pH and Ultrasound Dual-Responsive Polydopamine-Coated\nMesoporous Silica Nanoparticles for Controlled Drug Delivery

Abstract

A pH- and ultrasound\ndual-responsive drug release pattern was successfully\nachieved using mesoporous silica nanoparticles (MSNs) coated with\npolydopamine (PDA). In this paper, the PDA shell on the MSN surface\nwas obtained through oxidative self-polymerization under the alkaline\ncondition. The morphology and structure of this composite nanoparticle\nwere fully characterized by a series of analyses, such as infrared\n(IR), transmission electron microscopy, and thermogravimetric analysis.\nDoxorubicin hydrochloride (DOX)-loaded composite nanoparticles were\nused to study the performances of responsive drug storage/release\nbehavior, and this kind of hybrid material displayed an apparent pH\nresponse in DOX releasing under the acidic condition. Beyond that,\nupon high-intensity focused ultrasound exposure, loaded DOX in composite\nnanoparticles was successfully triggered to release from pores because\nof the ultrasonic cavitation effect, and the DOX-releasing pattern\ncould be optimized into a unique pulsatile fashion by switching the\non/off status. From the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium\nbromide assay, it was observed that our blank nanoparticles showed\nno toxicity to HeLa cells, but DOX-loaded nanoparticles could inhibit\nthe growth of tumor cells. Furthermore, these composite nanoparticles\ndisplayed an effective near-IR photothermal conversion capability\nwith a relatively high conversion efficiency (∼37%). These\nas-desired drug delivery carriers might have a great potential for\nfuture cancer treatment that combine the chemotherapy and photothermal\ntherapy.