Development of a pH-Responsive Co1-XS@ Chi-TPP Nanoplatform for Dual Antibacterial and Anticancer Therapy

Monodisperse Co_1-XS nanospheres were synthesized via a solvothermal method. To enhance their stability and performance, the cobalt sulfide nanospheres were surface-modified using chitosan cross-linked with tripolyphosphate (Chi-TPP). Subsequently, doxorubicin (DOX), a widely used chemotherapeutic drug, was loaded onto the Co_1-XS@Chi-TPP nanoplatforms. The DOX release studies under different simulated conditions demonstrated pronounced pH-responsive behavior, with 63% cumulative release observed in the simulated tumor microenvironment (TME) after 24 h. Kinetic and dynamic light scattering (DLS) analyses revealed that DOX release is mainly diffusion-controlled at physiological pH but accelerated under acidic TME conditions, reflecting the pH-responsive, multiphasic behavior of the nanosystem driven by polymer swelling. The Co_1-XS@Chi-TPP nanoplatforms exhibited antibacterial …