JP5751580B2 - Methoxyoligoethylene glycol-silane compound surface modification material - Google Patents

Description

  The present invention relates to a silane compound into which methoxy oligoethylene glycol capable of thin film modification on the surface of various materials is introduced, a method for producing the same, and a thin film surface modifying material using the methoxy oligo ethylene glycol-silane compound.

In biosensor development, since a protein contained in a measurement sample is non-specifically adsorbed on the surface of a sensing element to reduce the sensing function, a surface-modifying material that suppresses non-specific protein adsorption is required. Known functional groups introduced into such a surface modifying material include polyether compounds such as polyethylene glycol and zwitter ion compounds such as phosphorylcholine. In particular, polyethylene glycol has been widely studied as a biocompatible surface modifying material that suppresses nonspecific adsorption of proteins because of its ease of handling (Patent Documents 1 and 2).
In the development of high-sensitivity biosensors such as surface plasmon resonance (SPR) sensors and waveguide mode sensors, surface modification with the thinnest possible film, including monomolecular films, to detect molecules on the sensing element surface with higher sensitivity Is required. Various functional groups that react with the modified surface are introduced into the surface modifying material. By introducing a thiol as a functional group, it is possible to easily modify the monomolecular film on the gold surface. Therefore, various surface modifying materials into which a thiol is introduced have been developed and used in various fields. On the other hand, silane-introduced compounds are known as more versatile surface-modifying materials because they can modify the surface of various materials such as glass, cloth, plastic, and carbon, and can also be modified with monomolecular films. ing.
Polyethylene glycol surface-modified materials with thiol or silane introduced have been developed and marketed as surface-modifying materials that suppress nonspecific adsorption of proteins, but because of the high molecular weight, the surface of the modified surface becomes thicker and high-sensitivity sensing It is known that it can be a problem in the development of devices. Thiol-introduced oligoethylene glycol and methoxy oligoethylene glycol surface modification materials have been developed as surface modification materials for thin film construction that can solve this problem, and by forming high-density monomolecular films such as self-assembled films, It has been reported that it exhibits a non-specific adsorption inhibiting function (Non-Patent Documents 1 and 2). However, the surface of the sensing element that can be modified is limited to gold, and it is difficult to say that the ability to suppress nonspecific adsorption of proteins and the like to samples used in the medical field such as serum is not sufficient. Accordingly, it has been desired to develop a surface modifying material that can be applied to the surface of a material other than metal and that can modify the surface of a base material of a wider range of materials.

JP 2007-139588 A JP 2008-1794 A

S. Herrwerth, W. Eck, S. Reinhardt, and M. Grunze, J. Am. Chem. Soc., 2003, 125, 9359-9366. Z. Zhang, M. Zhang, S. Chen, T. A. Horbett, B. D. Ratner, and S. Jiang, Biomaterials, 2008, 29, 4285-4291.

  The present invention can modify the surface of a thin film such as a monomolecular film, exhibits a sufficient effect of suppressing nonspecific adsorption of proteins and the like even when a sample such as serum is used, and can be used for various substrates such as glass and plastic. An object of the present invention is to provide a surface modifying material capable of modifying the surface.

In order to effectively suppress non-specific adsorption of proteins and the like, the present inventors have demonstrated that high-density monomolecular film modification such as a self-assembled film is effective, and for such modification, hydrogen bonding is performed. In view of the effectiveness of introducing amide groups to form, various methoxy oligoethylenes having amide groups that form hydrogen bonds by reacting carboxylic acid derivatives having methoxy oligoethylene glycol with silane compounds having amino groups Glycol-silane derivatives were synthesized. As a result of earnest research on these derivatives and their thin film forming ability, it was confirmed that the methoxy oligoethylene glycol-silane compound represented by the following general formula (Chemical Formula 1) can be modified with a high-density monomolecular film comparable to a self-assembled film. I found it. By using the methoxy oligoethylene glycol-silane compound, it became possible to modify the sensing substrate of various materials on the surface of the thin film and effectively suppress nonspecific adsorption of proteins. That is, the present invention provides a methoxy oligoethylene glycol-silane compound that is promising as a surface modification material that contributes to the development of a highly sensitive biosensor and suppresses nonspecific adsorption of proteins.
The novel compound of the present invention can be described by the following general formula (Chemical Formula 1), and can be synthesized by reacting the following (Chemical Formula 2) and (Chemical Formula 3) (Reaction Formula 1).
(Wherein X _{1 to} X ₃ each independently represent a halogen, an alkoxy group having 1 to 3 carbon atoms, or an alkyl group having 1 to 3 carbon atoms, provided that at least one of X _{1 to} X ₃ Is a halogen or an alkoxy group having 1 to 3 carbon atoms, and a is an integer of 1 to 10.
R _{is, - (CH 2) m -} (OCH 2 CH 2) n - represents a. m is an integer of 2 to 10, and n is an integer of 0 to 5. )
(Wherein, a is the same as defined in (Chemical Formula 1), and Y represents a carboxylic acid active group.)
(Wherein X _{1 to} X ₃ and R are the same as defined in (Chemical Formula 1).)

