112. protease-based magnetic sensor for rapid detection of candidemia

Department: Electrical & Computer Engineering
Faculty Advisor(s): Drew A. Hall | Anthony O'Donoghue

Primary Student
Name: Sonal Jain
Email: s7jain@ucsd.edu
Phone: 858-534-3855
Grad Year: 2017

Abstract
We are developing a rapid, point-of-care (POC) test for detection of Candidemia using giant magnetoresistive (GMR) biosensors. Candidemia is a fungal infection caused by the overgrowth of a yeast called Candida albicans. It is the 4th leading cause of bloodstream infections in hospitalized patients in the U.S. and severely affects immunocompromised individuals. Candidemia can be fatal if not treated rapidly and is often only detected post-mortem. The current gold standard for its detection is a blood culture, which typically takes 3-5 days, wasting precious treatment time. Therefore rapid, unambiguous diagnosis is required to improve prognosis. Our technology detects a unique enzyme activity that is secreted by C. albicans during infection. This enzyme, Sap6, is a protease that can degrade a synthetic peptide. Our POC test works by immobilizing magnetic nanoparticles onto the GMR biosensor via the peptide. Once peptide cleavage by Sap6 occurs, the magnetic nanoparticle is released and floats away from the sensor surface. This change in the magnetic field of the GMR sensors is detected in real-time. We have demonstrated this proof-of-concept in a 96-well plate format using a fluorescent sensor. This assay immobilizes approximately 1.8 g of peptide per well which can then be released by 13.34 g of protease in 10 minutes at room temperature. We are currently working on translating the assay to the GMR biosensors and optimizing the test further for detection of other diseases like cystic fibrosis.

Industry Application Area(s)
Electronics/Photonics | Life Sciences/Medical Devices & Instruments

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