Cobalt Phosphide Nanorods with Controlled Aspect Ratios as Synergistic Photothermo-Chemotherapeutic Agents

Polydopamine-capped cobalt phosphide nanorods (Co2P@PDA NRs) with six aspect ratios (ARs) from 1.4 to 10 are synthesized by a one-step thermal decomposition and microemulsion method. The NRs with AR ∼ 6.4 show good dispersibility in physiological solutions, exhibiting an outstanding near-infrared (NIR) photothermal performance because of a high molar extinction coefficient of 13.08 L g–1 cm–1 at 980 nm, excellent photostability, a photothermal conversion efficiency (PCE) of ∼64%, and no obvious cytotoxicity to various types of cells. Coupled with NIR excitation, folic acid conjugation to the doxorubicin-loaded NRs (AR ∼ 6.4) helped them in securing targeted and controlled drug release to the cancer cells. The synergistic photochemothermal property of Co2P@PDA NRs offers itself as a worthy candidate in tumor theranostic applications.