amino acid residues having a nonpolar side chain such as alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, or tryptophan; the substitution between amino acid residues having a p-branched side chain such as threonine, valine, or isoleucine; and the substitution between amino acid residues having an aromatic side chain such as tyrosine, phenylalanine, tryptophan, or histidine.

[0054] The sensor protein may contain its wild-type amino acid sequence or an amino acid sequence having, for example, at least 70%, preferably at least 80%, more preferably at least 90%, even more preferably at least 95%, still more preferably at least 98%, and particularly preferably at least 99% identity to the wild- type amino acid sequence.

[0055] In the present specification, the "identity" of amino acid sequences refers to the degree to which two or more contrastable amino acid sequences match each other. Thus, the higher the degree of match between two amino acid sequences, the higher the identity or similarity of those sequences. The level of amino acid sequence identity is determined, for example, by using FASTA, which is a tool for sequence analysis, with default parameters. Alternatively, the level of amino acid sequence identity can be determined by using the BIAST algorithm by Karlin and Altschul (Karlin S., Altschul S. F. Methods for assessing the statistical significance of molecular sequence features by using general scorings schemes, Proc. Natl. Acad. Sci. USA. 87: 2264-2268 (1990); Karlin S., Altschul S. F. Applications and statistics for multiple high-scoring segments in molecular sequences, Proc Natl Acad Sci USA. 90: 5873-7 (1993)). A program called "BLASTX," based on this BLAST algorithm, has been developed. The specific techniques of these analysis methods are known and can be found on the website of the National Center of Biotechnology Information (NCBI) (http: / / www.ncbi.nlm.nih.gov / ).

[0056] The sensor protein may contain other amino acid sequences, such as protein tags, fluorescent proteins, luminescent proteins, signal sequences, or other proteins or peptides, attached thereto, provided that the chemical response activity is not significantly impaired. Examples of protein tags include biotin, His tag, FLAG tag, Halo tag, MBP tag, HA tag, Myc tag, V5 tag, and PA tag.

[0057] In the present specification, "chemical response activity" refers to the property of a sensor protein to recognize a chemical substance and initiate signal transduction activity (e.g., ion channel activity) either alone or in conjunction with other proteins. In the case of odorant receptors, "chemical response activity" refers to the property of an odorant receptor to recognize a chemical substance and form an odorant receptor complex, together with an olfactory receptor co-receptor, thereby exhibiting ion channel activity upon activation. The chemical response activity of a sensor protein can be measured by using the signal transduction activity of the sensor protein in contact with a chemical substance as an indicator (e.g., by quantifying and evaluating the amount of signal molecules). In the case of odorant receptors, their chemical response activity can be measured using the ion channel activity of an odorant receptor complex formed of an odorant receptor in contact with a chemical substance and an olfactory receptor co-receptor as an indicator. For example, a chemical substance is brought into contact with cells that express a protein that becomes fluorescent or luminescent in response to the influx of ions (e.g., calcium ions) into the cells when (a) an odorant receptor, (b) an olfactory receptor co-receptor, and (c) an odorant receptor complex respond, and then the amount of luminescence of the cells is measured. The greater the measured amount of luminescence, the higher the response activity of the odorant receptor to the chemical substance is determined to be. Specifically, the chemical response activity can be measured according to the method described in PTL 1.

[0058] The coding sequence for the sensor protein is not particularly limited as long as it is a base sequence encoding the sensor protein. In an embodiment, the exogenous polynucleotide contains an expression cassette for a sensor protein. The expression cassette is not particularly limited as long as it is a polynucleotide capable of expressing the sensor protein within a cell. A typical example of expression cassettes for a sensor protein is a polynucleotide containing a promoter and the coding sequence for the sensor protein placed under control of the promoter.

[0059] The promoter is not particularly limited and can be selected as appropriate. The promoter for use can be selected from various types of pol II promoters, for example. Examples of pol II promoters include, but are not particularly limited to, CMV promoter, EFl promoter, SV40 promoter, MSCV promoter, and promoters derived from insect genes.

[0060] When the sensor protein is an insect odorant receptor, it is preferred that the exogenous polynucleotide contain a coding sequence for an insect olfactory receptor co-receptor. The insect olfactory receptor co-receptor is a membrane protein with a seven-transmembrane structure as with the odorant receptor and functions by forming a hetero-complex with an odorant receptor. The odorant receptor complex, which is a hetero-complex composed of an odorant receptor and an olfactory receptor co-receptor, has ion channel activity that is activated by odorant substances. When activated, the odorant receptor complex allows the influx of cations such as sodium ions (Na+) and calcium ions (Ca2+) into cells .

