Mesoporous silica nanoparticles (MSNs), feature well-defined nano-sized pores, and have therefore been actively studied as drug delivery vehicles. However, their performance is greatly challenged by cargo leakage and premature release.

Ying-Wei Yang at Jilin University, Changchun, China, Hui Gao at Tianjin University of Technology, Tianjin, China, and colleagues have developed a layer-by-layer coating strategy based on non-covalent interactions for building pH-responsive MSN drug carriers. Loaded with anticancer drugs, the MSNs are coated with cucurbit[7]uril-bridged polymer layers, where the amine terminals of the polymer are encapsulated in cucurbit[7]uril. In low pH environments, such as cancer cells, the coating dissembles and triggers the release of drugs.

The researchers have demonstrated both in vitro and in vivo cancer cell-targeting drug delivery with high efficiency using this system. As an inherently flexible functionalization method for MSNs, its selective response can be easily tuned by changing coating units.

• Mesoporous Silica Nanoparticles Coated by Layer-by-Layer Self-assembly Using Cucurbit[7]uril for in Vitro and in Vivo Anticancer Drug Release
  Qing-Lan Li, Yanfang Sun, Yu-Long Sun, Jijie Wen, Yue Zhou, Qi-Ming Bing, Lyle D. Isaacs, Yinghua Jin, Hui Gao, Ying-Wei Yang
  Chem. Mater. 2014.
  DOI: 10.1021/cm503304p