Gold nanoparticles-doped MXene heterostructure for ultrasensitive electrochemical detection of fumonisin B1 and ampicillin.

Early transition metal carbides (MXene) hybridized by precious metals open a door for innovative electrochemical biosensing device design. Herein, we present a facile one-pot synthesis of gold nanoparticles (AuNPs)-doped two-dimensional (2D) titanium carbide MXene nanoflakes (TiCT/Au). TiCT MXene exhibits high electrical conductivity and yields synergistic signal amplification in conjunction with AuNPs leading to excellent electrochemical performance. Thus TiCT/Au hybrid nanostructure can be used as an electrode platform for the electrochemical analysis of various targets. We used screen-printed electrodes modified with the TiCT/Au electrode and functionalized with different biorecognition elements to detect and quantify an antibiotic, ampicillin (AMP), and a mycotoxin, fumonisin B1 (FB1). The ultralow limits of detection of 2.284 pM and 1.617 pg.mL, which we achieved respectively for AMP and FB1 are far lower than their corresponding maximum residue limits of 2.8 nM in milk and 2 to 4 mg kg in corn products for human consumption set by the United States Food and Drug Administration. Additionally, the linear range of detection and quantification of AMP and FB1 were, respectively, 10 pM to 500 nM and 10 pg mL to 1 µg mL. The unique structure and excellent electrochemical performance of TiCT/Au nanocomposite suggest that it is highly suitable for anchoring biorecognition entities such as antibodies and oligonucleotides for monitoring various deleterious contaminants in agri-food products.