The design of paper-based electroanalytical microfluidic device coupled with post-synthesized molecularly imprinted polymers (rGO/Au@Ag2S/PANI/polyacrylamide) for the detection of streptomycin

Abstract

A highly sensitive three-electrode paper-based microfluidic device has been developed for determinate of streptomycin. Ag/GQD/chitosan nano ink was used to construct reference and counter electrodes and Au@Ag₂S/GQD/chitosan nano ink was used to construct working electrode. rGO/Au@Ag₂S/anline nano-sheets were encapsulated with acrylamide as a functional monomer to create novel nano-sized molecular imprinted polymer (MIP) and was used for the modification of electrode working.

Paper substrate was modified for forming a hydrophobic region around the hydrophilic region on the filter paper and were suitable for the evaluation of target molecules in aqueous environment. All steps of making the MIP and non-imprinted polymer (NIP) sensors are illustrated by FE-SEM, Energy-dispersive X-ray spectroscopy (EDS), and FT-IR. CV and DPV techniques were applied for the measurement of the streptomycin. The fabricated device showed high sensitivity toward streptomycin, which was due to synergistic effects between catalytic properties, electrical conductivity of rGO/Au@Ag₂S/anline /Polyacrylamide, and considerably increased numbers of imprinted sites. Using these techniques, streptomycin was determined in the linear range of 1pM to 1 μM with a limit of detection of 0.9 × 10⁻¹² M (Ip (μA) = -2.075x + 31.575, R²= 0.9983). The device provided good cyclic stability (RSD < 0.05), high reproducibility and selectivity (RSD < 0.05 obtained from five calibration plots) with a good repeatability (for both milk and serum samples, RSD < 0.05). Finally, it should be noted that this device showed a good analytical performance for the detection of streptomycin in milk and serum samples.