UC Riverside

Tools for the rapid assessment of diseased condition and underlying causative agent, disease progression and treatment outcome are prerequisites to meeting the goal of providing best health care possible. These tools should be highly selective and sensitive, show rapid response and of low cost for their wide spread use. Utilizing the growing knowledge about the organisms/conditions causing the diseased state, identifying suitable biomarkers and by incorporating newer technologies, novel diagnostics tools with above mentioned qualities can be built. Utilizing Single walled carbon nanotubes (SWNTs) we have built biosensors for detection of Protective antigen (PA) toxin secreted by anthrax causing bacteria and ultra-sensitive detection of glucose in unconventional body fluids. These nano-biosensors display high sensitivity and selectivity for the target can be easily adapted to develop point of care devices. Through these sensors we have established a methodology for SWNT based sensor fabrication and shown different modes of operation for detection of both charged and uncharged analytes. Utilizing fluorescence based protein probe, we have developed an in vivo assay for HIV detection. This probe is sensitive to HIV protease, which is synthesized during its replication and plays an important role in formation of viable viral progeny. We are also able to assess the HIV protease activity in vivo against several wild type and mutant versions of its natural cleavage sites. These quantified kinetic parameters will help in gaining better understanding of protease-substrate and protease-inhibitor interactions. By mimicking the drug resistance causing protease and cleavage site mutations in our assay we can capture the altered kinetics and gain understanding of their contribution to resistance towards protease inhibitors. Our cell based assay is a better choice than the in vitro assays for screening newer inhibitors as it mimics the natural environment encountered by the enzyme and also provides the initial bioavailability and toxicity data for the candidate drugs.