[0061] It is preferred that the exogenous polynucleotide include a coding sequence for a protein that becomes fluorescent or luminescent in response to the influx of ions (e.g., calcium ions) into the cell when the sensor protein (in particular, the odorant receptor protein) responds. Examples of such proteins include aequorin, Yellow Cameleon (YC), and GCaMP. Alternatively, the cell of the present disclosure preferably contains an iondependent fluorescent dye, such as calcium ion-dependent fluorescent dyes (e.g., Fura-2, Fluo-3, and Fluo-4).

[0062] The exogenous polynucleotide preferably contains a coding sequence for a drug-resistant gene to allow for drug screening of cells. For the drug-resistant gene, a gene resistant to a drug that can be used for drug screening of cells may be selected. Examples of drug-resistant genes include chloramphenicol resistance gene, tetracycline resistance gene, neomycin resistance gene, erythromycin resistance gene, spectinomycin resistance gene, kanamycin resistance gene, hygromycin resistance gene, and puromycin resistance gene.

[0063] It is preferred that the exogenous polynucleotide contains coding sequences such as a coding sequence for an insect olfactory receptor co-receptor, a coding sequence for a chromogenic or luminescent protein, and a coding sequence for a drug-resistant gene in the form of an expression cassette. The structure of the expression cassette is similar to that of the expression cassette for the sensor protein. The promoter of the expression cassette can be shared among multiple coding sequences.

[0064] The exogenous polynucleotide is preferably integrated into the genomic DNA (particularly preferably chromosomal genomic DNA) . This enables stable expression of the sensor protein, making it suitable for chemical detection. In this case, the polynucleotide can be a single continuous region within the genomic DNA or a combination of two or more continuous regions (e.g., a form in which the sensor protein-coding sequence is included in continuous region A, and the coding sequence for a drug-resistant gene is included in continuous region B, which is separate from continuous region A, or a form in which the sensor protein-coding sequence is included in both continuous region A and continuous region B).

[0065] In another embodiment, the polynucleotide may be in a state in which it is not integrated into the genomic DNA. In this case, the exogenous polynucleotide can be in the form of a vector, for example. In this case, the polynucleotide can be a single polynucleotide molecule, or two or more polynucleotide molecules (e.g., a form in which the sensor protein-coding sequence is included in polynucleotide molecule A, while the coding sequence for a drug-resistant gene is included in polynucleotide molecule B, which is a separate molecule from polynucleotide molecule A, or a form in which the sensor proteincoding sequence is included in both polynucleotide molecule A and polynucleotide molecule B).

[0066] The gel is not particularly limited as long as it can convert into a sol. It appears that solation ensures the high diffusivity of a target substance to be detected, enabling rapid and stable measurement. Additionally, solation simplifies the removal of the gel, thus enabling its replacement with a solution having superior diffusivity of the target substance to be detected. Therefore, in an embodiment, the present disclosure relates to a kit for immobilizing a cell on a cell chip, comprising a component for forming a gel capable of converting into a sol.

[0067] Examples of gels include gels that can convert into a sol by temperature control, light irradiation, or addition of a chemical agent. Of these, from the viewpoint of ease of preparation of gel components, simplicity of solation, and reversibility of sol-gel transition, gels that can convert into a sol by temperature control are preferred, and gels that can convert into a sol by temperature increase are more preferred.

[0068] From the perspective of achieving contact with the cell in the cell chip of the present disclosure to more firmly immobilize the cell while limiting thermal damage to the cell during sol formation, the sol-formation temperature of the gel capable of converting into a sol by temperature control is preferably 40°C or lower, more preferably 35°C or lower, even more preferably 30°C or lower, and particularly preferably 28°C or lower. From the perspective of stable maintenance of the gel at a temperature desirable for cell preservation, the lower limit of such a temperature is preferably 10°C, 15°C, 20°C, or 25°C. The "sol-formation temperature" can be defined as the temperature at which the loss tangent exceeds 1 when the gel is heated at a rate of +l°C / min in the dynamic viscoelasticity measurement in Test Example 10, described below.

[0070] The sol-gel transition temperature (i.e., the temperature at which a sol before gel formation transitions to a gel) of the gel capable of converting into a sol by temperature control is preferably 35°C or lower, more preferably 30°C or lower, even more preferably 25°C or lower, and particularly preferably 20°C or lower, from the perspective of achieving contact with the cell in the cell chip of the present disclosure to more firmly immobilize the cell while limiting thermal damage to the cell during sol preparation and gel formation. The lower limit of the temperature is not particularly limited as long as it is 0°C or higher; however, from the viewpoint of enabling stable gel formation in a temperature range in which cells do not freeze, the lower limit of the temperature is preferably 4°C or higher, and from the viewpoint of maintaining the gelled state regardless of temperature rise during transport, the lower limit of the temperature is more preferably 10°C or higher.

