Incorporating Peptide Aptamers into Resistive Pulse Sensing

The use of nanocarriers within resistive pulse sensing, RPS, aids the detection and quantification of analytes. In the absence of convection, the signal strength and frequency can dependent upon the electrophoretic mobility of the nanocarrier/ analyte. Here we have developed a simple strategy to incorporate peptide aptamers onto RPS assays with enhanced electrophoretic signals. Using a hybrid DNA-Peptide nanocarrier an existing peptide was incorporated into a rapid assay without having to engineer or modify the peptide sequence. The surface of a nanocarrier is coated with a mixture of peptide aptamers and a nonbinding DNA. The binding of the target to the peptide creates an “analyte corona” which shields the phosphate groups of the underlying DNA. This results in a change in electrophoretic mobility of the nanocarrier. The signal is concentration dependent and is illustrated using a peptide to a key biomarker of infection, C-Reactive Protein, CRP. As a comparison we also show the binding of the CRP to a DNA aptamer. This universal approach can be easily adapted to other peptides without the peptide itself to undergo any chemical modifications opening new opportunities and applications in RPS strategies.