JPH08338798A - Sugar concentration sensor - Google Patents

Abstract

PURPOSE: To measure sugar concentration at high response while suppressing the functional deterioration with time by coating the surface of crystal electrode in a crystal oscillator sensor with a polymer containing a boronic acid group. CONSTITUTION: A crystal 4 is connected with an electrode 5 and a lead 1 and bonded through a silicone-based adhesive to an acryl chamber while a supporting rod is bonded through an epoxy-based adhesive to a needle 2. The surface of crystal electrode is then coated with a methanol solution of polymer containing a boronic acid group by dipping, for example, and then it is dried. The polymer containing a boronic acid group is a polymer having a boronic acid in the side chain and produced through homopolymerization of vinyl monomer having a boronic acid group or copolymerization of vinyl monomer having a boronic acid group with a monomer copolymerable therewith. The glucose sensor is immersed into a solution to be measured and a frequency variation is converted into an electric signal and read out thus measuring sugar concentrator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sugar concentration measuring sensor for measuring a sugar concentration in a solution and a sugar concentration measuring method using the same.

[0002]

_2. Description of the Related Art As a sensor for measuring the concentration of sugar in a solution, a sensor for measuring O ₂ by an oxygen electrode on which glucose oxidase is immobilized, which is called an enzyme glucose sensor (Nature, vol.214, p.986 ( 1967)), which measures H ₂ O ₂ using a platinum electrode on which glucose oxidase is immobilized (Anal. Chim. Acta., Vol.64m p.439 (197).
3)), which measures I ⁻ with an iodine ion electrode on which glucose oxidase is immobilized (Anal. Chim. Acta., Vo
l.66, p.443 (1973)), using a platinum black / platinum electrode called a fuel cell type glucose sensor, glucose was converted to H ₂
By reacting with O e occurring when it comes to gluconic acid ^-.. Shall be measured as the current (Proc of 25th Ann Conf.on Eng.
in Med. and Biol., p.58 (1972)), which measures optical rotation at 546 nm using a laser beam called an optical glucose sensor (Diabetes Care, vol.5, p.254 (1982)),
There are known ones that measure infrared radiation of glucose molecules using laser light (Appl. Phys., Vol.17, p.1 (1978)) and the like.

Since the enzyme glucose sensor has a high substrate specificity for glucose, it has been extensively studied to measure the sugar concentration in a living body, but since an enzyme derived from a living body such as glucose oxidase is immobilized on an electrode and used. In addition, there was a problem that the enzyme was inactivated and the life of the electrode was short. The fuel cell type glucose sensor has a low substrate specificity for sugar, and the sensor output affects amino acids and the like, which is a big problem, and there are many problems to be solved. Similarly, the optical glucose sensor has a problem that it is not practical because the substrate specificity is not high and at the same time the analytical instrument connecting the sensors is large and the cost is high.

Further, a polymer having a boronic acid group is a sugar-responsive drug release complex (JP-A-4-124145, JP-A-4-124144, JP-A-3-204823, JP-A-5-204823).
-93019, JP-A-6-192609), a packing material for liquid chromatograph (JP-A-4-216459), a cell aggregation activator (JP-A-5-124970) and the like are known. Further, as a sugar measuring method using a boronic acid group-containing compound, a method for measuring a change in fluorescence intensity of anthrylboronic acid (J. Am. Chem. Soc., Vol. 114, p. 5874 (1992)), phenylboron A method for measuring the change in fluorescence intensity when a fluorescent substance is allowed to act in the presence of an acid polymer (J. Biochem., In Pre
ss) is known, but it is not known to use it as an electrode of a sugar concentration sensor.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a sugar concentration measuring sensor in which the function of measuring the sugar concentration does not decrease with the passage of time, and a method for measuring the sugar concentration having a fast sugar response rate.

[0006]

The present invention provides a sugar concentration measuring sensor characterized in that a crystal element-type sensor is coated with a boronic acid group-containing polymer in a crystal oscillator type sensor, and the sugar concentration measuring sensor. A method for measuring a sugar concentration, which is characterized by using a sensor. A well-known sensor can be used for the body portion of the crystal oscillator type sensor that can be used in the present invention.

