Research

Beyond their aesthetic appeal, molecular links and knots are worthy synthetic targets that expand the chemist’s repertoire of potential building blocks for the engineering of nanoscale devices. [2]Catenanes ([2]C), trefoil knots (TK), and Solomon links (SL) are three such idealized topologies that have been realized synthetically. Although a wide variety of [2]C (mechanically interlocked molecules comprised of two macrocycles) have been synthesized by statistical, covalent, or template-directed methods, there are significantly fewer examples of efficient construction of molecular TKs and SLs.

Recently, we have reported the simultaneous preparation of the three links (Figure) from a simple pair of chelating ligand in a one pot synthesis. The output of this research was published in Angewandte Chemie and selected to appear on the inside cover. Efforts in the functionalization of these structures and their incorporation into materials is undergoing in our research group.

A major challenge in medicine is the efficient distribution of drugs in the body. To improve drug bioavailability, researchers seek to develop non-toxic transport agents (or vectors) as nanoparticles. Our research focuses on developing intelligent multimodal nanoplatforms that specifically target disease and / or symptom and allow the controlled release of active molecules. This platform will simultaneously accumulate a maximum of additional properties such as therapy, targeting, and imaging and will be used to treat various pathologies and simultaneously monitored the disease by imaging, while controlling the progressive drug release.

One of our strategies relies on combining the recognition abilities of cucurbituril macrocyles and the properties of iron oxide nanoparticles as contrast agent (Figure). Iron oxide (g-Fe2O3) nanoparticles (NPs) were efficiently coated with the water soluble macrocycle cucurbit[7]uril (CB[7]) by microwave heating. Nile red dye was loaded into the cavities of the surface-adsorbed CB[7]s, and intracellular delivery of the dye to HCT116 cells was observed by confocal laser scanning microscopy. The stability, biocompatibility, and dual purpose functionality such as drug delivery and magnetic resonance imaging of the CB[7]NPs herald the theranostic potential of this system.

The ability to prompt a fast and reversible movement of large amplitude in molecular bodies has appeared as a major scientific objective which is mainly driven by exciting foreseen applications in nanoscience. From this promising and highly competitive domain, a large number of nanometric small-scale mimics of macroscopic tools known as molecular machines such as tweezers, gears, rotors, shuttles, muscles, and elevators that fulfill these requirements, have been designed to respond to various external stimuli, such as pH, redox change, temperature and light. We have employed these design principles in the synthesis and operation of electrochromic materials.

Articles:

• Journal of Material Chemistry C, 2013, 2302–2307.
  Intramolecular redox-induced dimerization in a viologen dendrimer