Alkaline-earth metal ion-modified black phosphorene as a potential platform for anticancer drug delivery and phototherapy: a multiscale computational study

This study presents a computational investigation of black phosphorene (BP) functionalized with alkaline-earth metal ions (Mg 2+ and Ca 2+ ) to explore its potential toward anticancer drug delivery and phototherapy. DFT calculations, supported by QTAIM and NCI analyses, indicate that metal coordination can significantly strengthen the adsorption of the anticancer drug FTCB through dominant electrostatic metal-oxygen interactions, complemented by dispersion forces. Electronic structure calculations reveal bandgap reduction and enhanced charge-transfer character upon drug adsorption, particularly in Mg 2+ -modified systems. Optical properties predict redshifts into the NIR-II region, suggesting possible relevance for near-infrared-mediated photothermal processes. Thermodynamic and kinetic analyses indicate metal-dependent release behavior, with Mg 2+ promoting stronger retention and Ca 2+ enabling comparatively faster thermally assisted release. Additionally, protonation under acidic conditions weakens metal-oxygen interactions, indicating a possible pH-responsive release mechanism. Overall, these findings provide theoretical insights into how alkaline-earth metal-ion functionalization modulates the adsorption and optoelectronic properties of phosphorene-based systems.