Hybridizing Ti3C2Tx Layers with Layered Double Hydroxide Nanosheets at the Molecular Level: A Smart Electrode Material for H2O2 Monitoring in Cancer Cells

Vertically stacked artificial 2D superlattice hybrids fabricated through molecular-level hybridization in a controlled fashion play a vital role in scientific and technological fields, but developing an alternate assembly of 2D atomic layers with strong electrostatic interactions could be much more challenging. In this study, we have constructed an alternately stacked self-assembled superlattice composite through integration of CuMgAl layered double hydroxide (LDH) nanosheets having positive charge with negatively charged Ti3C2Tx layers using well-controlled liquid-phase co-feeding protocol and electrostatic attraction and investigated its electrochemical performance in sensing early cancer biomarkers, i.e., hydrogen peroxide (H2O2). The molecular-level CuMgAl LDH/Ti3C2Tx superlattice self-assembly possesses superb conductivity and electrocatalytic properties, which are significant for obtaining a high electrochemical sensing aptitude. Electron penetration in Ti3C2Tx layers and rapid ion diffusion along 2D galleries have shortened the diffusion path and enhanced the charge transferring efficacy. The electrode modified with the CuMgAl LDH/Ti3C2Tx superlattice has demonstrated admirable electrocatalytic abilities in H2O2 detection with a wide linear concentration range and low real-time limit of detection (LOD) of 0.1 nM with signal/noise ratio (S/N) = 3. Practically, an electrochemical sensing podium based on the CuMgAl LDH/Ti3C2Tx superlattice has been effectively applied in real-time in vitro tracking of H2O2 effluxes excreted from different live cancer cells and normal cells after being encouraged by stimulation. The results exhibit that molecular-level heteroassembly holds great potential in electrochemical sensors to detect promising biomarkers.