That is, the present invention is as follows.
[1] A methoxy oligoethylene glycol-silane compound represented by the following (Chemical Formula 1);
(Wherein X _{1 to} X ₃ each independently represent a halogen, an alkoxy group having 1 to 3 carbon atoms, or an alkyl group having 1 to 3 carbon atoms, provided that at least one of X _{1 to} X ₃ Is a halogen or an alkoxy group having 1 to 3 carbon atoms, and a is an integer of 1 to 10.
R _{is, - (CH 2) m -} (OCH 2 CH 2) n - represents a. m is an integer of 2 to 10, and n is an integer of 0 to 5. )
[2] A method for producing a methoxy oligoethylene glycol-silane compound (chemical formula 1) according to [1],
Represented by the following (Chemical Formula 2)
(Wherein, a is the same as defined in (Chemical Formula 1), and Y represents a carboxylic acid active group.)
And represented by the following (Chemical Formula 3)
(Wherein, X _{1 to} X ₃ and R are the same as defined in (Chemical Formula 1).)
And reacting.
[3] A thin film comprising the methoxy oligoethylene glycol-silane compound according to [1], wherein at least a part of the surface of the device or its substrate is modified.
[4] A device having at least one surface modified with the methoxy oligoethylene glycol-silane compound according to [1] or a substrate thereof.
[5] The device according to [4] or the base material thereof, wherein the device is a waveguide mode sensor and the base material is a biosensing element used in the device.

  Using the methoxy oligoethylene glycol-silane compound of the present invention, it is possible to modify the surface of a sensing substrate made of various materials. The modified surface shows an excellent non-specific adsorption suppressing effect for proteins and the like, and is promising as a material for constructing a highly sensitive biosensing element.

Nonspecific adsorption suppression effect on control serum The vertical axis represents the reflectance peak wavelength shift value (unit: nm). In the figure, M3EG represents methoxytriethyleneglycol-triethoxysilane, and M4EG represents methoxytetraethyleneglycol-triethoxysilane. , M5EG represents methoxypentaethylene glycol-triethoxysilane.

1. About the methoxy oligoethylene glycol-silane compound of the present invention The methoxy oligoethylene glycol-silane compound of the present invention is a novel compound not described in any literature, and it is possible to modify the surface of a sensing element of various materials with a thin film surface. The modified surface shows an excellent non-specific adsorption suppressing effect for proteins and the like, and is promising as a material for constructing a highly sensitive biosensing element. In this invention, in order to evaluate the protein non-specific adsorption inhibitory effect of the synthesized methoxy oligoethylene glycol-silane compound, the silica surface of the waveguide mode sensor chip is modified, and the protein non-specific adsorption inhibitory effect by the waveguide mode sensor. Evaluated.
The methoxy oligoethylene glycol-silane compound of the present invention is represented by the following general formula (Chemical Formula 1).
In the above _formula, X 1 to X ₃ each independently represent a halogen, an alkoxy group having 1 to 3 carbon atoms, or an alkyl group having 1 to 3 carbon atoms. However, at least one of X _{1 to} X ₃ is a halogen or an alkoxy group having 1 to 3 carbon atoms. Here, the alkoxy group is preferably a methoxy group or an ethoxy group. a is an integer of 1 to 10, preferably a = 2 to 5.
R _{is, - (CH 2) m -} (OCH 2 CH 2) n - represents a. m is an integer of 2 to 10, and preferably m = 2 to 6. n is an integer of 0-5, preferably n = 0-2.
Note that the symbols and symbols used in the chemical formulas and reaction formulas in this specification all have the same meaning as long as they are the same symbols and symbols.

