Smart Hybrid Materials (SHMs)
Khashab Research Group
Innovatively Functionalized Nanomaterials for Biomedical, Sensing and Composites Applications


Mechanised Nanoparticles for Drug Delivery

Coti, K. K.; Belowich, M. E.; Liong, M.; Ambrogio, M. W.; Lau, Y. A.; Khatib, H. A.; Zink, J. I.; Khashab, N. M.; Stoddart, J. F. Mechanised Nanoparticles for Drug Delivery. Nanoscale 2009, 1, 16-39
Coti, K. K.; Belowich, M. E.; Liong, M.; Ambrogio, M. W.; Lau, Y. A.; Khatib, H. A.; Zink, J. I.; Khashab, N. M.; Stoddart, J. F.
Mechanised, nanoparticles, drug delivery
A review. Time and time again humanity is faced with a unifying global crisis that crosses the many great divides in different societies and serves to bring once segregated communities back together as a collective whole. This global community instinctively turns to science to develop the means of addressing its most pressing problems. More often than not, these forces dictate the direction that scientific research takes. This influence is no more apparent than in the field of supramol. chem. where, for decades now, its responsibility to tackle such issues was put on the back burner as a consequence of a lack of platforms with which to deliver this contemporary brand of chem. to meaningful applications. However, the tide is slowly turning as new materials emerge from the field of nanotechnol. that are poised to host the many attractive attributes that are inherent in the chem. of these supermols. and also in the mechanostereochem. of mech. interlocked mols. (MIMs), which can be reused as a sequel to supramol. chem. Mesoporous silica nanoparticles (SNPs) have proven to be supremely effective solid supports as their surfaces are easily functionalized with either supermols. or MIMs. In turn, the blending of supramol. chem. and mechanostereochem. with mesoporous SNPs has led to a new class of materials - namely, mechanized SNPs that are effectively biol. nanoscale "bombs" that have the potential to infiltrate cells and then, upon the pulling of a chem. trigger, explode! The development of these materials was driven by the need to devise new therapies for the treatment of cancer. Recent progress in research promises not only to control the acuteness of this widespread and insidious disease, but also to make the harsh treatment less debilitating to patients. This global scourge is the unifying force that has brought together supramol. chem., mechanostereochem. and nanotechnol., uniting these 3 communities for the common good. At the nanoscale level, the mechanism for the release of cargos from the confines of the nanopores in the SNPs is accomplished by way of mech. modifications made on the surface of these functionalized supports. These mech. motions rely on both supramol., i.e., host-guest complexes, and mechanostereochem. phenomena (e.g., bistable rotaxanes), which are often stimulated by changes in pH, light and redox potentials, in addn. to enzymic catalysis. The future of this field lies in the development of "smart bombs" wherein the loaded mechanized SNPs are endocytosed selectively by cancer cells, whereupon an intracellular trigger causes release of a cytotoxin, effectively leading to apoptosis. This review serves to highlight (1) the evolution of surface-functionalization of SNPs with supermols. and also with MIMs, (2) the mechanisms through which controlled-release of cargo from mechanized SNPs occurs, and (3) results from the in vitro application of these mechanized SNPs.