Multifunctional hybrid silica nanoparticles for controlled doxorubicin loading and release with thermal and pH dually response.

Controlled drug loading and release into tumor cells to increase the intracellular drug concentration is a major challenge for cancer therapy due to resistance and inefficient cellular uptake. Here a temperature and pH dually responsive PNiPAM/AA@SiO2 core-shell particles with internal controlled release were designed and fabricated for efficient cancer treatment, which could recognize the intrinsic pH differences between cancers and normal tissues. Upon lowering the temperature, doxorubicin was loaded into the PNiPAM/AA@SiO2 nanoparticles, whereas by increasing the acidity, previously loaded doxorubicin was quickly released. Comparing with common mesoporous silica particles (MSNs), this core-shell particle has more uniform size and better dispersity. In addition, dried PNiPAM/AA@SiO2 nanoparticles could be easily redispersed in distilled water. The in vitro cell culture experiments showed that not only PNiPAM/AA@SiO2 particles were more biocompatible and lower cytotoxic than MSN, but also DOX@PNiPAM/AA@SiO2 had higher drug releasing efficiency in the lysosomes and stronger inhibitory effect on tumor cell growth than DOX@MSN. All these features indicated that PNiPAM/AA@SiO2 particles have great potential in therapy applications.