Shell-encoded Au nanoparticles with tunable electroactivity for specific dual disease biomarkers detection

- Shell-encoded Au NPs (Au@Cu2O and Au@Ag core-shell NPs) are fabricated.
- Shell-encoded Au NPs give rise to shell species-dominated DPV peak potentials.
- Shell-encoded Au NPs exhibit shell thickness-tunable amplified peak currents.
- Shell-encoded Au NPs are applied for the sensitive dual screening of CEA and AFP.
- The LODs are calculated to be 1.8 pg/mL for CEA and 0.3 pg/mL for AFP.

The exploration of electroactive labelling with tailorable and strong differential pulse voltammetry (DPV) responses is of great importance in accurate and sensitive screening of a panel of biomarkers related to cancer. Herein, shell-encoded gold nanoparticles (Au NPs) are fabricated and give rise to shell species-dominated DPV peak potentials. Two independent DPV peaks appear at −0.08 V for Au@Cu2O core-shell NPs and 0.26 V for Au@Ag core-shell NPs. Shell-encoded Au NPs drastically exhibit shell thickness-tunable amplified peak currents. The non-interfering and amplified DPV responses enable shell-encoded Au NPs to be an alternative electrochemical signal amplifier for dual screening of carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP). The limits of detection (LODs) are calculated to be 1.8 pg/mL for CEA and 0.3 pg/mL for AFP. In comparison to the parallel single-analyte assays, shell-encoded Au NPs engineered electrochemical aptasensors offer multiplexing capability and show significant prospects in biomedical research and early diagnosis of diseases.