We developed a biosensing technology based on a model biological membrane and a nanometric gap structure. The model biological membrane was composed of polymeric and fluid lipid bilayers. The polymeric lipid bilayer was attached with a silicone elastomer (polydimethylsiloxane: PDMS) sheet using silica nanoparticles as the adhesion layer, creating a nanometric gap junction between the fluid bilayer and PDMS (nanogap-junction). Thickness of the nanogap-junction was controlled by the size of silica nanoparticles. Since only molecular species that specifically bind onto the fluid bilayer can penetrate into the nanogap-junction, the selectivity and sensitivity of biosensing in the nanogap-junction is expected to increase as the gap thickness decreases. This hypothesis was verified by using a mixture of model target protein (cholera toxin: CTB) and coexisting protein (bovine serum albumin: BSA). CTB was selectively transported into the gap owing to its specific binding to a glycolipid (G<sub>M1</sub>) in the fluid bilayer and detected in the nanogap-junction with an elevated signal-to-noise-ratio. The signal-to-noise ratio was more significantly enhanced in a thinner gap, corroborating the theoretical prediction. Silica nanoparticles proved to be an excellent material for the adhesion layer due to their mono-disperse size and mechanical stability. The nanogap-junction offers a platform for biosensing applications for which detection of specific target molecules in the presence of coexisting molecules is important.

Nanometric gap structure for selective biosensing created with patterned lipid bilayer, silicone elastomer, and silica nanoparticles

255th National Meeting (2018)

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