Nanomedicine

A new paradigm in diagnostics and therapy

The focus of research in our laboratory is to explore biomedical applications of nanotechnology. Nanoparticles and nanomaterials offer potential benefit in wide range of applications such as in sensing, diagnostics, delivery and image enhancement. This field of science offers unique approaches to probe and control a variety of biological and medical processes that occur at nanometer length scales and is expected to have a revolutionary impact on biology and medicine. In the Sridhar lab, specific research projects are investigating use of nanoparticles for cellular imaging and nanoporous templates for drug delivery applications.

Magnetic nanoparticles as MRI contrast enhancement agent

Magnetic nanoparticles in the form of superparamagnetic iron oxide nanoparticles are increasingly being used as contrast enhancement agent in magnetic resonance imaging (MRI). Our approach is through micelle-based nanotechnology platform. In this experiment 10 nm iron oxide nanoparticles are loaded within the hydrophobic core of PEG2000-DSPE micelles resulting in average size of 30-50 nm micelles. Tumor-specificity is then achieved via conjugation of antinuclear antibody 2C5 to hydrophilic tail of these micelles. Figure 1 shows uptake of antibody-labeled micelles loaded with magnetic nanoparticles by human breast tumor BT20 cells. Characterization of these micellelar systems for use as contrast agents were carried out using SQUID and NMR. In addition, the group is also working on using these magnetic nanoparticles-loaded micelles for magnetic hyperthermia in cancer therapy to selectively kill tumor cells.

In-vitro cellular imaging using gold nanoparticles

This research project is exploring use of gold nanoparticles as a novel tool for cellular imaging. Nobel-metal nanoparticles such as gold and silver upon absorption of multiple photons, under special conditions, give rise to photoluminescence. This technique has potential as an alternative to traditional dye-based staining and labeling of biological samples. Using a Ti-sapphire laser as excitation source, photoluminescence from gold nanoparticles was observed from within two different systems - dictyostelium discoideum and mouse embryonic stem cells were used for in-vitro cellular imaging. They were able to show that through the process of endocytosis, gold nanoparticles are internalized in these cells. Figure 2 is the photoluminescence from gold nanoparticles used as a tool for cellular imaging in dictyostelium discoideum (Fig. 2). This has allowed the group to investigate the use of gold nanoparticles as an imaging tool that offers several advantages including non-cytotoxicity, lack of photobleaching and improved cellular tracking.

Nanoporous alumina and titania templates for drug/gene delivery

New generations of biomedical implants and cardiovascular stents that are currently being used have the property of localized elution of drug molecules to enhance lifetime of these devices and for bio-integration. In this project Sridhar group is using nanoporous alumina and titania coatings for localized drug and gene delivery applications. They have fabricated nanoporous alumina and titania films on metal substrates with precise control on pore diameter, interpore distance and film thickness (Fig. 3).

As a proof-of-concept for drug-loading within these films, dye-labeled polystyrene beads were filled within nanoporous alumina templates (Fig. 4). The group is now working on in-vitro experiment to study loading and release of plasmid DNA and drug molecules from these nanoporous alumina templates.