2. Production method of methoxy oligoethylene glycol-silane compound of the present invention Hereinafter, the production method of methoxy oligoethylene glycol-silane compound of the present invention will be described.
(2-1) Synthesis of oligoethylene glycol carboxylic acid ethyl ester derivative First, diazoacetic acid ethyl ester is synthesized from glycine ethyl ester hydrochloride according to the following reaction formula.
Although the manufacturing method of diazoacetic acid ethyl ester is well-known, since it is an unstable compound, it is not marketed. For example, glycine ethyl ester hydrochloride and sodium nitrite are dissolved in a water-dichloromethane mixed solvent, and diluted sulfuric acid is added and allowed to react with stirring. The produced diazoacetic acid ethyl ester can be obtained in a high yield of 80% or more by sequentially taking out by solvent extraction into a dichloromethane layer.
Then, according to the following reaction formula, the diazoacetic acid ethyl ester is represented by “H— (OCH ₂ CH ₂ ) _b —OR ₁ ”, specifically “H— (OCH ₂ CH ₂ ) _b —OCH ₃ ”. It reacts with oligoethylene glycol monomethyl ether or oligoethylene glycol represented by “H— (OCH ₂ CH ₂ ) _b —OH”. In these formulas, R ₁ is a methyl group or hydrogen. b is 1 to 10 and is an integer of a or less, preferably b = 2 to 5.
Specifically, a method may be employed in which the oligoethylene glycol monomethyl ether or oligoethylene glycol is added to a dichloromethane solution of diazoacetic acid ethyl ester, and a dichloromethane solution of boron trifluoride ethyl ether complex is dropped and reacted.
Then, after distilling off dichloromethane, purification with known means such as vacuum distillation, the desired “methoxy oligoethylene glycol carboxylic acid ethyl ester” or “oligoethylene glycol carboxylic acid ethyl ester” is obtained in a yield of 60% or more. Can be obtained.
The resulting carboxylic acid ester-containing oligoethylene glycol derivative can be represented by the following (Chemical Formula 4), that is, (Chemical Formula 5) or (Chemical Formula 6).

(2-2) Synthesis of methoxy oligoethylene glycol carboxylic acid According to the following reaction formula, the target methoxy oligo ethylene glycol carboxylic acid or oligo ethylene glycol carboxylic acid is obtained by subjecting the carboxylic acid ester-containing oligo ethylene glycol derivative to alkali hydrolysis. An acid can be obtained.
The obtained methoxy oligoethylene glycol carboxylic acid can be represented as (Chemical Formula 7), and the oligoethylene glycol carboxylic acid can be represented as (Chemical Formula 8).
In the case of the oligoethylene glycol carboxylic acid, it is further reacted with an oligoethylene glycol monomethyl ether derivative represented by “Z— (CH ₂ CH ₂ O) _c —CH ₃ ” according to the following reaction formula. In these formulas, Z represents a reactive group that reacts with a hydroxyl group to form an ether bond, such as halogen, tosylate, and mesylate. c is an integer of 0 to 9 and less than a, preferably b + c = 2 to 5, and when c = 0, a methyl derivative is obtained.
Specifically, a method in which a THF solution of the oligoethylene glycol monomethyl ether derivative is dropped and reacted with a THF solution of oligoethylene glycol carboxylic acid and sodium hydride can be employed.
Then, after distilling off THF, the target methoxy oligoethylene glycol carboxylic acid can be obtained by purification by a known means such as a silica gel column.

