Srikanth Singamaneni (Washington University in St. Louis)
A materials scientist at Washington University in St. Louis is developing a new class of low-cost biosensors with metal nanoparticles that can be used in point-of-care medical testing, chemical detectors, and environmental monitors. Srikanth Singamaneni, a Washington University materials science professor, received last month a five-year, $400,000 Faculty Early Career Development Award from National Science Foundation to support his research.
Singamaneni’s work involves nanomaterials that combine properties of inorganic materials, such as metals, with organic materials, including biological molecules. In this project, Singamaneni aims to create nanoscale metal particles bound to engineered antibodies that detect specific biomarkers, or indicators of disease.
To meet this goal, Singamaneni and colleagues need to overcome significant technical barriers. One hurdle is to engineer antibodies that target only specific biomarkers. He says this part of the research will investigate “the physical and chemical factors that dictate the selectivity of the artificial antibodies” to improve the specificity and sensitivity of the sensors. A key part of the project involves the binding actions between the artificial antibodies and antigens at the molecular level, for which Singamaneni plans to use a technique called surface force spectroscopy, which makes it possible to measure the interactions among individual molecules.
Another obstacle is the instability of antibodies that causes them to degrade quickly, in addition to being expensive and time-consuming to produce. To clear this hurdle, Singamaneni and colleagues are using a technique called surface molecular imprinting, where the target proteins are bound to the surface of gold nanorods. A polymer layer is then added to the outside of the nanorods, but the target proteins are removed, leaving cavities in the polymer layer. When testing a biological substance, such as blood or urine, the target protein — if present — then settles into those cavities.
In the new project, the Washington University team will tag the proteins with polyhistidines, a technique used to purify engineered proteins for biochemical studies. In this case, the polyhistidine tagging also aims to ensure the engineered antibodies bind to the nanorods in a precise way, similar to fitting a piece into a jigsaw puzzle. This precise binding, says Singamaneni, will make it possible to use highly targeted or monoclonal antibodies in the biosensors, thus giving the biosensors the ability to test for a specific molecular chemistry.
To extend this research outside the lab, Singamaneni and colleagues plan to develop and market a nanotechnology kit for students. The kit will enable students to learn more about nanotechnology first-hand by working with nanomaterials in solutions having, for example, varying pH levels that result in different colors.
Read more:
- Nanoparticles Designed to Form Into Tiny Drug-Catching Nets
- Smartphone Biosensor Devised to Detect Toxins, Pathogens
- Antibiotic Resistance Biosensor Developed for Staph Bacteria
- Gold Nanoparticle Biosensor Developed for Simple Diagnostics
- Blood Test Technology Devised with Lab Chip, Smartphone App
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