A novel microwave stimulus remote-controlled anticancer drug release system based on Janus TiO2-&mSiO2 nanocarriers

In this work, we used a simple method to construct Janus-shaped TiO 2- x & m SiO 2 nanoparticles composed of gray-black titanium dioxide (TiO 2- x ) and mesoporous silica ( m SiO 2 ) serving as carriers to improve the microwave-controlled release performance. In the composite materials, on one hand, the rod-shaped m SiO 2 could realize high-efficiency drug loading, on the other hand, spherical TiO 2- x featuring oxygen vacancy acted as the main microwave absorber. The overall spatial separation between titanium dioxide and silicon dioxide was crucial to enhance microwave conversion efficiency. The Janus-liked nanomaterial was made up of TiO 2- x nanosphere with a diameter of approximately 180 nm on one end and rod-shaped mesoporous silica with about 220 nm in length and 100 nm in diameter on the other end, and the specific surface area of the entire material was 203.25 m 2 /g. Meanwhile, the cumulative doxorubicin hydrochloride (DOX) loading rate of the carrier reached up to 38 wt% after 24 h. The loading process of the DOX was exothermic, and the noncovalent interaction between the DOX and Janus TiO 2- x & m SiO 2 carrier was mainly van der Waals force. Furthermore, the rates of drug release at 24 h were up to 61 wt%, 69 wt% and 89 wt% at pH 7.0, 5.0 and 3.0, respectively. After microwave stimulation at pH 7.0, the rate of drug release increased observably from 61% to 88% compared to that of non-microwave irradiation. The order of the microwave thermal conversion capability of the samples was Janus TiO 2- x & m SiO 2 > Janus TiO 2 & m SiO 2 > core-shell TiO 2- x @ m SiO 2 . Besides, cytotoxicity tests indicated that Janus TiO 2- x & m SiO 2 nanoparticles had good biocompatibility. Therefore, the multifunctional carrier of the Janus-shaped configuration could not only release drugs under pH control, but also be further triggered by microwave stimulation. The Janus-shaped TiO 2- x & m SiO 2 nanoparticles will look forward to laying foundation to the application in drug delivery systems. A schematic of Janus TiO 2- x & m SiO 2 nanocarrier formation and subsequent microwave triggered drug release process. A morphology, integrating a microwave-absorbing spherical structure and a mesoporous construction to realize a novel Janus-shaped TiO 2 -based drug carrier, was designed. The TiO 2 part was reduced to a non-ratio gray-black TiO 2- x , which resulted in its reduced bandgap and enhanced its microwave absorption performance. In addition, the interface polarization of the two materials and the multiple reflections of microwaves by the pore structure were also ways to improve microwave absorption. The rod-shaped mesoporous SiO 2 on one end of the spherical titanium dioxide for the drug loading. Janus TiO 2- x & m SiO 2 carrier will be used as a functional material for biomedical applications of drug uploading and microwave/pH dual controlled release drugs. • A novel Janus TiO 2- x & m SiO 2 nanoparticles were prepared via a simple method. • Clarified the formation mechanism of Janus TiO 2- x & m SiO 2 nanoparticles • Janus TiO 2- x & m SiO 2 nanoparticles could be used for microwave-controlled drug release. • Clarified the microwave absorption mechanism of Janus TiO 2- x & m SiO 2 nanoparticles