Metal Mesh Device Sensor Immobilized with a Trimethoxysilane-Containing Glycopolymer for Label-Free Detection of Proteins and Bacteria

Abstract

Biosensors for the detection of proteins and bacteria have been developed using glycopolymer-immobilized metal mesh devices. The trimethoxysilane-containing glycopolymer was immobilized onto a metal mesh device using the silane coupling reaction. The surface shape and transmittance properties of the original metal mesh device were maintained following the immobilization of the glycopolymer. The mannose-binding protein (concanavalin A) could be detected at concentrations in the range of 10(-9) to 10(-6) mol L(-1) using the glycopolymer-immobilized metal mesh device sensor, whereas another protein (bovine serum albumin) was not detected. A detection limit of 1 ng mm(-2) was achieved for the amount of adsorbed concanavalin A. The glycopolymer-immobilized metal mesh device sensor could also detect bacteria as well as protein. The mannose-binding strain of Escherichia coli was specifically detected by the glycopolymer-immobilized metal mesh device sensor. The glycopolymer-immobilized metal mesh device could therefore be used as a label-free biosensor showing high levels of selectivity and sensitivity toward proteins and bacteria.

Quantitative Measurement of Protein Using Metal Mesh Device

“…The dip in the spectra were specific phenomena in MMD, which have been reported by our group [13][14][15] and other groups. 8,9 The dip was the result of fano-like interference effect between the terahertz light transmitted directly and obliquely through MMD.…”

“…In the experiments, protein adsorption caused the dip frequency shift. [13][14][15] The magnetic permeability of the organic substances is usually less than 1. The dip frequency shift from the inductance change can be ignored due to the small magnetic permeability.…”

“…In 2011, we reported the sensing principles of MMD in the sub-millimeter range, 12 and the possibility of protein sensing adsorbed onto the MMD by the transmittance property in the terahertz (infrared) region. [13][14][15] The MMD was manufactured with the electroforming method, which enables the fabrication of the devices of various structures, sizes, and transmittance properties of arbitrary frequency (wavelength). Therefore, it is possible to utilize the specific MMD corresponding to the target substances.…”

Label-free Detection of Antigen Protein Using a Metal Mesh Device Surface-modified by an Antibody

“…Based on this phenomenon, MMD sensors, which detect the quantity of substance from the shift in the spectrum, have been developed. [4][5][6][7][8][9][10][11][12] Metal species for manufacturing are not limited, because MMDs made from various metals have extraordinary transmittance. MMDs offer high-throughput, compared with QCM and SPR, and can be used in screening and initial diagnosis.…”

“…8 The sensitivity, which is affected by changes in the complex refractive index, decreases exponentially with leaving from the MMD surface. 8,9,12 Detection by the sensing system, in which biomolecular targets are directly adsorbed on the MMD surface, is therefore high. MMD surfaces have been modified by biotin and saccharide to achieve the direct adsorption of biomolecular targets, in which 100 THzMMDs with small periodic sizes were used.…”