Uptake or release of molecules in the extracellular space is an important indicator of physiological or pathophysiological state of cells. Our laboratory is developing novel biosensors for detection of molecules secreted or taken up by cells. Our interests here are not only in the development of novel sensing strategies but also in designing methods for integrating miniature biosensors in the immediate vicinity of cells, in the desired locations of the surfaces. Our analytes of interest range from small molecules (e.g. glucose, lactate, hydrogen peroxide) to proteins (e.g. cytokines). To detect these analytes we are pursuing the following biosensing strategies. 1) We are developing enzyme-based electrochemical biosensors that can double as cell culture chambers and may be used for detection of glucose, lactate or hydrogen peroxide at the site of cells. 2) We are developing antibody- or aptamer-based biosensors for detection of proteins secreted by cells. Analytes include serum proteins (albumin, alpha fetoprotein) secreted by liver cells and inflammatory cytokines (IFN-g, TNF-a) released by activated immune cells.
Microbiosensors integrated with cells. (A) Macrophages reside in the immediate vicinity of an optical biosensor for hydrogen peroxide detection. (B) A single macrophage captured next to peroxidase-containing gold electrode for detection of secreted hydrogen peroxide. This micropatterned surface also contained antibodies for detection of TNF-a. Secretion of this cytokine is seen near the cell (red fluorescence). (C) Hydrogel microwells with integrated beacons for IFN-g detection. Green fluorescence appears immediately, in real-time upon introduction of IFN-g without the need for secondary labeling.
People contributing to this research direction: Ying Liu, Qing Zhou, Tim Kwa, James Enomoto, Zimple Matharu, Gulnaz Stybayeva
Important recent papers on this topic: Liu, Y., Tuleuova, N., Ramanculov, E., Revzin, A. “Aptamer-based Electrochemical Biosensor for Interferon Gamma Detection” Analytical Chemistry, 2010, 82, 8131-8136
Tuleuova, N., Jones, C.N., Yan, J., Ramanculov E., Yokobyashi, Y., Revzin A. “Development of an Aptamer Beacon for Detection of Interferon-Gamma” Analytical Chemistry, 2010, 82, 1851-1857
Yan, J., Pedrosa, V., Simonian, A.L., Revzin, A. “Immobilizing Enzymes onto Electrode Arrays by Hydrogel Photolithography to Fabricate Multi-Analyte Electrochemical Biosensors” ACS Applied Materials & Interfaces, 2010, 2, 748-755
Yan, J., Sun, Y., Zhu, H., Marcu, L., Revzin A. “Enzyme-Containing Hydrogel Micropatterns Serving a Dual Purpose of Cell Sequestration and Metabolite Detection” Biosensors & Bioelectronics, 2009, 24, 2604-2610