This research team is further developing a platform for electrochemical based human bio-sensing. Past work by this research group has demonstrated the ability to monitor the rate of cholesterol extraction from the cell plasma membrane at cholesterol oxidase modified microelectrodes positioned in contact with the cell surface. The electrode creates a local demand for cholesterol by enzymatic consumption and the flux of cholesterol to the electrode is measured. Studies at single cells and at mouse tissues show that the cholesterol efflux rate is elevated at cystic fibrosis samples relative to wild-type controls. In extending the measurement to human subjects, a double potential pulse data acquisition method was demonstrated where hydrogen peroxide from enzymatic cholesterol oxidation is allowed to accumulate prior to oxidation by potential pulse. A second pulse provides a unique background that is subtracted for evaluation of the amount of hydrogen peroxide. To increase signal to noise so that human measurements may be conducted without a faraday cage, micro/nano sensor chips have been produced that are composed of an array of separated, micron-sized regions containing immobilized enzyme as well as nano-platinum electrodes for oxidation of hydrogen peroxide. Characterization and performance of the sensor chips will be discussed.