[0071] The sol-gel transition temperature can be measured according to the method in Test Example 10, described below.

[0072] The gel capable of converting into a sol preferably forms a sol with a viscosity of 20 mPa-s or less after solation. From the viewpoint of further improving the diffusivity of the target substance to be detected and making contribution to faster and more stable measurement, as well as improving workability during cell seeding, the viscosity is preferably 15 mPa-s or less, more preferably 10 mPa-s or less, even more preferably 8 mPa-s or less, still more preferably 6 mPa-s or less, and particularly preferably 5 mPa-s or less. The lower limit of the viscosity is not particularly limited, and can be, for example, 0 mPa-s, 0.1 mPa-s, 0.2 mPa-s, 0.5 mPa-s, or 1 mPa-s.

[0073] The viscosity can be measured according to or with reference to the method described in Test Example 8 or Test Example 9. The value measured by either method can be used as the viscosity. Preferably, the viscosity is a value measured according to or with reference to the method described in Test Example 9 (i.e., the viscosity after the sol is left to stand for 2 days at a sol formation temperature). A relatively lower viscosity indicates that the time-dependent increase in viscosity after sol formation is suppressed, demonstrating excellent handling properties.

[0074] The storage elastic modulus at 4°C of the gel capable of converting into a sol is not particularly limited, and is, for example, 0.001 to 100 kPa. From the viewpoint of retaining cells while limiting external forces on cells in contact with the gel (i.e., limiting damage to cells), the gel preferably has a storage elastic modulus at 4°C of 0.01 to 20 kPa, more preferably 0.02 to 10 kPa, even more preferably 0.05 to 5 kPa, and still more preferably 0.07 to 2 kPa.

[0075] The storage elastic modulus can be measured according to the method in Test Example 10, described below.

[0076] The component that forms a gel capable of converting into a sol (gel-forming component: a component cross-linked to form a network) is not particularly limited; examples include gelatin, polysaccharides, such as agar, carrageenan, starch, and xanthan gum, and water-soluble synthetic polymers, such as PVA and PEG. Of these, from the viewpoint of ease of developing desirable properties, a particularly preferable component is gelatin. Gelatin is obtained by pretreating raw collagen materials, such as cattle bones, cattle skin, pig bones, pig skin, and fish scales, with an acid or alkali, followed by washing with water, hot-water extraction, purification, and concentration for drying. The sol properties and gel properties of gelatin vary depending on the type of raw collagen material, pretreatment, hot-water extraction conditions, and other factors. In order to achieve the sol temperature, sol-gel transition temperature, sol viscosity, and gel elastic modulus suitable for the present invention described above, fish-derived gelatin (fish gelatin), among various kinds of gelatin, is particularly preferable; the sol properties and gel properties suitable for the present invention can be achieved by appropriately adjusting the pretreatment and hot-water extraction conditions.

[0077] The gel-forming component can be a single type or a combination of two or more types.

[0078] In an embodiment of the present disclosure, the content of gelatin in the gel capable of converting into a sol is preferably 50 mass! or more, more preferably 70 mass! or more, still more preferably 80 mass! or more, even more preferably 85 mass% or more, particularly preferably 90 mass% or more, and especially preferably 95 mass% or more (in particular, 100 mass%) based on 100 mass% of the gel-forming component.

[0079] In an embodiment of the present disclosure, the content of gelatin in the gel capable of converting into a sol is preferably 50 mass% or more, more preferably 70 mass% or more, still more preferably 80 mass% or more, even more preferably 85 mass! or more, particularly preferably 90 mass! or more, and especially preferably 95 mass% or more (in particular, 100 mass!) based on 100 mass! of the solid content that constitutes the gel.

[0080] When the gel capable of converting into a sol contains gelatin, the concentration of gelatin in the gel is preferably 0.5 to 10 mass!, more preferably 0.7 to 8 mass%, even more preferably 0.8 to 6 mass%, still more preferably 0.9 to 4 mass!, and particularly preferably 1 to 3.5 mass%, from the viewpoint of ease of developing desirable properties.

[0081] The solvent for the gel capable of converting into a sol is not particularly limited as long as it does not adversely affect cell viability to a significant degree. It is preferred that the solvent contains water. The water content in the solvent is preferably 50 mass! or more, more preferably 70 mass! or more, still more preferably 80 mass! or more, even more preferably 85 mass% or more, particularly preferably 90 mass! or more, and especially preferably 95 mass% or more (in particular, 100 mass!).