(2-3) Synthesis of methoxy oligoethylene glycol-silane compound To obtain the methoxy oligoethylene glycol-silane compound which is the final object of the present invention, methoxy oligoethylene glycol was synthesized by the synthesis method of (2-2) above. Along with the introduced carboxylic acid derivative, a silane derivative having an amino group represented by the following (Chemical Formula 3) is required, but the silane derivative is almost commercially available. For example, 3-aminopropyltrihalogenated silane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and the like are commercially available from Tokyo Chemical Industry Co., Ltd. In this example, 3-aminopropyltriethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) is used.
In the above formula, X _{1 to} X ₃ and R are the same as defined in (Chemical Formula 1).
Then, the following (chemical formula 2) synthesized from the silane derivative of (chemical formula 3) according to the above (2-2) is reacted according to the following (reaction formula 1) to thereby obtain the desired methoxy oligoethylene glycol-silane compound. Can be obtained.
In the above formula, a is the same as defined in (Chemical Formula 1), and Y represents a carboxylic acid active group. The carboxylic acid active group is well known to those skilled in the art, and typically, halogen, hydroxysuccinimide, DCC adduct (dicyclohexylcarbodiimide adduct) and the like are used.
This reaction can be carried out using a basic catalyst such as triethylamine, pyridine, or dimethylaminopyridine as a catalyst. As the catalyst, triethylamine is preferably used.
The solvent used is an organic solvent such as dichloromethane, tetrahydrofuran, benzene, acetonitrile, etc., preferably tetrahydrofuran is used. The reaction ratio between the carboxylic acid derivative into which methoxy oligoethylene glycol is introduced and the silane derivative may be about 0.5 to 2 mol, preferably about equimolar with respect to 1 mol of the former. The amount of the catalyst used may be 1 to 5 mol, preferably about 2 mol, per mol of the carboxylic acid derivative into which methoxy oligoethylene glycol is introduced. The reaction temperature is about 0 to 50 ° C., preferably room temperature (25 ° C.), and the reaction time is about 12 hours.
The methoxy oligoethylene glycol-silane compound thus obtained is easily isolated by a conventional purification method such as HPLC method, column chromatography method, thin layer chromatography method, or a combination of these methods. It can be purified.
Moreover, it can confirm by NMR, mass spectrometry, etc. that the target object of this invention was synthesize | combined.

3. Method for forming thin film on substrate surface using methoxy oligoethylene glycol-silane compound of the present invention The methoxy oligoethylene glycol-silane compound of the present invention is used for non-specific adsorption of proteins such as peptide arrays, antibody arrays, DNA chips, etc. Thin films can be formed on the surfaces of various materials used for various sensitive biosensing elements and chips that require strict exclusion, such as silica, silicon nitride, oxidized plastic, and oxidized carbon chips. And since it shows a very high non-specific adsorption suppressing function of protein, it can be effectively used as a surface modification material for a wide range of biosensing elements. In addition to these sensing elements, it can also be used on the surface of fibers and stainless steel, and can also be widely used as a coating material for the outer surface and inner surface of medical devices and food utensils.
In the present invention, covering the surface of the base material with a thin film that forms a covalent bond with the silyl group of the methoxy oligoethylene glycol-silane compound of the present invention is referred to as “surface modification”. In addition to the immersion method, coating and spraying methods can be used as surface modification methods, so the target substrate can be of any shape and size, and a non-protein-specific adsorption suppression function is required. It is possible to modify only part of the surface. Various modifications in the present invention may be expressed as “apparatus or its substrate”.

The technique for thin-film modification of the chip surface using the methoxy oligoethylene glycol-silane compound of the present invention may be selected as an optimum technique for each target sensing element and chip, but as a typical technique, After completely cleaning and drying the base material and chip to be modified, the base material, chip and the like are immersed in the solution of the methoxy oligoethylene glycol-silane compound of the present invention, followed by washing and drying. Instead of the immersion process, a coating or spraying method may be used. As the solvent for the methoxy oligoethylene glycol-silane compound, any organic solvent that does not decompose the silane compound can be used. Typical examples include toluene, ethanol, and THF. However, when the material of the base material is plastic, toluene or THF having plastic solubility cannot be used, and therefore, an alcohol solvent such as ethanol is preferable.
For surface coating of normal medical devices and food appliances, it is possible to easily modify the surface by the thin film modification procedure described above, but when used for highly sensitive biosensors such as waveguide mode sensors, When stringency is required, controlled thin film formation such as a self-assembled monomolecular film is required. As such a more difficult procedure for monomolecular film modification, for example, it can be carried out as follows.
(1) Ultrasonic cleaning in acetone for 10 minutes
(2) Ultrasonic cleaning in ethanol for 5 minutes
(3) Vacuum drying for 1 hour
(4) Immerse the synthesized surface modification material in 1 mM toluene solution
(5) Ultrasonic cleaning in acetone for 1 minute, followed by ethanol cleaning Here, the immersion time and temperature of the chip in (4) above depend on the methoxy oligoethylene glycol-silane compound used, and in the case of M3EG, 0 ° C. ˜24 to 72 hours at room temperature, preferably 48 hours, and in the case of M4EG and M5EG, it is 8 to 36 hours, preferably 15 to 24 hours under heating conditions (50 ° C.).
The formation of the monomolecular film can be confirmed by a film thickness measurement method such as XPS (X-ray photoelectron spectroscopy) or ellipsometry (polarization analysis).

