Biomimetic Approach for Drug Delivery and Diagnostic Applications

The field of drug delivery has seen unprecedented growth in the last couple of decades. Carrier mediated drug delivery, in particular, has received tremendous attention due to the various advantages over conventional delivery methods. Numerous carriers with different physical and chemical characteristics have been developed for drug delivery and diagnostic applications. However, only a handful of these carriers have entered clinical practice. The major reason is rapid clearance of carriers by the body's immune system. An ideal drug delivery carrier would be one which can circulate in blood for a prolonged period of time, selectively accumulate at the target site and release the desired drug in a controlled manner. While there have been numerous attempts to achieve this goal by optimization of different physical and chemical features, we are still far from having an ideal carrier. On the other hand, natural cells such as red blood cells, platelets and certain pathogens have evolved to perform complex biological tasks of interest to drug delivery carriers with great sophistication. The unique physical features of these cells play a crucial role in their biological function. Hence, we adopted a novel biomimetic approach in fabricating particles that mimic these biological cells.;In particular, we fabricated nano and micro-particles that mimic the various structural and functional features of biological cells including red blood cells, platelets and different types of bacteria and viruses using novel fabrication techniques. The interaction of these particles with the body's immune system especially with the macrophages that play a crucial role in the clearance of carriers was studied. The importance of particle size, shape, mechanical properties and surface chemistry in its biological performance was outlined. Synthetic cells hold tremendous potential in various biomedical applications including targeted drug delivery, controlled release and diagnostic imaging. Synthetic blood cells show great promise in artificial blood based applications. Toxicity studies were carried out to confirm the safety in using these particles for biomedical applications. The findings reported here have significant implications in fundamental understanding of the different physical and chemical attributes of biological cells and therapeutic carriers as well as in engineering novel carriers for drug delivery and diagnostic applications.