Preparation Of Drug Nanoparticles Based On NIR-Activated Supersensitive Polymer For Cancer Therapy

Near infrared(NIR)light-activated delivery release via the photothermal conversion are of particular interest due to its advantages in spatial and temporal control.However,the NIR light-activated drug release from polymeric nanoparticles was rarely reported.It might be because the most widely used polymer as delivery systems has a rigid chain,which hindered unit motion relative to each other during photothermal conversion processes that limit the diffusion of drug molecules.In this study,we report observations on the NIR-activated super-sensitive drug release from polyphosphoester based polymeric nanoparticles.We demonstrate that only 5 s NIR i rradiation(808 nm,0.3 W cm-2)led to 17.8% of DOX release,while its release almost completely stopped when the NIR laser is switched off.More importantly,the NIR light-activated drug release was observed when the same NIR irradiation(5 s)was repeated every five minutes.In contr ast,the control poly(d,l-lactide)based nanoparticles(the most used polymeras delivery system)did not exhibit such NIR-activated drug release.We found that such NIR-activated super-sensitivity is derived from its hydrophobic flow core,the flexible polymer chain of polyphosphoester facilitate drug diffusion when exposed to the NIR laser within a short time.The control nanoparticles with the rigid core did not exhibit NIR-activated release profiles.Furthermore,we demonstrated that such NIR light-activated super-sensitive drug release from nanoparticles significantly enhanced its anticancer efficacy,resulting in the overcoming of the resistance of cancer cells against DOX treatment in vitro and in vivo.This simple and highly universal strategy provided new approach to fabricate NIR light-activated super-sensitive drug delivery systems.