[0082] In an embodiment, the present disclosure relates to a gel capable of converting into a sol and a sol for forming the gel. More specifically, the gel is capable of converting into a sol by temperature control and satisfies one or more (preferably two, more preferably three, and particularly preferably five) requirements selected from the group consisting of the following: (a) the gel has a sol-formation temperature within a predetermined range, (b) the gel has a sol-gel transition temperature within a predetermined range, (c) the sol formed after solation of the gel has a viscosity within a predetermined range, (d) the gel has a storage elastic modulus at 4 °C within a predetermined range, and (e) the sol formed after gelation at 4°C and then resolation by heating to 25°C has a viscosity within a predetermined range.

[0083] The compartments of the cell chip of the present disclosure preferably each contain cells a gel capable of converting into a sol. The configuration of the compartments is not particularly limited as long as it is capable of retaining cells and a gel. From the perspectives of cell desiccation resistance, cell retention, production efficiency, or chemical detection, the compartments are preferably in the form of wells.

[0085] The material of the compartments is not particularly limited as long as the material can retain cells and a gel. The material can be, for example, resin or metal.

[0086] The arrangement of the cells and gel in the compartment is not particularly limited as long as the cell desiccation resistance and cell retention are ensured. For example, the cells are encapsulated in the gel in each compartment. The embodiment of encapsulation is not particularly limited as long as it is an embodiment in which at least some of the cells are shielded from the air outside the cell chip by the gel.

[0087] From the perspective of detection sensitivity, each compartment typically contains multiple cells. The number of cells per unit area (cm2) in a compartment is, for example, 5000 to 2000000 cells / cm2. From the perspective of detection sensitivity and cell viability, the number of cells per unit area is preferably 10000 to 1500000 cells / cm2, more preferably 10000 to 1000000 cells / cm2, even more preferably 20000 to 1000000 cells / cm2, still more preferably 50000 to 700000 cells / cm2, and particularly preferably 100000 to 500000 cells / cm2.

[0088] From the perspective of detection sensitivity or production efficiency, the bottom surface area of a single compartment is preferably 0.5 to 100 mm2, more preferably 1 to 30 mm2, and even more preferably 1.5 to 15 mm2. In an embodiment of the present invention, the upper limit of the area can be set to 80 mm2, 60 mm2, or 40 mm2. From the perspective of detection sensitivity or production efficiency, the number of compartments included in the cell chip is preferably 10 to 2000, more preferably 30 to 1000, and even more preferably 50 to 500.

[0090] It is preferred that the cell chip of the present disclosure include two or more (more preferably three or more, even more preferably four or more, still more preferably five or more, ten or more, 15 or more, or 20 or more) types of cells that differ from each other in the type of sensor protein.

[0091] The cell chip of the present disclosure can be produced by gelling a sol for forming the sol-formable gel in a compartment containing the sol and cells. The sol can be obtained according to or with reference to a known method. When gelatin is used as the gel-forming component, it is preferable to perform the following procedure from the viewpoint of ease of obtaining a gel / sol with the desirable properties described above: add powdered gelatin to a solvent, stir the mixture at 12 to 30°C (preferably 15 to 25°C) for 10 to 60 minutes (preferably 20 to 40 minutes), then heat the mixture to the dissolution temperature of the gelatin (e.g., 30 to 60°C), and stir the solution until complete dissolution.

[0092] The cell chip of the present disclosure can be used in detecting chemical substances (in particular, odorous substances). The chemical substances can be, for example, those in a sample such as body fluids (e.g., urine, blood, and saliva), air (e.g., indoor air and air inside packaging), and water (e.g., river water, seawater, tap water, clean water, and sewage). In this case, for example, the sample is added to compartments of the cell chip of the present disclosure; this allows the chemical substance in the sample to reach the cells and come into contact with the sensor protein in the cells. For example, a chemical substance can be detected by detecting ions flowing into a cell (e.g., by detecting a protein that becomes colored or luminescent in response to ions).

[0093] As described above, the cell chip of the present disclosure enables rapid and stable measurement by converting a gel into a sol. Thus, the cell chip of the present disclosure can be used in a method for detecting a test chemical substance, which includes, after solation of the gel, bringing the cells into contact with the test chemical substance. After solation, the test chemical substance may be brought into contact with the cells in the presence of the sol; alternatively, the sol may be removed, and another liquid may optionally be added to the compartments, and then the test chemical substance may be brought into contact with the cells. In the detection of luminescence from the cells (luminescence due to the addition of a substrate such as coelenterazine), the problem of being unable to perform rapid and stable measurements is more prominent. Thus, the technique of the present invention can be more suitably used. In this case, the problem can be more effectively resolved by removing the sol after solation.

