Fouling-Proof Nanopore for Detecting Caspase-3 in Complex Biological Fluids.

Caspase-3 plays a critical role in apoptosis and has been regarded as a key marker in apoptosis-related disease diagnosis and therapy. However, the Caspase-3 detection in complex biological environments remains challenging due to the existence of various interferences. To solve this challenge, an antifouling nanopore biosensor is constructed by integrating distearoylphosphatidyl ethanolamine-poly(ethylene glycol) (DSPE-PEG) and a Caspase-3-targeted peptide in a single glass nanopore, and it has been successfully used for the detection and analysis of Caspase-3 protease in complex biological environments. Contact angle, electrochemical, and confocal imaging characterizations confirm the good antifouling ability of the biosensor. The sensing performance of the biosensor was characterized by the change in the nanopore's rectified ionic current. The results indicated that the antifouling biosensor has a good detection performance for Caspase-3, with a detection limit of 0.46 ng/mL, and excellent selectivity against interfering proteins.