Dopamine‐loaded Liposomes‐amplified Electrochemical Immunoassay Based on MXene (Ti3C2)−AuNPs

Abstract A simple and novel electrochemical immunoassay based on MXene (Ti 3 C 2 )−Au nanoparticles (AuNPs) was designed for sensitive screening of a disease‐related biomarker, prostate‐specific antigen (PSA), by using dopamine‐loaded liposomes (DLL) for signal amplification. The system involves two parts, namely, sandwich‐type immunoreaction to capture DLL and electrochemical measurement of dopamine. The target PSA can cause a specific antigen‐antibody reaction and DLL are enriched in the enzyme‐labeled pores. After Triton X‐100 is injected into the detection cell, the carried DLL was quickly cracked to release dopamine wrapped in the cavity. A nanocomposite consisting of MXene (Ti 3 C 2 ) support to immobilize Au nanoparticles (Ti 3 C 2 −Au) was utilized to modify a glassy carbon electrode, which gives a strongly enhanced differential pulse voltammetric (DPV) signals for dopamine. In this case, the change of DPV signal depends on the amount of dopamine released by liposomes, which is further positively correlated with the concentration of the analyte PSA. Combining the of MXene (Ti 3 C 2 )−AuNPs nanomaterials (large specific surface area, excellent electrical conductivity, and good electrocatalytic properties) with the liposome signal amplification strategy, the electrochemical immunoassay exhibited excellent performance toward PSA determination with a broad linear range of 1 pg/mL to 50 ng/mL and limit of detection down to 0.31 pg/mL (S/N=3) under the optimized testing conditions. High specificity for PSA over other disease‐related biomarkers and acceptable nanocomposite/electrode stability were acquired. The excellent analytical performance shows that the current strategy provides an effective detection platform for clinical sample analysis.