[0094] The kit for immobilizing a cell of the present disclosure includes a gel component that can convert into a sol, a reagent, and / or an instrument (e.g., cell culture vessel) used in immobilizing cells with a gel. The gel component that can convert into a sol included in the kit may be in a powder form, gel form, or sol form. The cell culture vessel included in the kit has compartments for immobilizing cells. The bottom area of a single compartment is not particularly limited. From the viewpoint of detection sensitivity or production efficiency, the bottom area is preferably 0.5 to 100 mm2, more preferably 1 to 30 mm2, and even more preferably 1.5 to 15 mm2. In an embodiment of the present invention, the upper limit of the area may be set to 80 mm2, 60 mm2, or 40 mm2. As described above, cells for transport that can be stably transported can be produced by including the step of immobilizing cells with a gel capable of converting into a sol. After transport, the gel immobilizing the transportable cells can be converted into a sol and removed in use. This enables the use of cells in the absence of a gel or sol after stable transport, allowing for effective detection of light from cells, which can be problematic when the gel or sol is highly turbid, for example. Therefore, in an embodiment, the present disclosure relates to a method for producing a cell for transport, comprising immobilizing a cell with a gel capable of converting into a sol. Additionally, in an embodiment, the present disclosure relates to a method for detecting light from a cell, comprising converting a gel into a sol, the gel immobilizing the cell and being capable of converting into the sol. In the method for detecting light, after solation, a treatment to make cells emit light (e.g., addition of a substance or light irradiation) can optionally be performed. Examples

[0096] The present invention will be described in detail below with reference to Examples. However, the present invention is not limited to these Examples.

[0097] Test Example 1: Preparation of Stably Expressing Cell Cells derived from Spilosoma imparilis (Splm cells) were transfected with a transposon vector containing the coding sequence for an odorant receptor protein (ORA) , the coding sequence for an olfactory receptor co-receptor, the coding sequence for a calcium sensor fluorescence protein, and the coding sequence for a puromycin resistance gene that were all placed under control of a promoter sequence and that were positioned between the 5' ITR (inverted terminal repeat) and 3' ITR. Selection was performed with puromycin, thereby preparing Splm cells stably expressing odorant receptors in which the foreign DNA containing the above coding sequences and promoter sequence was integrated into the chromosomal genomic DNA ("ORA cells" below). The odorant receptor is an insect-derived odorant receptor and is a receptor for compound a. The ORA cells emit fluorescence in response to compound a.

[0098] Test Example 2, Preparation of Gelatin Solution Powdered fish gelatin (Fish Gelatin (Type A) manufactured by Nitta Gelatin Inc.) was added to an PBS solution, and the mixture was stirred at 17°C for 30 minutes, followed by heating the mixture to 35°C and stirring until complete dissolution, thereby obtaining a gelatin solution with a predetermined fish gelatin concentration. The solution was sterilized using a 0.22 pm filter or by autoclaving before being used in the following tests.

[0099] Test Example 3: Preparation of Acrylic Resin Solution 2-[[2-(Methacryloyloxy)ethyl]dimethylammonio]acetate (monomer: MO3N6O) and N,N'-[oxybis(2,l-ethanediyloxy-3,1-propanediyl)]bisacrylamide (crosslinking agent: 2AAmLN) were dissolved in an aqueous PBS (Nissui Pharmaceutical Co., Ltd. #05913) solution to prepare an aqueous MO3N6O / 2AAmLN solution. Lithium phenyl(2,4,6-trimethylbenzoyl)phosphinate (photopolymerization initiator: LPA) was dissolved in an aqueous PBS solution to prepare an aqueous LPA solution. The two aqueous solutions above were mixed and stirred so that the final concentration of MO3N6O was 0.8 mass%, the final concentration of 2AAmLN was 5.2 mass%, and the final concentration of LPA was 0.02 mass%, thereby obtaining an acrylic resin solution.

[0100] Test Example 4. Measurement of Odorant Receptor Activity 1 ORA cells were seeded in a Corning 3903 96-well plate at 5 x 104 cells / 100 pL / well and left to stand in a 27°C incubator (without CO2 supply) . Sf-900 III SFM medium was used for the culture medium. The following operations were performed after 24 hours from seeding. Test group 1: The culture fluid was removed from each well of the 96-well plate, and 40 pL of the acrylic resin solution was added to each well. The cells were irradiated with light of a wavelength of 365 nm at 110 mW / cm2 for 30 seconds using a UV irradiation device (LED light source, 365 nm, manufactured by CCS Inc.) to form a hydrogel. 210 pL of culture medium was added on top of the hydrogel, further followed by washing twice with culture medium Test group 2: Culturing was continued without forming a gel.

