An implantable antibacterial drug-carrier: Mesoporous silica coatings with size-tunable vertical mesochannels

Implant-associated bacterial infection remains one of the most common and serious complications. Therefore, a surface boasting long-term antibacterial ability for implants is highly desirable. Herein, mesoporous silica coatings (MSCs) with vertical and size-tunable mesochannels are fabricated on a variety of metal substrates via a nano-interfacial oriented assembly approach. Such facile and versatile approach relies on the vertically oriented fusion of composite micelles on the nanoscale flatness surface of substrates. Such orientation assembly process endows the MSCs with vertical mesochannels, tunable mesopore size (ca. 5.5–13.5 nm), and switchable substrates even with complex and diversified surfaces. Importantly, the MSCs on titanium substrates (Ti@MSCs) exhibit excellent performances for drug adsorption and sustained release. The saturation adsorption capacity can reach 0.544 µg·cm−2 towards minocycline hydrochloride (MC-HCl) antibiotic molecules, which is 6.5 times as the bare titanium (Ti) substrate. In addition, the drug release time can be controlled from 84 to 216 h by simply adjusting the mesopore size. As a proof of concept, the Ti@MSCs can realize a higher antibacterial rate (95.9%), compared with the bare Ti (70.3%). The results highlight the high potential of MSCs as implant coating for long-term preventing and eliminating peri-implantitis.