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not limited to it.
(Example 1) Synthesis of methoxytriethylene glycol-triethoxysilane (M3EG) (1-1) Synthesis of ethyl diazoacetate
A three-necked flask (1 L) was charged with 38.1 g (0.55 mol) of sodium nitrite, 68.4 g (0.49 mol) of glycine ethyl ester hydrochloride, 1.36 g of sodium acetate, and 250 ml of water. Meanwhile, 200 ml of 10 wt% aqueous sulfuric acid solution and 500 ml of 10 wt% aqueous sodium carbonate solution were prepared and cooled to 0 ° C. in the same manner. Add 80 ml of cooled dichloromethane and 3 ml of 10 wt% sulfuric acid aqueous solution and stir at 0 ° C. for 5 minutes, then separate the dichloromethane layer with a separatory funnel. And stored at 0 ° C. 80 ml of cooled dichloromethane was added again, and 15 ml of 10 wt% sulfuric acid aqueous solution was added dropwise over 3 minutes. After stirring for 3 minutes at 0 ° C., the dichloromethane layer was separated with a separatory funnel. After washing with 50 ml of a cooled aqueous sodium carbonate solution, the solution was stored at 0 ° C. This operation was repeated (7 to 8 times) until the yellow color disappeared in the dichloromethane layer. The collected dichloromethane layers were combined, washed with an equal amount of water, dehydrated overnight using anhydrous sodium sulfate, and used in the next reaction as a solution.
Yellow liquid crude yield 80%

(1-2) Synthesis of methoxytriethylene glycol carboxylic acid ethyl ester
A three-necked flask (2 L) was charged with 164 g (1.18 mol) of triethylene glycol monomethyl ether, 45.1 g of crude diazoacetic acid (392 mmol, dichloromethane solution) and 1.2 L in total of dichloromethane, and heated to reflux. Boron trifluoride ethyl ether complex ether solution 1.5 mL (47 wt%) in dichloromethane 40 mL was added dropwise over 30 minutes at such a rate that the reflux could be maintained, and the mixture was further heated under reflux for 3 hours. After allowing to cool, the reaction solution was poured into 1 L of water, the dichloromethane layer was separated, and the dichloromethane layer was washed once again with 1 L of water. Dichloromethane was distilled off and the desired product was purified by distillation under reduced pressure.
A colorless liquid, b. p. 115-120 ° C / 0.2mmHg
Yield 65%

(1-3) Synthesis of methoxytriethylene glycol carboxylic acid
In a three-necked flask (300 mL), 12.5 g (50 mmol) of methoxytriethylene glycol glycol carboxylic acid ethyl ester and 100 mL of THF were added and stirred at room temperature. 100 mL of an aqueous solution of 10.0 g (250 mmol) of sodium hydroxide was added and heated to reflux for 12 hours. After cooling, the reaction mixture was acidified with concentrated hydrochloric acid, THF and water were distilled off, and 100 mL of benzene was added to the residue to remove insoluble matters. Benzene was distilled off, dried under reduced pressure and used as it was in the next reaction.
Colorless liquid crude yield 97%

(1-4) Synthesis of methoxytriethylene glycol carboxylic acid chloride
In an eggplant flask (200 mL), 1.11 g (5 mmol) of crude methoxytriethylene glycol carboxylic acid, 1.27 g (10 mmol) of oxalyl chloride and 80 mL of benzene were added and stirred at room temperature. 4 drops of DMF were added and stirred at room temperature for 6 hours. Benzene and oxalyl chloride were distilled off, dried under reduced pressure, and used directly in the next reaction.
Light brown liquid crude yield 100%

(1-5) Synthesis of methoxytriethylene glycol-triethoxysilane
An eggplant flask (300 mL) was charged with 1.08 g (6 mmol) of aminopropyltriethoxysilane, 1.21 g (12 mmol) of triethylamine and 100 mL of dehydrated THF in a nitrogen atmosphere and stirred at 0 ° C. 30 mL of a dehydrated THF solution of 1.20 g (5 mmol) of crude methoxytriethylene glycol carboxylic acid chloride was added dropwise and stirred at room temperature for 12 hours. THF was distilled off, and the desired product was purified by a silica gel column (chloroform: ethanol = 100: 0 → 0.5).
Colorless liquid yield 79%
¹ H-NMR; (CDCl ₃ , 500 MHz) δ: 0.60 (2H, t, J = 8.48 Hz), 1.18 (9H, t, J = 7.10 Hz), 1.55-1.65 (2H, m), 3.24 (2H, q, J = 6.88 Hz), 3.34 (3H, s), 3.48 to 3.54 (2H, m), 3.58 to 3.68 (10H, m), 3.78 (6H, q, J = 7.02 Hz), 3.95 (2H, s), 3.99 (1H, t, J = 5.70 Hz)

