Carbonaceous- and Layered-material based Hybrids for Drug Delivery and Catalysis
In this presentation, I will talk about synthesis and characterization of various hybrid materials and their applications in drug delivery and catalysis. Carbonaceous nanospheres derived from glucose show preferential accumulation into the mice brain. We have modified the surface of these spheres with magnetic (Prussian blue and its analogues) nanoparticles and luminescent (lanthanide) probes to make brain theranostic agents. These multifunctional hybrid spheres showed enhanced magnetic and luminescent behaviour. They were biocompatible, entered brain, and showed no toxicity to the mice. The method of fabrication was versatile and could be used to create a number of theranostic systems for brain. Hybrid nanoparticles were synthesized from glucose derived carbon and iron oxide in the form of different morphology. Depending on their shape, these nanoparticles could compartmentalize inside the brain cells in the in vivo conditions. Biconcave shape of nanoparticles showed preferential nuclear entry, whereas nanotube morphology was restricted to the cytoplasm. Also, shape dependent compartmentalized delivery of an activator of an epigenetic enzyme was demonstrated. Smart hybrid nanospheres were prepared using layered clay and polyelectrolytes in a layer-by-layer fashion. These hybrid spheres showed reversible size change (about 60%) in response to pH, in the range of physiologically relevant pH values. Hybrids were also demonstrated for their pH dependent drug release ability. Catalytic behaviour of layered boron nitride and boron nitride supported metals towards oxidative dehydrogenation of propane was studied. Boron nitride (a generally accepted inert material) catalysed the propane oxidative dehydrogenation reaction. The catalytic activity was found to improve with increasing surface area of the catalyst. The catalytic activity was stable for nearly 5 hours and could be regenerated easily by heating in dilute ammonia. Oxidation of surface B-N bonds in oxygen leads to the diminishing catalytic activity, which on heating in ammonia reduced back to their native form regaining the indigenous catalytic activity. Remarkably, the high propene selectivity and yields obtained for these metal free catalysts were comparable to the reported catalysts and could be further increased by using higher surface area boron nitride samples.
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