Microelectrode arrays of single cell biosensors

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This research will develop methods to engineer cell-material "bio-interfaces" for tailored immobilization of proteins and cells on electrode surfaces and for construction of micro-arrays of single cell-based sensors of high precision, selectivity, sensitivity, and reproducibility. Micro-arrays of cell-based sensors present major design challenges in interfacing cells with materials, especially in an electrode-substrate format. Cell-based sensor technology is severely limited by multiple systematic problems, including (1) methods for attaching cells onto surfaces of designed patterns; (2) unregulated cell growth; (3) loss of cell functionality after cells are attached to electrodes; (4) cell selectivity (affects sensor's signal/noise ratio); and (5) long-term viability of patterned cells. In this work, adhesive proteins or peptides will be patterned onto an electrode array (gold on SiO2) to mediate natural cell attachment and growth. The substrate background (SiO2) will be passivated to resist protein adsorption and cell attachment. This microarray of single-cell biosensors will then be integrated with microelectronic and optical systems to demonstrate its efficacy in drug screening and biothreat detection. Aim 1 will focus on the study of surface modification protocols for covalent binding of PEG onto a silicon oxide background substrate to achieve maximum protein resistance. The effects of surface chemistry on PEG density, stability, and long-term protein rejection will be investigated. Aim 2 will investigate the influence of different proteins/peptides and surface geometry on cell binding for single-cell patterning in order to maintain high cell coverage on the electrodes. Aim 3 will design and fabricate an integrated microarray (IMA) of single-cell based sensors for high-throughput drug screening by integrating surface engineering with the advanced technology of microelectronics. We will develop a comprehensive sensing scheme including hardware implementation, and computational data acquisition and analysis for fast, accurate, and efficient drug screening. Aim 4 will apply the developed IMA sensing system, and complementary FTIR analysis techniques, in two model applications: drug screening and biothreatdetection. To demonstrate the developed sensor's ability to detect and monitor external stimuli, data extracted from the IMA and FTIR studies will be correlated so that practical information can be drawn from biosensor-IMA readings, singly.