The boronic acid group-containing polymer is a polymer having a boronic acid in the side chain, and a vinyl monomer having a boronic acid group can be homopolymerized or copolymerized with a vinyl monomer having a boronic acid group. It is obtained by copolymerizing with a monomer. Examples of the vinyl monomer having a boronic acid group include 4- (dihydroxyborono) styrene, 3- (meth) acrylamidophenylboronic acid, N- (4′-vinylbenzyl).
-4-Phenylboronic acid carboxamide, 3-((meth) acrylamidylglycylamide) phenylboronic acid, 3- (meth) acrylamide-2-trifluoromethylphenylboronic acid, 3- (meth) acrylamide-
4-pentafluoroethylphenylboronic acid, 5- (meth) acrylamido-2-heptafluoropropylphenylboronic acid, 5-((meth) acrylicamidylglycylamide) -2-heptafluoropropylphenylboronic acid, 5- (Meth) acrylamide-2,4,6-bis (heptafluoropropyl) phenylboronic acid, 3-
(Meth) acrylamide-2- (1,1,2,2,3,
3-hexafluoropropyl) phenylboronic acid, 3-
(Meth) acrylamide-4- (1-chloro-1,1,
2,2,3,3-hexafluoropropyl) phenylboronic acid, 5- (meth) acrylamide-2- (perfluoro-1,4-dimethyl2,5-dioxaoctyl) phenylboronic acid, and the like.

The monomer copolymerizable with the vinyl monomer having a boronic acid group is, for example, (meth) acryloylmorpholine, acrylic acid, 2-hydroxyethyl (meth) acrylate, N-vinyl lactone, (meth). Acrylic acid monoglycerol, methyl vinyl ether, maleic anhydride, C1-C30 alkyl (meth) acrylate, acrylonitrile, styrene, methylstyrene, chlorostyrene, vinyl acetate, vinyl propionate, vinyl pivalate, methyl (meth) acrylate, ethyl (Meth) acrylate, n-butyl (meth) acrylate, ethyl vinyl ether, n-butyl vinyl ether, vinyl chloride, vinylidene chloride, ethylene, isobutylene, acrylonitrile, allyl (meth) acrylate as a polyfunctional monomer, Chi glycol di (meth)
Acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, diallyl phthalate, divinylbenzene, methylenebis (acrylamide), vinylbenzylamine, aminostyrene, 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, 2-vinyl imidazole, N
-Methyl-2-vinylimidazole, N-vinylimidazole, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide, N, N-dimethylaminoethyl acrylate, N,
N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl acrylate, N, N-diethylaminoethyl methacrylate, N, N-dimethylaminopropyl acrylamide and quaternary salts thereof, N, N-
Dimethylaminopropyl methacrylamide and its quaternary ammonium salt, N, N-dimethylaminoethyl acrylate and its quaternary ammonium salt, dimethylaminoethyl methacrylate and its quaternary ammonium salt, N, N-diethylaminoethyl acrylate and its quaternary ammonium salt Salt, N, N-diethylaminoethyl methacrylate and its quaternary ammonium salt, N-
Examples of alkyl (meth) acrylamides include:
Examples thereof include N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, Nt-butylacrylamide.

The boronic acid group-containing polymer can be obtained by copolymerizing a vinyl monomer having a boronic acid group with a homopolymerizable or copolymerizable monomer. In this case, a general radical polymerization method is used. Can be adopted, for example, solution polymerization,
It can be carried out by known techniques such as bulk polymerization, emulsion polymerization and suspension polymerization. The molar ratio of the vinyl monomer having a boronic acid group to the copolymerizable monomer when obtaining the copolymer is such that the copolymerizable monomer is 1 mol with respect to 1 mole of the vinyl monomer having a boronic acid group. Body to 0.03 to 100 mol, preferably 0.5
To 20 moles.

Examples of the polymerization initiator include benzoyl peroxide, lauroyl peroxide, diisopropylperoxydicarbonate, t-butylperoxy-2-ethylhexanoate, t-butylperoxypivalate and t.
-Butylperoxydiisobutyrate, azobisisobutyronitrile, 2,2'-azobis (2-aminopropane) dihydrochloride, 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis [2- (5-Methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2 ′
-Azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobisisobutyramide dihydrate, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-amidinopropane) dihydrochloride, persulfate, bisulfite and the like can be used. The amount of the polymerization initiator used is 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the total monomers.

