Analysis of drug–protein interaction in bio-inspired microwells

Abstract

The study of binding of drug with protein is an important process in determining the activity and consequences of the drug. However, the current screening methods to investigate the drug–protein interaction are still pervaded with some disadvantages such as large requirement of sample volume and the need of expensive instrumentation. Here, we present a proof of concept for a method to study the interaction of different kinds of drugs with protein on a microwell array, to enable the understanding of pharmacokinetics in a fast and facile manner. To this end, we demonstrated the applicability of present method by analysing the interaction of fluorescently labelled bovine serum albumin (FITC-BSA) with sulphanilamide (SMO) and sulfamethoxazole (SMZ) drugs on lotus leaf-based microwells. The quenching mechanism of FITC-BSA in the presence of SMO and SMZ is visualized through time-lapse fluorescence imaging for the first time in femto-litre sized microwells. The binding parameters extracted from the present method are found to be in good agreement with the fluorescent spectroscopy measurements. The interaction between protein and drugs was further corroborated by molecular docking analysis and FT-IR technique. Finally, the bio-inspired microwell array was integrated into a magnetic digital microfluidic device to facilitate investigation of drug–protein interaction in power-free and cost-effective manner. A substantial decrease in sample volume and relatively short processing times when compared to other bulk methods makes the present method attractive. The results presented here therefore open up the possibility of rapid measurement of binding parameters in protein–ligand interaction studies in low-resource environments.