Conversion of protein net charge via chemical modification for highly sensitive prion detection using field effect transistor (FET) biosensor

A robust and applicable strategy of signal amplification for field effect transistor (FET) biosensor is of scientifically and technologically importance to detect wide range of target molecules, particularly for the molecules of low charge density, and to configure highly sensitive analysis. In this communication, we demonstrate a simple technique to modify the net charge of target protein based on the concept of protein conjugation for the detection of prion, which is infectious and transmissible protein in neurodegenerative disorders. The increases of prion net charge after chemical modification generate signal amplification and have remarkably enhanced the sensitivity of FET biosensor below than femtomolar (fM) level. Thus, we suggest that such strategy is promising technique for achieving a highly sensitive detection at very low concentration that is useful for early determination of protein biomarkers.