Field-effect transistors have been widely demonstrated for protein detection due to their extremely high sensitivity, label-free detection, tiny size and the potential to integrate with electronic devices for personal use. However, several problems, including the materials stability, severe charge-screening effect in high salt clinical samples, and electric isolation between fluids and metal interconnect for miniaturized FETs, need to be solved prior to the application for medical use.
In order to allow people to monitor the risk of disease by themselves timely, the sensor and the readout device need to be small, portable, cheap, and easy to operate. The detection has to be quick and accurate. In this presentation, a new methodology that can overcome severe charge-screening effect for FET-biosensors will be presented. Furthermore, a new miniaturized FET-sensor package and a handheld device with readout circuits were demonstrated with clinical whole blood samples for acute myocardial infarction (AMI) and chronic heart failure (CHF), without any sample purification procedure. The test takes only 5 mins and one drop of whole blood. The same methodology is also used for heavy metal ion detection, which shows sensitivity higher than that of the ideal Nernst limit. Systematic investigation indicates the high sensitivity driven by the high field-modulated electrolyte-gated FET sensors. This sensor and the device are able to allow people to monitor their health and food at anytime and anywhere.