Construction Of NIR-Actived Nanoscale Carrier-free Drug Delivery System For "Bomb-like" Drug Release

Carrier-free nanoparticles with high drug loading have attracted increasing attention;however,in situ on-demand drug release remains a challenge.Here,a novel near-infrared（NIR）laser-induced blasting carrier-free nanodrug delivery system is designed and fabricated by coating doxorubicin（DOX）nanoparticles（DNPs）with a polydopamine film（PDA）that would prolong the blood circulation time of DNPs and avoid the preleakage of the DOX during blood circulation.Meanwhile,the NH₄HCO₃is introduced to trigger in situ“bomb-like”release of DOX for the production of carbon dioxide（CO₂）and ammonia（NH₃）gases driven by NIR irradiated photothermal effect of PDA.Both in vitro and in vivo studies demonstrate that the carrier-free nanovectors with high drug loading efficiency（85.8%）prolong tumor accumulation,enhance chemotherapy,achieve the synergistic treatment of chemotherapy and photothermal treatment,and do not induce any foreign-body reaction over a three-week implantation.Hence,the delicate design opens a selfassembly path to develop PDA-based NIR-responsive multifunctional carrierfree nanoparticles for tumor therapy.