Abstract
The glass-based LTPS (low temperature polysilicon) TFT (thin-film transistor) process, as widely known for making liquid crystal displays, is utilized for the first time to make CMOS capacitive sensors for dopamine detection. Dopamine plays important roles in human behavior, cognition, and motor activity. The interface capacitance change, after its binding with 4-carboxyphenylboronic acid (CPBA), was detected by interdigitated microelectrodes and integrated sensing circuits. Three sensor designs showed measured sensitivities of -3.9 fF/mM, -5.4 fF/mM, and -7.2 fF/mM, respectively. The minimum detectable capacitance changes were 12.7 aF, 14.7 aF, and 13.5 aF, equivalent to detectable dopamine concentrations of 3.2 μM, 2.7 μM, and 1.9 μM, respectively. © 2011 IEEE.