(Example 2) Synthesis of methoxytetraethylene glycol-triethoxysilane (M4EG) (2-1) Synthesis of triethylene glycolic acid ethyl ester
A three-necked flask (2 L) was charged with 208 g (1.96 mol) of diethylene glycol, 45.1 g of crude diazoacetic acid (392 mmol, dichloromethane solution) and 1.2 L in total of dichloromethane, and heated to reflux. Boron trifluoride ethyl ether complex ether solution 1.5 mL (47 wt%) in dichloromethane 40 mL was added dropwise over 30 minutes at such a rate that the reflux could be maintained, and the mixture was further heated under reflux for 3 hours. After allowing to cool, the reaction solution was poured into 1 L of water, and the dichloromethane layer was separated. The aqueous layer was extracted twice with 400 mL of chloroform. Dichloromethane and chloroform were distilled off, and the desired product was purified by distillation under reduced pressure.
A colorless liquid, b. p. 98-102 ° C / 0.25mmHg
Yield 90%

(2-2) Synthesis of potassium triethylene glycolate
A three-necked flask (300 mL) was charged with 3.84 g (20 mmol) of triethylene glycol glycolic acid ethyl ester and 100 mL of ethanol and stirred at room temperature. 100 mL of an aqueous solution of 5.52 g (40 mmol) of potassium carbonate was added and heated to reflux for 12 hours. After allowing to cool, ethanol and water were distilled off, dried under reduced pressure, and used as such in the next reaction.
Colorless solid crude yield 100%

(2-3) Synthesis of diethylene glycol monomethyl ether tosylate
A three-necked flask (300 mL) was charged with 6.01 g (50 mmol) of diethylene glycol monomethyl ether, 7.00 g (175 mmol) of sodium hydroxide, 35 mL of THF, and 35 mL of water, and cooled with ice. 50 mL of a THF solution of 11.44 g (60 mmol) of p-toluenesulfonyl chloride was added dropwise over 2 hours, and the mixture was further stirred at 0 ° C. for 2 hours and at room temperature for 12 hours. The reaction solution was poured into 200 mL of 5 wt% hydrochloric acid at 0 ° C. and extracted with 300 mL of chloroform. The chloroform layer was washed with 200 mL of water and dehydrated with anhydrous sodium sulfate. Chloroform was distilled off, dried under reduced pressure and used as it was in the next reaction.
Brown liquid crude yield 100%

(2-4) Synthesis of methoxytetraethylene glycol carboxylic acid
A three-necked flask (300 mL) was charged with 2.00 g (60%, 50 mmol) of sodium hydride and 200 mL of THF, and stirred at room temperature. 9.36 g of potassium triethylene glycolate (20 mmol, including 5.54 g of potassium carbonate) was added while paying attention to heat generation, and the mixture was heated to 100 ° C. 50 mL of a THF solution of 8.23 g (30 mmol) of diethylene glycol methyl ether tosylate was added dropwise, and the mixture was heated to reflux for 12 hours. After allowing to cool, methanol was added to the reaction solution to decompose excess sodium hydride. THF was distilled off, and the resulting residue was poured into 100 mL of 5 wt% hydrochloric acid and extracted five times with 100 mL of chloroform. Chloroform was distilled off, and 5 mL of a 5 wt% aqueous sodium hydroxide solution was added to the resulting residue, followed by stirring at room temperature for 12 hours. The reaction mixture was acidified by adding concentrated hydrochloric acid while paying attention to heat generation, and extracted five times with 100 mL of chloroform. Chloroform was distilled off, and the target product was purified with a silica gel column (chloroform: methanol = 100: 1 → 25).
Light brown liquid yield 53%

