Temperature effects on liquid crystal-based tunable biosensors

Abstract

A novel tunable surface plasmon resonance biosensor based on liquid crystal is demonstrated. The liquid crystal surface plasmon resonance (LC-SPR) biosensor response to temperature was studied for four usual 5CB, 5PCH, E7, and E44 nematic liquid crystals by modeling and simulation. The results indicated that after including the analyte, the change of liquid crystal birefringence occurs differently at various temperatures. Consequently, the variation of biological agents can be detected by the shift of the surface plasmon resonance angle. The results show that the temperature variation of maximum sensitivity occurs for the homogeneous alignment more than the homeotropic alignment. But the maximum sensitivity increasing rate in homeotropic alignment, is approximately two times greater than homogeneous alignment, in the near of transition temperatures. In the nematic to isotropic transition region, the maximum sensitivity increasing rate is 3.05 Deg/RIU°C for 5CB and 1.03 Deg/RIU°C for 5PCH based biosensors for homeotropic alignment. The sensitivity of 5CB and 5PCH based biosensors is greater than E7 and E44 liquid crystals.