Preparation of a sensor substrate using functionalized mesoporous silica on a gold film for surface plasmon resonance (SPR) spectroscopy

Abstract

The use of surface plasmon resonance (SPR) spectroscopy has been applied to a wide variety of fields such as biosensors and surface analysis instruments. In general, a SPR substrate is prepared using self-assembled monolayer (SAM) method of organic molecules as receptor for the target on a layer of gold or silver. However, mesoporous inorganic materials such as SBA-15 have benefits as sensor substrate for SPR. Mesoporous silica has a large surface area which receptor molecule can be attached and has a rigid body which has an excellent stability in the extreme condition compared to organic sensing layer. We prepared an organic modified mesoporous silica and successfully immobilized it on a gold surface, in an attempt to use as a substrate for SPR spectroscopy. For the comparison of sensitivity of prepared substrate, Pt 2+ detection was selected as a model system. Substrate prepared in this study exhibited the capability of selective sensing for Pt 2+ ions.

Mesoporous Silicate Materials in Sensing

“…These materials did not rely on dye incorporation but instead used a metal chelating functional group together with spectrophotometric quantification of Cu 2+ (blue) or Cr 6+ (yellow). Mercaptopropyltriethoxysilane functionalized SBA-15 has been used to enhance surface plasmon resonance signals on a gold substrate [67, 68]. Hybrid thiol-SBA-15 particles were deposited on Au, and the remainder of the Au surface was functionalized with 1,6-hexanedithiol (HDT).…”

Functionalized silica nanostructures for biosensing applications

“…These porous surfaces can be applied to the SPR substrate by spin coating or electrostatic self-assembly (ESA). Porous surfaces increase the surface area, providing the ability to incorporate receptor sites for biochemical reactions with their corresponding analytes [44]. Porous surfaces have been applied to silica-based films, but often these films are thicker than the SPR evanescence wave and cannot be used for SPR sensory studies.…”

“…As for the sensitivity of the porous surfaces, the work by Oh et al [44] demonstrated an increase in sensitivity compared to nonporous surfaces. Oh and colleagues used an inorganic mesoporous silica (SBA-15) suspension treated with (3mercaptopropyl) trimethoxysilane (MPTMS) to attach thiol groups.…”

“…Oh and colleagues used an inorganic mesoporous silica (SBA-15) suspension treated with (3mercaptopropyl) trimethoxysilane (MPTMS) to attach thiol groups. The authors attached the grafted mesoporous silica (MP-SBA) to a gold substrate using self-assembly of the gold-thiol interaction [44]. For comparison, another substrate was prepared using 1,6-hexanedithiol to generate a nonporous surface.…”

“…Before and after SPR angular shift during the detection of 10 -3 M solution of Pt 2+ using the MP-SBA porous surface. Nonporous surface angular shift was 0.25 degrees and porous was 1.3 degrees [44] (reprinted with permission from Springer).…”