JP-7855067-B2 - Coated metal substrate and method for producing the same, composite containing the coated metal substrate, and polymer for producing the coated metal substrate

Inventors

• 小松 由枝
• 北脇 文久

Assignees

• ＰＨＣホールディングス株式会社

Dates

Publication Date

20260507

Application Date

20230517

Priority Date

20220531

Claims (7)

1. It has a hydrophilic group at the end of its side chain, which is bonded via a disulfide group. The hydrophilic group includes a polar group and/or an electrostatic group, The polar group comprises at least one selected from the group consisting of a carboxyl group, a hydroxyl group, an amino group, a sulfonyl group, a phosphate group, and an alkylene oxide group. The charged group comprises at least one selected from the group consisting of a charged polar group and a zwitterionic group, and the zwitterionic group comprises at least one selected from the group consisting of a phosphorylcholine group and a betaine group. A polymer having an amide bond in its main chain skeleton .
2. The polymer further contains positively charged groups in its side chains, The aforementioned side chain does not have a disulfide bond. The polymer according to claim 1, wherein the positively charged group is at least one selected from the group consisting of a primary ammonium group, a secondary ammonium group, a tertiary ammonium group, a quaternary ammonium group, and a guanidyl group (-NHC (= NH2 + ) NH2 ).
3. The polymer further contains hydrophobic groups in its side chains, The aforementioned side chain does not have a disulfide bond. The polymer according to claim 1, wherein the hydrophobic group is at least one selected from the group consisting of aromatic cyclic groups, aliphatic cyclic groups, and aliphatic chain groups.
4. The polymer has a main chain skeleton that is derived from one or more amino acids, The polymer according to claim 1, wherein the amino acid comprises at least one selected from the group consisting of lysine, histidine, arginine, glutamic acid, aspartic acid, glutamine, asparagine, serine, and threonine.
5. The polymer according to claim 1, wherein the main chain skeleton of the polymer contains a biocompatible polymer as a block polymer.
6. A method for producing a coated metal substrate, comprising the step of bringing the polymer described in claim 1 into contact with the surface of a metal substrate, thereby bonding the hydrophilic groups to the surface of the metal substrate, and forming a polymer film on the surface of the metal substrate.
7. The method for producing a coated metal substrate according to claim 6 , wherein in the side chain, the length of the first side chain from the disulfide group to the hydrophilic group is longer than the length of the second side chain from the disulfide group to the main chain of the polymer.

Description

This invention relates to a coated metal substrate, a method for producing the same, a composite containing the coated metal substrate, and a polymer for producing the coated metal substrate. A biosensor detects a specific test substance by specifically reacting it with a specific binding substance to form a complex, and then detecting the test substance based on the signal resulting from the specific binding in the complex. In plasmon-induced fluorescence analysis, the complex comprises, for example, a test substance, a specific binding substance, a fluorescent substance, and metal particles. When excitation light is shone on the complex, surface plasmon resonance is induced in the metal particles within the complex, creating a near-field near the surface of the metal particles. This near-field increases the fluorescence intensity of the fluorescent substance. When analyzing a test substance by specifically reacting it with a specific uniquely binding substance to form a complex, there is a problem of deterioration of the signal-to-noise ratio (S/N ratio) due to nonspecific adsorption to the metal particle surface. This is also true for plasmon-excited fluorescence analysis using metal particles, where nonspecific adsorption to the metal particle surface may worsen the S/N ratio. For example, as described in Patent Document 1, a polymer film is formed by attaching the ends of one-dimensional polymers (polymer chains) to the surface of metal nanoparticles. By arranging multiple polymer chains on the metal substrate surface so as to be approximately perpendicular to the surface of the metal substrate, a polymer film is formed in which the polymer chains are arranged in a brush-like manner. International Publication No. 2001/086301 Figure 1 is a schematic cross-sectional view showing a coated metal substrate according to the second embodiment ((a) nanoparticles and (b) coated metal thin film).Figure 2 is an enlarged schematic diagram of section A in Figure 1(a).Figure 3 is a schematic cross-sectional view showing the composite according to the third embodiment.Figure 4 is a schematic diagram showing a measuring device for detecting a test substance using the composite according to the third embodiment.Figure 5 is a schematic cross-sectional view showing the composite according to the fourth embodiment.Figure 6 shows the absorption spectra at each step of polymer synthesis.Figure 7 shows the reaction in the polymer film formation method of Example 1.Figure 8 is an SEM image of the polymer-coated hydrophilic group-labeled silver nanoparticles of Example 1.Figure 9 shows the distribution of the scattered light intensity ratio to zeta potential for polymer-coated hydrophilic group-labeled silver nanoparticles in Example 1.Figure 10 shows the distribution of the scattered light intensity ratio to particle size for polymer-coated hydrophilic group-labeled silver nanoparticles of Example 1.Figure 11 shows an SEM image of the polymer-coated hydrophilic group-labeled silver nanoparticles of Example 2.Figure 12 shows the distribution of the scattered light intensity ratio to zeta potential for polymer-coated hydrophilic group-labeled silver nanoparticles in Example 2. The following describes in detail embodiments of the present invention, including nanoparticles, their manufacturing method, composites, and measuring devices, with reference to the illustrated embodiments. Note that the drawings include schematic representations and may not reflect actual dimensions or proportions. Numerical ranges referred to herein are intended to include the lower and upper limits themselves, unless otherwise specified by terms such as "less than," "greater than," and "less than." For example, if we consider a numerical range of 1 nm to 50 nm, unless otherwise specified, this range is interpreted as including the lower limit "1 nm" and the upper limit "50 nm." In this specification, "metal substrate" means a substrate that is substantially composed of metal and contains metal thin films (also referred to as metal plates or metal films) and metal nanoparticles. Metal nanoparticles and metal thin films differ mainly in shape. In this specification, when a subject member is said to be substantially composed of a specific material or to consist of a specific material, it means that the subject member contains the specific material in proportions of 95% or more by mass, 97% or more by mass, 99% or more by mass, or 100% by mass. For example, when a metal substrate is said to be substantially composed of metal, it means that the metal substrate contains metal in proportions of 95% or more by mass, 97% or more by mass, 99% or more by mass, or 100% by mass. In this specification, "metal nanoparticles" means particles substantially composed of metal, having a size on the order of nanometers (e.g., several nm to 100 nm), and having a spherical or nearly spherical shape. "Metal nanoparticles" induce localized surface plasmon resonance with other