(2-5) Synthesis of methoxytetraethylene glycol carboxylic acid chloride
In an eggplant flask (200 mL), 266 mg (1 mmol) of methoxytetraethylene glycol carboxylic acid, 254 mg (2 mmol) of oxalyl chloride, and 30 mL of benzene were added and stirred at room temperature. 3 drops of DMF was added and stirred at room temperature for 6 hours. Benzene and oxalyl chloride were distilled off, dried under reduced pressure, and used directly in the next reaction.
Light brown liquid crude yield 100%

(2-6) Synthesis of methoxytetraethylene glycol-triethoxysilane
In a three-necked flask (100 mL), 266 mg (1.2 mmol) of aminopropyltriethoxysilane, 151 mg (1.5 mmol) of triethylamine, and 30 mL of dehydrated THF were placed in a nitrogen atmosphere and stirred at 0 ° C. 20 mL of a dehydrated THF solution of 285 mg (1 mmol) of crude methoxytetraethylene glycol carboxylic acid chloride was added dropwise and stirred at room temperature for 12 hours. THF was distilled off, and the target product was purified with a silica gel column (chloroform: ethanol = 100: 1 → 5).
Colorless liquid yield 36%
¹ H-NMR; (CDCl ₃ , 500 MHz) δ: 0.62 (2H, t, J = 8.48 Hz), 1.21 (9H, t, J = 7.10 Hz), 1.58 to 1.67 (2H, m), 3.27 (2H, q, J = 6.88 Hz), 3.37 (3H, s), 3.52 to 3.56 (2H, m), 3.61 to 3.68 (14H, m), 3.81 (6H, q, J = 7.03 Hz), 3.97 (2H, s), 6.97 (1H, t, J = 6.65 Hz)

(Example 3) Synthesis of methoxypentaethylene glycol-triethoxysilane (M5EG) (3-1) Synthesis of triethylene glycol monomethyl ether tosylate
A three-necked flask (300 mL) was charged with 8.21 g (50 mmol) of triethylene glycol monomethyl ether, 7.00 g (175 mmol) of sodium hydroxide, 35 mL of THF, and 35 mL of water, and cooled with ice. 50 mL of a THF solution of 11.44 g (60 mmol) of p-toluenesulfonyl chloride was added dropwise over 2 hours, and the mixture was further stirred at 0 ° C. for 2 hours and at room temperature for 12 hours. The reaction solution was poured into 200 mL of 5 wt% hydrochloric acid at 0 ° C. and extracted with 300 mL of chloroform. Chloroform was distilled off, dried under reduced pressure and used as it was in the next reaction.
Brown liquid crude yield 96%

(3-2) Synthesis of methoxypentaethylene glycol carboxylic acid
A three-necked flask (300 mL) was charged with 2.00 g (60%, 50 mmol) of sodium hydride and 200 mL of THF, and stirred at room temperature. 9.36 g of potassium triethylene glycolate (20 mmol, including 5.54 g of potassium carbonate) was added while paying attention to heat generation, and the mixture was heated to 100 ° C. 50 mL of a THF solution of 9.55 g (30 mmol) of triethylene glycol methyl ether tosylate was added dropwise, and the mixture was heated to reflux for 12 hours. After allowing to cool, methanol was added to the reaction solution to decompose excess sodium hydride. THF was distilled off, and the resulting residue was poured into 100 mL of 5 wt% hydrochloric acid and extracted five times with 100 mL of chloroform. Extracted 5 times with 100 mL of chloroform. Chloroform was distilled off, and 5 mL of a 5 wt% aqueous sodium hydroxide solution was added to the resulting residue, followed by stirring at room temperature for 12 hours. The reaction mixture was acidified by adding concentrated hydrochloric acid while paying attention to heat generation, and extracted five times with 100 mL of chloroform. Chloroform was distilled off, and the target product was purified with a silica gel column (chloroform: methanol = 100: 1 → 25).
Light brown liquid yield 33%

(3-3) Synthesis of methoxypentaethylene glycol carboxylic acid chloride
In an eggplant flask (200 mL), 310 mg (1 mmol) of methoxypentaethylene glycol carboxylic acid, 254 mg (2 mmol) of oxalyl chloride, and 30 mL of benzene were added and stirred at room temperature. 3 drops of DMF was added and stirred at room temperature for 6 hours. Benzene and oxalyl chloride were distilled off, dried under reduced pressure, and used directly in the next reaction.
Light brown liquid crude yield 100%

