A novel leaky surface acoustic wave biosensor for detection of PKA activity in cell lysates based on peptide biomineralized metal nanoclusters

While protein kinases play a pivotal role in various fundamental biological processes, their overexpression can lead to several human diseases. Herein, we propose a highly sensitive leaky surface acoustic wave (LSAW) biosensor for detecting protein kinase A (PKA) activity based on peptide-templated copper nanoclusters for signal enhancement. The substrate peptide P1, specific for PKA, was self-assembled on a gold-coated SAW surface. In the presence of PKA and adenosine-5 '-triphosphate (ATP), the serine within P1 was phosphorylated. Another peptide, P2, which contained a cluster formation sequence CCY, was used to prepare the peptide-templated copper nanoclusters (P2-CuNCs) and a guanidine group within arginine residue was used to iden-tify the phosphorylation site specifically. The P2-CuNCs were captured on phosphorylated peptide P1 through covalent-like the interaction of guanidine-phosphate, which resulted in amplified SAW signals. Under the optimal conditions, the SAW sensor showed a quantitative readout to PKA concentration in the range 0-50 U/ mL with a detection limit of 0.02 U/mL for PKA. In addition, the biosensor was used to screen protein kinase inhibitors and detect protein kinase activity in drug-stimulated complex cell lysates, showing great potential use in drug discovery and disease diagnosis.

Automated summary

A highly sensitive leaky surface acoustic wave (LSAW) biosensor was proposed for detecting protein kinase A (PKA) activity. The biosensor utilized peptide-templated copper nanoclusters for signal enhancement. The biosensor showed great potential use in drug discovery and disease diagnosis by screening protein kinase inhibitors and detecting protein kinase activity in drug-stimulated complex cell lysates.