NiFe-LDH@MXene nanocomposite with demonstrated biocompatibility for selective monitoring of Sunset Yellow.

Abstract

Monitoring trace levels of Sunset Yellow (SSY) in processed foods demands electrode materials that combine high electrochemical activity with biological safety. Here, NiFe-layered double hydroxide nanosheets were grown directly on delaminated Ti3C2Tx MXene through a one-step hydrothermal route, yielding a sheet-on-sheet heterostructure in which the LDH component supplies redox-active Ni/Fe sites while the MXene backbone ensures rapid electron transport. Cytotoxicity tests on RAW 264.7 macrophages, hemolysis assays, and antibacterial screening confirmed that the composite poses no appreciable biological risk at the working concentrations, satisfying a key prerequisite for food-contact sensing materials. When deposited on a glassy carbon electrode, the nanocomposite achieved a detection limit of 4.1 nM for SSY by square wave voltammetry over the range 0.05-40 μM (R2 = 0.996), with less than 11% signal variation in the presence of a 10-fold excess of common interferents. Distinct oxidation potentials further enabled discrimination between SSY and the structurally related dye tartrazine. Recovery tests in commercial orange, grape, and apple juice samples returned 97-104%, indicating minimal matrix interference. These results position NiFe-LDH@MXene as a biologically benign sensing platform suitable for routine food-safety screening.