(3-4) Synthesis of methoxypentaethylene glycol-triethoxysilane
In a three-necked flask (100 mL), 266 mg (1.2 mmol) of aminopropyltriethoxysilane, 151 mg (1.5 mmol) of triethylamine, and 30 mL of dehydrated THF were placed in a nitrogen atmosphere and stirred at 0 ° C. 20 mL of a dehydrated THF solution of 329 mg (1 mmol) of crude methoxypentaethylene glycol carboxylic acid chloride was added dropwise and stirred at room temperature for 12 hours. THF was distilled off, and the target product was purified with a silica gel column (chloroform: ethanol = 100: 1 → 5).
Colorless liquid yield 38%
¹ H-NMR; (CDCl ₃ , 500 MHz) δ: 0.63 (2H, t, J = 8.48 Hz), 1.22 (9H, t, J = 7.08 Hz), 1.58 to 1.67 (2H, m), 3.28 (2H, q, J = 7.08 Hz), 3.37 (3H, s), 3.52 to 3.57 (2H, m), 3.61 to 3.69 (18H, m), 3.81 (6H, q, J = 7.02 Hz), 3.97 (2H, s), 6.97 (1H, t, J = 6.18 Hz)

(Example 4) Evaluation of protein non-specific adsorption inhibition function of methoxy oligoethylene glycol-silane compound Using the synthesized M3EG, M4EG, and M5EG, the silica surface of the waveguide mode sensor chip was modified to inhibit protein non-specific adsorption on the modified surface. The effect was evaluated using control serum. The surface modification of the chip is
(1) Ultrasonic cleaning in acetone for 10 minutes
(2) Ultrasonic cleaning in ethanol for 5 minutes
(3) Vacuum drying for 1 hour
(4) Immerse the synthesized surface modification material in 1 mM toluene solution
(5) Ultrasonic cleaning in acetone for 1 minute followed by ethanol cleaning was performed. The immersion conditions for chip surface modification are 48 hours of immersion at room temperature for M3EG, 15 hours of immersion at 50 ° C. for M4EG, and 24 hours at 50 ° C. for M5EG.
The wavelength shift measurement of the reflectance peak in the waveguide mode sensor is performed by first measuring the peak wavelength in PBS, immersing the chip in control serum for 5 minutes, then washing it with an equal volume of PBS solution three times, and again measuring the peak wavelength. Measurement was performed to determine the wavelength shift value.
FIG. 1 shows the reflectance peak wavelength shift value when the surface is modified with each compound. As a comparison object, the wavelength shift value when the surface is not modified is also shown in the figure. When the surface was not modified, a large peak wavelength shift value was observed due to nonspecific adsorption of proteins contained in the control serum. On the other hand, in the case of surface modification, non-specific adsorption was effectively suppressed, and in particular, the results showed that non-specific adsorption was almost completely suppressed in M3EG and M4EG (FIG. 1).

From the above results, it was revealed that the compounds synthesized in the present invention, M3EG, M4EG, and M5EG are all useful as silica surface modifying materials that suppress nonspecific adsorption of proteins.

Claims (5)

A methoxy oligoethylene glycol-silane compound represented by the following chemical formula (1);
(Wherein X _{1 to} X ₃ each independently represent a halogen, an alkoxy group having 1 to 3 carbon atoms, or an alkyl group having 1 to 3 carbon atoms, provided that at least one of X _{1 to} X ₃ Is a halogen or an alkoxy group having 1 to 3 carbon atoms, and a is an integer of 1 to 10.
R _{is, - (CH 2) m -} (OCH 2 CH 2) n - represents a. m is an integer of 2 to 10, and n is an integer of 0 to 5. ) It is a manufacturing method of the methoxy oligo ethylene glycol-silane compound (Chemical formula 1) of Claim 1, Comprising: It represents with following (Chemical formula 2).
(Wherein, a is the same as defined in (Chemical Formula 1), Y represents a carboxylic acid active group), and is represented by the following (Chemical Formula 3):
(Wherein, X _{1 to} X ₃ and R are the same as defined in (Chemical Formula 1)). Methoxy oligoethylene glycol of claim 1 - a thin film made of a silane compound, a thin film that modifying at least part of the device or its substrate surface. A device or a substrate thereof, wherein at least one surface is modified with a thin film comprising the methoxy oligoethylene glycol-silane compound according to claim 1.   The device according to claim 4 or a substrate thereof, wherein the device is a waveguide mode sensor, and the substrate is a biosensing element used in the device.