Regenerable photonic aptasensor for detection of bacterial spores with stacks of GaAs/AlGaAs nanoheterostructures

Abstract

The reusability of biosensors is crucial for environmental monitoring and advancing laboratory operations. This study presents the concept of a regenerable aptasensor based on digital photocorrosion (DIP) of a GaAs/AlGaAs biochip composed of GaAs (12 nm) and AlGaAs (10 nm) nanolayers. We demonstrate the specific immobilization of Bacillus thuringiensis spp. kurstaki spores using thiolated aptamer-spore hybrids interacting with surface of GaAs atoms. After completing a biosensing run utilizing the first pair of GaAs-AlGaAs nanolayers, regeneration was achieved by exposing the aptasensor to 3X PBS, which stripped the spores and prepared the same biochip for a consecutive biosensing run with the second pair of nanolayers. We explore the conditions necessary for sustainable DIP of biochips with multiple GaAs-AlGaAs nanolayer pairs, essential for numerous biosensing cycles. Our findings provide strong evidence for operating a cost-effective aptasensor suitable for quasi-autonomous operation in out-of-laboratory environments.