A label-free, rapid multimarker protein impedance-based immunosensor

A multiplexing, multimarker protein immunosensor based upon electrochemical impedance spectroscopy was designed, fabricated, and analyzed. The antibody based molecular recognition element sensor was demonstrated using five inflammatory cytokines and receptors (Figure 1). These pro- and anti-inflammatory markers are used in cellular signaling and could be useful in early detection of diseases including Multiple Sclerosis, cancer, or pathogenic infection. The disposable strip of five sensors was characterized over four orders of magnitude of target protein concentration. The assay takes only 90 seconds from sample introduction to impedance output in a label-free manner. The goal of this work is to develop a platform technology that can be made reproducible, scalable, and efficient for high throughput screening for proteomic markers of disease. These sensors detect the markers at the respective physiological ranges found in vivo, albeit in purified fashion. Electrochemical Impedance Spectroscopy (AC impedance) was chosen as the appropriate (label-free and rapid) approach resulting in signals that are discernible using a simple, rapid strip sensor platform that is readily scalable to accommodate future high throughput screening. This scalability could allow for the detection of 100's of proteins, or the antibody immunosignatures themselves.