Biomolecular binding dynamics in sensors based on metallic photonic crystals

We investigated the evolution dynamics of sensor signal for the binding of the bovine serum albumin (BSA) molecules to the metallic photonic crystals (MPCs). Measurements on the BSA/phosphate solution indicate a sensitivity as high as 1 ng/ml of the MPC sensor device. The experimental results show a highly nonlinear relationship between the amplitude of the sensor signal and the BSA concentration, where the binding rate increases with the increase in the concentration of the BSA/phosphate solution. Furthermore, there exists an upper limit of the concentration of the BSA/phosphate solution as low as 1 mg/ml for sensor applications, which is determined such that no refractive index change is introduced due to the increase in the solution concentration.