Aptamer-functionalized nanoporous gold film for high-performance direct electrochemical detection of bisphenol A in human serum

• NPGF exhibits excellent catalytic activity towards the redox reaction of BPA.
• The perfect combination of NPGF with aptamer ensures high sensitivity and selectivity.
• The detection limit is determined to be 0.056 ± 0.004 nM BPA.
• The detection limit is 15-fold lower than gold nanoparticle-based sensor.
• The sensor was successfully applied to detect BPA in human serum samples.

In the present work, a highly sensitive and selective biosensor based on aptamer-functionalized nanoporous gold film (NPGF) was successfully developed for direct electrochemical detection of bisphenol A (BPA). NPGF was prepared by dealloying Ag from Au/Ag alloy leaf in concentrated nitric acid. The obtained NPGF was attached onto glassy carbon electrode and then was functionalized with BPA-specific aptamer via the formation of AuS bond. The fabrication of the sensor was characterized by scanning electron microscopy and X-ray photoelectron spectroscopy. NPGF exhibited excellent electrocatalytic activity towards the redox reaction of BPA, which ensured high sensitivity of the sensor. The aptamer-captured BPA showed a pair of redox peaks around 0.35/0.28 V (vs. Ag/AgCl). The experimental parameters in terms of aptamer concentration, reaction time, pH, and temperature were optimized. The calibration plot showed a linear range from 0.1 nM to 100 nM BPA with a remarkable detection limit of 0.056 ± 0.004 nM BPA. Particularly, the successful application of the developed sensor for the detection of BPA in human serum samples suggests its promising potential for clinical diagnosis.

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