Tannic acid/Fe3+ complex coated mesoporous silica nanoparticles for controlled drug release and combined chemo-photothermal therapy

Combinational chemo-photothermal therapy holds great potential in improving the therapeutic efficacy for cancer treatment. To achieve this goal, a tannic acid/Fe3+ complex coated mesoporous silica nanoparticle (denoted as MSN-pTA) was prepared. Herein, doxorubicin (DOX) was loaded into MSN for chemotherapy. While the tannic acid/Fe3+ complex could form a pTA layer to be coated on the surface of drug loaded MSN and serve as a photothermal agent for photothermal therapy (PTT). The obtained MSN-pTA was spherical particles around 200 nm and carried a negative surface charge of − 43 mV. The pTA coating exhibited remarkable photothermal conversion ability upon the near infrared (NIR) light irradiation and this effect was related with the pTA concentration as well as the ratio of Fe3+ in pTA. Moreover, MSN-pTA demonstrated excellent photostability during multiple times of laser irradiation. DOX was encapsulated into MSN-pTA with a loading efficiency of 6.75% and could be preferably released in acidic environment as a result of decreased drug-carrier interaction and the disassembly of pTA. The [email protected] plus laser treatment showed significantly enhanced cytotoxicity against the 4T1 tumor cells compared to that without laser irradiation. And the result of animal studies showed that [email protected] plus laser irradiation effectively raised the temperature at tumor site and exhibited the strongest tumor inhibition compared to single chemotherapy or PTT. These results collectively confirmed the potential of [email protected] for combined chemo-photothermal therapy with enhanced anti-tumor efficacy.