[0101] After 24 hours from the above operations, the medium was all removed, and 40 pL of 0.1% BSA / 1* Hanks' buffer / 20 mM HEPES buffer was added to each well in test group 1, while 80 pL of the same buffer was added to each well in test group 2. Compound a (a substance to which ORA cells respond) was added to each well so as to achieve a final concentration of 100 pM, and the changes in fluorescence intensity before and after the addition of compound a were quantified using a microplate reader (FlexStation 3, Molecular Devices).

[0102] Fig. 1 shows the results. In the absence of a hydrogel (test group 2), the fluorescence intensity after the addition of compound a rose sharply, and the fluorescence intensity was measured rapidly and stably. On the other hand, in the presence of a hydrogel (test group 1), the increase in fluorescence intensity after the addition of compound a was gradual, and rapid and stable measurement of fluorescence intensity could not be performed.

[0103] ORA cells were seeded in a Corning 3903 96-well plate at 5 x 104 / 100 pL / well and left to stand in a 27°C incubator (without CO2 supply) . Sf-900 III SFM medium was used as the culture medium. The following operations were performed after 24 hours from seeding. Test group A: The culture fluid was removed from each well of the 96-well plate, and 40 pL of a gelatin solution (sol with a fish gelatin concentration of 5 mass%) at 25°C was added to each well. A gel was allowed to form by letting it stand at 4°C for 3 hours. Test group B: Same as test group A. Test group C: Culturing was continued without forming a gel.

[0104] After the above operations, test groups A and B were allow to stand at 27°C for 1 hour to convert the gels into sols. In test group A, 40 pL of 0.1% BSA / lx Hanks' buffer / 20 mM HEPES buffer was added to each well without removing the sol. In test groups B and C, the sol or culture medium was removed, and then 80 pL of 0.1% BSA / lx Hanks' buffer / 20 mM HEPES buffer was added to each well. Compound a (a substance to which ORA cells respond) was added to each well so as to achieve a final concentration of 100 pM, and the changes in fluorescence intensity before and after the addition of compound a were quantified using a microplate reader (FlexStation 3, Molecular Devices).

[0105] Fig. 2 shows the results. In the case in which the gel was converted into a sol (test group A), the fluorescence intensity after the addition of compound a rose sharply, allowing for rapid and stable measurement of fluorescence intensity. In comparison of test group A with test groups B and C, immobilizing cells with a gel was found to have little effect on the speed and stability of chemical detection.

[0106] ORA cells were seeded in a Corning 3903 96-well plate at 5 x 104 cells / 100 pL / well and left to stand in a 27°C incubator (without CO2 supply) . Sf-900 III SFM medium was used for the culture medium.

[0107] After 24 hours from seeding, the culture fluid was removed from each well of the 96-well plate, and 40 pL of a gelatin solution at 25°C (sol with a fish gelatin concentration of 2 to 8 massh was added to each well. A gel was allowed to form by letting it stand at 4°C for at least 1 hour. 100 pL of culture medium was added on top of the gel. Additionally, another group was also prepared in which culturing was continued with 100 pL of culture medium without replacing the medium with the gelatin solution. After the gel formation operation, the samples were stored at 4°C.

[0108] After 72 hours from the gel formation operation, the gel was left to stand at 27°C for 1 hour to convert it into a sol. After the sol was removed, 80 pL of 0.1% BSA / lx Hanks' buffer / 20 mM HEPES buffer was added to each well. Compound a (a substance to which ORA cells respond) was then added to each well to achieve final concentrations of 0, 0.1, 1, and 10 pM, and the changes in fluorescence intensity before and after the addition of compound a were quantified using a microplate reader (FlexStation 3, Molecular Devices).

[0109] Fig. 3 shows the results. The chemical substance was detected in all cases in which the gel was used at different concentrations. The chemical substance was also detected even when the cells were immobilized with a hydrogel and stored at 4°C.

[0110] Test Example 7: Measurement of Odorant Receptor Activity 4 ORA cells were seeded in a Corning 3903 96-well plate at 5 x 104 cells / lOOpL / well and left to stand in a 27°C incubator (without CO2 supply) . Sf-900 III SFM medium was used for the culture medium.

[0111] After 24 hours from seeding, the culture fluid was removed from each well of the 96-well plate, and 40 pL of a gelatin solution (sol with a fish gelatin concentration of 5 mass!) at 25°C was added to each well. A gel was allowed to form by letting it stand at 4°C for 3 hours. Additionally, another group was also prepared in which culturing was continued with 100 pL of culture medium without replacing the medium with the gelatin solution.

