Multiplexed open circuit potential biosensing instrumentation testbed

Lai Wong, Mohamed Aziz, Pedro Estrela

Research output: Contribution to conferencePosterpeer-review


A detailed understanding of complex biological systems requires information about the functional state of proteins, which perform the bulk of work in the cell. Proteomics currently plays a major role in many areas of biomedicine, such as the identification of cancer biomarkers. The ability to directly interrogate protein interactions is therefore of major importance. In particular, label-free high throughput protein analysis methods allowing quantitative detection are highly desirable. Field-effect devices are promising candidates for the development of inexpensive microarrays associated with portable instrumentation. These stable semiconductor devices measure variations in the open circuit potential (OCP) that occur at the metal gate interface when the charge density and distribution of the immobilised biolayer changes upon interaction with a bioconjugate. We here report on the parallel electrical detection of protein interactions using direct multiplexed OCP variation measurements. The OCP was measured in real-time using an ultra-low input bias current instrumentation amplifier providing an accurate differential measurement of voltage. An array of sensor inputs is switched in high speed via a multiplexer addressed by a microcontroller. The microcontroller converts the OCP differential measurements from analog to digital, displays real-time information on a LCD display, and transfers the captured data by User Datagram Protocol (UDP) / Transmission Control Protocol (TCP) through a WiFi module to other devices. A fully automated and accurate measurement system is hence achieved with direct computer interface for logging and analysis of the data. Apple Push Notification has also been incorporated to notify users’ iOS devices of the measurement status. The present work shows that high-throughput label-free electrical detection of protein interactions can be achieved by direct detection of the OCP with suitable multiplexed instrumentation.
Original languageEnglish
Publication statusPublished - 2011
EventElectrochem 2011 - Bath
Duration: 5 Sept 20116 Sept 2011


ConferenceElectrochem 2011


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