MXene–aptamer functionalized electrochemical biosensor for wearable breast cancer detection: A comprehensive theoretical and computational investigation

Breast cancer remains the most frequently diagnosed malignancy among women worldwide, with early detection being the single most critical factor for improved survival outcomes. This work presents a comprehensive theoretical and computational investigation of a proposed wearable electrochemical biosensor based on Ti 3 C 2 T x MXene nanosheets functionalized with high-affinity aptamers for the multiplexed detection of breast cancer biomarkers (HER-2, MUC1, and CA15–3). The sensor concept integrates a flexible textile substrate with a screen-printed three-electrode configuration, incorporated into a bra strip for continuous, home-based screening. We emphasize that all sensor figures-of-merit reported in this work including limit of detection (LOD), stability, selectivity, and reproducibility (RSD) are purely computational predictions representing theoretical upper-bound performance. No experimental validation has been performed, and real-world performance is expected to be inferior to these idealized values. Density functional theory (DFT) calculations employing H 2 S as a simplified surrogate for the much larger protein biomarkers, and without atomistic inclusion of the aptamer reveal a strong chemisorption energy of − 1.24 eV at the Ti-top site, with a significant charge transfer of 0.42 e from the surrogate molecule to the MXene layer. Electronic structure analysis shows an increase in the density of states at the Fermi level upon target binding. Electrochemical simulations, based on Butler–Volmer kinetics and Langmuir adsorption, predict a theoretical detection limit of 1 pg/mL for HER-2 (1 fg/mL for the multiplexed system), a linear range of 1 pg/mL to 100 ng/mL, and a response time of 12 s. Selectivity is assessed only against gas-phase surrogates (CO, NH 3 , NO 2 , CH 4 ); biologically relevant interferents are discussed as a limitation with estimated responses. Long-term stability and reproducibility are modelled phenomenologically rather than measured. A miniature potentiostat with Bluetooth Low Energy (BLE) communication is conceptually proposed for wireless data transmission. This work establishes a theoretical baseline and identifies critical translational barriers that must be resolved experimentally before any clinical application can be considered.