This Small Business Innovation Research Phase I project aims to develop a handheld automated biosensor for specific and sensitive detection and quantification of proteins and/or pathogenic cells in liquid samples. The biosensor will integrate highly-specific immunodiagnostics with ultra-sensitive electrochemical sensors in a microfluidic format, and will have the following features: (1) Quantitative detection of pathogenic bacteria and protein markers in any liquid sample, (2) Low detection limit (i.e. less than 100 cfu/ml for pathogens and less than 0.1 ng/ml for proteins), (3) Short assay times (i.e. less than 25 minutes for bacterial cells and less than 10 minutes for proteins), (4) Single-button, fully-automated operation requiring minimal user interaction, and (5) Handheld, battery powered operation allowing its use in remote locations. In this Phase I project, the utility of the system will be demonstrated by detecting Escherichia coli (a representative pathogen) and Immunoglobulin G (a representative protein/immuno marker).<br/><br/>The commercial applications of the proposed product would include health clinics and mobile laboratories, emergency response to a possible biological warfare threat, microbiology laboratories and environmental monitoring. The handheld biological detection system will be capable of rapidly quantifying the presence of extremely low concentrations of any biological agent in a short amount of time.