The above-mentioned copolymerization conditions are such that the polymerization system is optionally in an atmosphere of an inert gas such as nitrogen, carbon dioxide or helium, the polymerization temperature is 0 to 100 ° C., the polymerization time is 0.1 to 7
2 hours. The molecular weight of the copolymer obtained by the polymerization can be adjusted by the polymerization temperature, the amount of the initiator used, and the like. In the case of a linear chain, the number average molecular weight is preferably 1,000 to 1,000,000, more preferably 10,000 to 100,000.

The method of coating the boronic acid group-containing polymer on the crystallite electrode surface is a dipping method, a spin casting method, or the like. Sugars that can be measured by the sugar concentration measuring sensor of the present invention are, for example, glucose, fructose, mannose and the like.

As a method of measuring the concentration in a solution using the sugar concentration measuring sensor of the present invention, for example, a frequency change caused by immersing the sugar concentration measuring sensor in the solution whose sugar concentration is to be measured is known. It can be measured by converting it into an electrical signal and reading it.

[0014]

EFFECT OF THE INVENTION The sugar concentration measuring sensor and the sugar concentration measuring method of the present invention enable a sugar concentration measuring method which is less likely to deteriorate in function over time and has a fast sugar responsiveness.

[0015]

【Example】

[Reference Example] Preparation of polymer containing boronic acid group 3.1 × 10 ^-3 mol of N, N-dimethylacrylamide, 3.1 × 10
^-3 mol 3-methacrylamidophenylboronic acid, 6.3 x 10
^-3 mol N, N-dimethylaminopropyl acrylamide,
3.1 × 10 ⁻³ mol of butyl methacrylate and 20 mg of azobis (isobutylnitrile) were dissolved in 16.5 ml of methanol, and the mixture was polymerized by stirring at 80 ° C. for 3 hours under a nitrogen atmosphere. Next, reprecipitation was performed three times using diethyl ether, followed by filtration and drying under reduced pressure to prepare a boronic acid group-containing polymer for coating.

Example 1 Preparation of Sugar Concentration Sensor A conductor was connected to a crystal oscillator having a diameter of 8 mm and a thickness of 0.1475 mm,
According to FIG. 1, it was fixed to the acrylic chamber with a silicone adhesive. Furthermore, the support rod and the needle for making the pressure in the chamber atmospheric pressure were fixed with an epoxy adhesive.
Next, the crystal oscillator surface was coated with a methanol solution of the boronic acid group-containing polymer obtained in Reference Example, naturally dried at room temperature for 1 hour, and then dried under reduced pressure for 2 hours. Two types of film thickness, 140 ng / mm ² (sensor A) and 60 ng / mm ² (sensor B), were obtained by changing the concentration of the polymer solution.

<Evaluation of Performance as Sugar Concentration Sensor> After immersing the sugar concentration sensors A and B obtained in Example 1 in distilled water so that the crystal oscillator part could be used, the glucose concentrations were 0, 10, 64, 125, 190, 250 and 300, respectively. Glucose was added to ng / ml (sensor A) and 0,2,5,25,50,64,75 ng / ml (sensor B), and a change in frequency was detected using a commercially available oscillator. The results are shown in Table 1 and Table 2.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

[Brief description of drawings]

FIG. 1 is a schematic view of an embodiment of a sugar concentration sensor of the present invention.

[Explanation of symbols]

 1: Conductive wire 2: Needle 3: Epoxy resin 4: Crystal 5: Electrode 6: Acrylic chamber

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ken Suzuki, 242-103 Noborito Shinmachi, Tama Ward, Kawasaki City, Kanagawa Prefecture

Claims (2)

[Claims] 1. A sensor for measuring sugar concentration, characterized in that in a crystal oscillator type sensor, a boronic acid group-containing polymer is coated on a crystallite electrode surface. 2. A method for measuring sugar concentration, which comprises using the sugar concentration measuring sensor according to claim 1.