pH and temperature dual-responsive hollow mesoporous silica nanoparticles for drug encapsulation and delivery

In this work, pH and temperature dual-responsive drug delivery vehicles (CDs/PNVCL@HMSNs) with 57.05% drug loading efficiency were prepared. Hollow mesoporous silicon nanoparticles (HMSNs) were synthesized by selective etching. The mixed shells on the surface of HMSNs were composed of carbon dots (CDs) and poly (N-vinylcaprolactam) (PNVCL), which were linked to HMSNs via Schiff base reaction. At room environment (pH = 7.4, T = 25 °C), PNVCL was stretched, so that the model drug Doxorubicin (DOX) could be transported freely through the mesopores. In the blood stream (pH = 7.4, T = 37 °C), PNVCL was collapsed, and DOX was encapsulated to form PNVCL@HMSNs-DOX. CDs were grafted to give CDs/PNVCL@HMSNs-DOX and could further inhibit the leakage of drugs. At the acidic environment of the tumor site, Schiff base bonds broke, leading to shell shedding and DOX release. The drug release could be real-time monitored by the change in fluorescence intensity, which was confirmed by the linear fitting of the fluorescence strength of CDs and the percentage of DOX released. CDs/PNVCL@HMSNs are intriguing drug delivery systems (DDSs), which can combine real-time monitoring and control of drug release.