[0112] After the gel formation operation, the gel was immediately left to stand at 27°C for 1 hour to convert it into a sol. After the sol was removed, 80 pL of 0.1% BSA / lx Hanks' buffer / 20 mH HEPES buffer was added to each well. Alternatively, after solation, 40 pL of 0.1% BSA / lx Hanks' buffer / 20 mM HEPES buffer was added without removing the sol. Compound a (a substance to which ORA cells respond) was added to each well to achieve final concentrations of 0, 0.1, 1, and 10 pM, and the changes in fluorescence intensity before and after the addition of compound a were quantified using a microplate reader (FlexStation 3, Molecular Devices).

[0113] Fig. 4 shows the results. The chemical substance was detected regardless of whether the sol removal operation was performed. However, the detection sensitivity was higher when the sol was removed.

[0114] Test Example 8: Sol Viscosity Measurement 1 A gelatin solution (sol with a fish gelatin concentration of 2 to 5 mass%) was added to a sample tube and left to stand for 1 hour in a column oven at 40°C for the purpose of eliminating thermal history. The sample tube was transferred to an incubator at 25°C and left to stand for 30 minutes. The sample tube was stored in a refrigerator at 4°C for one day to allow gelation. The sample tube was then transferred to an incubator at 25°C and left to stand for 1 hour to allow solation. The viscosity was measured using an EMS-1000 viscometer manufactured by Kyoto Electronics Manufacturing Co., Ltd., with a 2 mm aluminum probe at a measurement temperature of 25°C.

[0115] Fig. 5 shows the results. The gel formed from the gelatin solution (sol with a fish gelatin concentration of 2 to 5%) formed a sol with relatively low viscosity after solation.

[0116] Test Example 9: Sol Viscosity Measurement 2 A gelatin solution (sol with a fish gelatin concentration of 2 to 5 massd was added to a sample tube and left to stand for 1 hour in a column oven at 40°C for the purpose of eliminating thermal history. The sample tube was transferred to an incubator at 25°C and left to stand for 30 minutes. The sample tube was stored in a refrigerator at 4°C for one day to allow gelation. The sample tube was then transferred to an incubator at 25°C and left to stand for 2 days to allow solation. The viscosity was measured using an EMS-1000 viscometer manufactured by Kyoto Electronics Manufacturing Co., Ltd., with a 2 mm aluminum probe at a measurement temperature of 25°C.

[0117] Fig. 6 shows the results. A comparison between Fig. 5, which shows the measurement results one hour after solation, and Fig. 6, which shows the measurement results two days after solation, indicates that the viscosity of the sol at relatively high concentrations increases over time after solation.

[0118] Test Example 10: Measurement of Storage Elastic Modulus of Gel and Sol-Gel Transition Temperature Measurements were conducted using an MCR302 viscoelasticity meter manufactured by Anton Paar Japan K.K., with a CP50-1 plate with a sample volume of 1 ml, a frequency of 1 Hz, and a strain of 1%. Initially, viscosity measurements were performed at 25°C, followed by temperature sweep measurements by cooling to 4°C at a rate of -l°C / min. The sol-gel transition point was defined as the point at which the loss tangent falls 5 below 1. Subsequently, the storage elastic modulus was measured 10 minutes after the temperature reached 4°C.

[0119] Fig. 7 and Table 1 show the results. The storage elastic modulus at 4°C was 1.3 kPa for 5 wt%, 1.1 kPa for 4 wt%, 10 0.3 kPa for 3 wt%, 0.1 kPa for 2 wt%, and 0.002 kPa for 1 wt%.

[0120] Table 1 Gelatin Concentration (wt%) Sol-gel Transition Temperature (°C) 10 17 5 13 4 12 3 9 2 5 15

Claims

1. A cell chip comprisinga compartment containing a cell and a gel capable of converting into a sol.

2. The cell chip according to claim 1, wherein the gel is a gel capable of converting into a sol by temperature control, light irradiation, or addition of a chemical agent.

3. The cell chip according to claim 2, wherein the gel is a gel capable of converting into a sol by temperature control.

4. The cell chip according to claim 3, wherein the gel has a sol-formation temperature of 40°C or lower.

5. The cell chip according to claim 3, wherein the gel has a sol-formation temperature of 30°C or lower.

6. The cell chip according to claim 3, wherein the gel has a sol-gel transition temperature of 4 to 25°C.

7. The cell chip according to claim 1, wherein the sol formed after solation of the gel has a viscosity of 20 mPa-s or less .

8. The cell chip according to claim 1, wherein the gel hasa storage elastic modulus at 4°C of 0.01 to 20 kPa.

9. The cell chip according to any one of claims 1 to 8, for use in a method for detecting a test chemical substance, the method comprising, after solation of the gel, bringing the cell into contact with the test chemical substance.

