Electrodeposition of Silver Amalgam Particles on Screen-Printed Silver Electrodes in Voltammetric Detection of 4-Nitrophenol and Artificial Nucleosides dTPT3 and d5SICS

Electrodeposition of silver amalgam particles (AgAPs) on various substrates offers perspective tool in development of novel electrochemical detection system applicable even in direct bioelectrochemistry of nucleic acids or proteins. Herein, a double pulse chronoamperometric deposition of AgAPs on in-house fabricated screen-printed silver electrodes (SPAgE) has been optimized using voltammetric signal of model electrochemically reducible organic nitro-compound, 4-nitrophenol, and scanning electron microscopy with energy dispersive X-ray spectrometer. This compact sensor including graphite counter and Ag|AgCl pseudo-reference electrode was design for highly effective analysis of electrochemically reducible compounds in 96-well plate with about 150-µl sample volume per well. The SPAgE-AgAP offers detection of 4-NP down to 5 µmol.l⁻¹ using cyclic voltammetry in acetate buffer pH 5.0. Advantageously, differential pulse voltammetry at SPAgE-AgAP allows highly sensitive detection system of unnatural nucleosides dTPT3 and d5SICS, which successfully expanded genetic alphabet of recently studied semi-synthetic organism, with limits of detection 0.1 pg.µl⁻¹ in 0.05 mol.l⁻¹ hydrochloric acid. Moreover, these artificial nucleosides are detectable in the mixture with natural nucleosides up to weight ratio 1 : 15 000. SPAgE-AgAP may be potentially utilized in simple, fast and sensitive electrochemical detection of organic nitro compounds and free or in DNA harbored dTPT3 and/or d5SICS, what may contribute in successful research and development of semi-synthetic organism perspective in chemical and synthetic biology.