A Pixel Charge Sensor for Biological Processes

Abstract

Sensors with micro-structures have played an important role in the studies of chemical/biological processes, and are at the heart of lab-on-a-chip devices. Notable examples are Micro-Electro-Mechanical-Systems (MEMS) and microfluidic devices.In addition to chemical content/concentration changes, chemical/biological processes often result in charge creation, neutralization and redistribution. We will present a device that can study these tiny charge changes in the system, in a continuous-time fashion with high spatial resolution, which is complementary to existing techniques and has rarely been studied.The recently developed direct charge sensor, Topmetal, originated from nuclear/particle physics, can sense tiny changes in the amount and the spatial distribution of charges as small as tens of electrons at the proximity of its surface. It is also highly pixelated to have a pitch size of 80um. The combination of fine granularity and high change sensitive makes the sensor capable of observing many biological processes involving charge at a mesoscopic length scale that are previously impossible to observe.