Multi-sample acoustic biosensing microsystem for protein interaction analysis

The current work describes a novel setup for multi-sample biomolecular analysis. It is based on the assembly of a dual acoustic device chip with a four-channel microfluidic module, forming an array of eight available domains for experiments. Initially, multiple detection was demonstrated via the specific interaction of neutravidin with four different biotinylated proteins, namely protein G, protein A, bovine serum albumin, and immunoglobulin G; results revealed a reproducibility between the microchannel domains better than 90%. Real-time analysis of the binding interactions was used to calculate the affinity and kinetic constants of the four biotinylated molecules binding to surface-immobilized neutravidin; this was the first time that this information was derived using a biosensing device and four biotinylated molecules. Interestingly, all calculated kinetic and affinity constants resemble those typical of antibody-antigen interactions, although the investigated specific binding was of avidin–biotin nature. Finally, under device pre-functionalization conditions, it was possible to probe eight interactions all together, exploiting the full capacity of the microsystem and reducing significantly the analysis time, contrary to the use of the standard acoustic device configuration. The outcome of this full-scale validation opens the way for the integrated acoustic platform to be implemented in even higher throughput detection for future diagnostic/biomedical applications, as well as in fundamental research studies regarding biomolecular interaction investigation and characterization.