Princeton Docket 10-2626/2696-1
Researchers at Princeton have developed a new design of electronic sensor for the detection of pathogenic bacteria. Princeton is seeking an industrial partner to commercialize this technology.
Current methods for detecting pathogenic bacteria include enzyme-linked immunoassay (ELISA), and polymerase chain reaction (PCR). ELISA exploits antibodies as molecular recognition elements due to their highly specific targeting of antigenic sites. However, antibodies lack the stability needed to detect pathogenic species under harsh environments, reducing the shelf-life of antibody functionalized sensors. The high specificity of antibody-antigen interactions also requires a one-to-one pairing of antibody-based sensors for each target to be detected. PCR can reach single-cell detection limits, yet requires the extraction of nucleic acids and is limited in portability.
The current state-of-the-art for detecting bacterial contamination in drugs, products and devices that come in contact with blood is the limulus amebocyte lysate (LAL) test. The test procedure itself is time-consuming and the test material preparation requires the culling of horseshoe crabs which is expensive and becoming increasingly ecologically problematic.
This new method employs biosensors which combine the natural specificity of biological recognition with sensitive, label-free sensors providing electronic read-out. It is based on antimicrobial peptide-functionalized microcapacitive electrode arrays. Using a naturally occurring antimicrobial peptide and exposing the sensor to various concentrations of pathogenic E. coli, the device demonstrates detection limits of approximately 1 bacterium/µL, a clinically useful detection range. The peptide-microcapacitive hybrid device was further able to demonstrate both Gram-selective detection as well as inter-bacterial strain differentiation, while maintaining recognition capabilities toward pathogenic strains of E. coli and Salmonella.
Antimicrobial peptides are much more stable than typical globular proteins, as such, they can retain functionality while being continually exposed to the environment. The replacement of current antibody based affinity probes with more stable and durable antimicrobial peptides in biological sensors may thus help to increase the shelf-life of current diagnostic platforms. Lastly, a major potential advantage of antimicrobial peptides as recognition elements stems from their semi-selective binding nature to the target cells, affording each peptide the ability to bind to multiple pathogenic cells.
It is anticipated that this new device may also be useful for real-time on-chip monitoring of flowing water supplies.
US Patent 9,029,168
Manu S. Mannoor, Siyan Zhang, A. James Link, and Michael C. McAlpine. Electrical detection of pathogenic bacteria via immobilized antimicrobial peptides. PNAS. 2010 vol. 107 no. 45 19207-19212.
Manu S. Mannoor, Hu Tao, Jefferson D. Clayton, Amartya Sengupta, David L. Kaplan, Rajesh R. Naik, Naveen Verma, Fiorenzo G. Omenetto and Michael C. McAlpine. Graphene-based wireless bacteria detection on tooth enamel. Nat. Commun. 2012. 3:763. doi: 10.1038/ncomms1767.