10. The cell chip according to any one of claims 1 to 8, for use in detecting light from the cell.

11. The cell chip according to any one of claims 1 to 8, wherein the cell is an insect cell.

12. The cell chip according to any one of claims 1 to 8, wherein the cell comprises an exogenous polynucleotide containing a coding sequence for a sensor protein.

13. The cell chip according to claim 12, wherein the sensor protein is an odorant receptor protein.

14. A kit for immobilizing a cell, comprising a component for forming a gel capable of converting into a sol.

15. The kit according to claim 14, for immobilizing a cell on a cell chip.

16. A method for producing a cell for transport, comprising immobilizing a cell with a gel capable of converting into a sol.

17. A method for detecting light from a cell, comprising converting a gel into a sol, the gel immobilizing the cell and being capable of converting into a sol.

18. A gel capable of converting into a sol, whereinthe gel is capable of converting into a sol by temperature control,the gel has a sol-formation temperature of 40°C or lower,the gel has a sol-gel transition temperature of 4 to 25°C,the sol formed after solation of the gel has a viscosity of 20 mPa-s or less, andthe gel has a storage elastic modulus at 4°C of 0.01 to 20 kPa.

19. A sol for forming the gel of claim 18.

20. The kit according to claim 14, comprising the gel of claim 18 and / or the sol of claim 19.

21. The kit according to claim 20, for immobilizing a cell to a cell chip.

22. The method according to claim 16, wherein the gel is the gel of claim 18.

23. The method according to claim 17, wherein the gel is the gel of claim 18.INTERNATIONAL SEARCH REPORT International application No. PCT / J1’2024 / 017601 A. CLASSIFICATION OF SUBJECT MATTER C12N11 / 04(2006.01)1; C12N5 / 10(2006.01)1; C12Q 1 / 02(2006.01)1 FI: C12N11 / 04; C12N5 / 10; C12Q1 / 02 According to International Patent Classification (IPC) or to both national classification ar id IPC B. FIELDS SEARCHEDMinimum documentation searched (classification system followed by classification symbols)C12N11 / 04: C12N5 / 10; C12Q1 / 02Documentation searched other than minimum documentation to the extent that such documents are included in the fields searchedPublished examined utility model applications of Japan 1922-1996Published unexamined utility model applications of Japan 1971-2024Registered utility model specifications of Japan 1996-2024Published registered utility model applications of Japan 1994-2024Electronic data base consulted during the international search (name of data base and, where practicable, search terms used) J STPlus / J MEDPlus / JST75 80 (J Dream III)DOCUMENTS CONSIDERED TO BE RELEVANTCategory* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No. X A Y A JP 2005-046121 A (JAPAN SCIENCE AND TECHNOLOGY AGENCY) 24 February 2005 (2005-02-24) examples 1, 2, paragraph [0019] JP 2013-027376 A (KANZAKI, Ryohei) 07 February 2013 (2013-02-07) claims 1, paragraph [0005] 1-3,9-12, 14-15 4-8, 13, 16-23 1-13, 17, 23 14-16, 18-22 X Y JP 2010-029106 A (BIOROIS CO., LTD.) 12 February 2010 (2010-02-12) claims 1, 5, paragraphs [0003], [0005], [0013], [0015] 14-16, 18-22 1-13, 17, 23 X A WO 2015 / 199195 Al (NATIONAL UNIVERSITY CORPORATION NAGOYA UNIVERSITY) 30 December 2015 (2015-12-30) claims 1-2, example 3 14-15, 18-21 1-13, 16-17, 22-23| | Further documents are listed in the continuation of Box C. | Z | See patent family annex. * Special categories of cited documents: “T” later document published after the international filing date or priority “A” document defining the general state of the art which is not considered date and not in conflict with the application but cited to understand the to be of particular relevance principle or theory underlying the invention “D” document cited by the applicant in die international application “X” document of particular relevance; the claimed invention cannot be “E" earlier application orpatent but published on or after the international considered novel or cannot be considered to involve an inventive step filing date when the document is taken alone •SL” document which may throw doubts on priority claim(s) or which is “Y” document of particular relevance; the claimed invention cannot be cited to establish the publication date of another citation or other considered to involve an inventive step when the document is special reason (as specified) combined with one or more other such documents, such combination “O” document referring to an oral disclosure, use, exhibition or other being obvious to a person skilled in the art means document member of the same patent family “P” document published prior to the international filing date but later than the priority date claimed Date of the actual completion of the international search 18 July 2024 Date of mailing of the international search report 30 July 2024 Name and mailing address of the ISA / JP Japan Patent Office (ISA / JP) 3-4-3 Kasumigaseki, Chiyoda-ku, Tokyo 100-8915 Japan Authorized officer Telephone No.International application No.

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