Towards an early diagnosis of HIV infection: An electrochemical approach for detection of HIV-1 reverse transcriptase enzyme

Oriented for the rapid diagnosis of HIV infection, highly sensitive and facile electrochemical assays for HIV-1 reverse transcriptase (HIV1-RT) are presented in this article. A non-labeled and a labeled assay format were based on the formation of self-assembled monolayers (SAMs) of either lipoic acid active ester or a newly synthesized ferrocene (Fc)-labeled cystamine derivative on electrode surfaces, respectively. A short RT-specific peptide, VEAIIRILQQLLFIH, was covalently attached to the surface of the formed SAMs. Electrochemical impedance spectroscopy (EIS) allowed a sensitive interrogation of RT in the non-labeled assay format. Furthermore, square wave voltammetry (SWV) offered a two-dimensional measurement of RT based on the anodic shift and reduction of current density of the Fc redox signal upon binding of RT to its specific peptide. These techniques allowed a linear quantification of the target RT in the range of 75 to 750 pg mL^-1, with a limit of detection of 50 pg mL^-1. Furthermore, the developed biosensors showed a good specificity and allowed a proper discrimination between RT and other HIV enzymes.