[16p-F205-1~18] 12.7 Biomedical Engineering and Biochips

[16p-F205-10] Optical interferometric surface stress biosensor using elastomer nanosheet

〇Reina Teramoto¹, Toshinori Fujie^2,3, Nobutaka Sato², Shinji Takeoka², Kazuaki Sawada¹, Kazuhiro Takahashi^1,3 (1.Toyohashi Tech., 2.Waseda Univ., 3.JST PRESTO)

Keywords:biosensor

MEMS surface stress sensor can detect various biomarkers in a label-free manner by transducing from stress change due to molecular adsorption to deformation of the microstructure. We have previously developed a MEMS optical interferometric surface stress sensor which employs organic materials for sensing area. For the surface stress sensing, a low Young’s modulus material provides high stress sensitivity. In particular, an elastomer is one of the most promising material for the surface stress sensor because of low Young’s modulus of 1-100 MPa. We have also developed a freestanding elastomer nanosheet using a polystyrene-polybutadiene-polystyrene triblock copolymer (SBS) with Young’s modulus of 40 MPa. In this paper, we developed a MEMS surface stress sensor based on the elastomer nanosheet for a suspended membrane in order to improve the stress sensitivity. To form a diaphragm structure above a nanocavity, shallow trenches on a silicon substrate were prepared. For improvement of adhesion, a silane coupling agent was coated on the silicon wafer, followed by transferring nanosheet at room temperature. We measured reflection spectrum to evaluate air gap length, which was good agreement with a fitting curve of 2.46 mm gap. The spectrum peak redshifted in solution with anti-bovine serum albumin antibody, which suggested that the membrane was deformed in upper direction caused by molecular adsorption.