Characterizing the thermal ablation of cells for silicon biosensors

Abstract

Being able to restore the surface of biosensors to their initial material-free state after immobilization of the biological target can facilitate biosensor development and reduce measurement costs. Thermal ablation has been recently proposed as a new method to conveniently accomplish this using high temperature heating with a hot plate. Key variables related to chip heating are characterized to optimize the effectiveness of thermal ablation. Testing was performed using Poly-L- Lysine-functionalized silicon-on-insulator chips and E. coli. An analysis based on image processing demonstrates that the maximum temperature reached by the chip and the length of time the chip is held at the maximum temperature significantly affect cell removal, while the heat rate at which the chip goes from room temperature to the maximum temperature does not affect cell removal. It was found that nearly all cells can be removed by heating the chip at 425°C for 10 s or by heating the chip at 375°C for 100 s.