Dual-Functionalization Device for Therapy through Dopamine Release and Monitoring

A dual-functional device is fabricated to release progressively dopamine (DA) from a biohydrogel under real-time monitoring via electrochemical detection. For this purpose, a poly-gamma-glutamic acid biohydrogel is assembled with a poly(3,4-ethylenedioxythiophene) (PEDOT) layer, previously deposited onto a screen printed electrode. The biohydrogel is formulated to achieve dimensional stability and maximum DA-loading capacity. Conditions for DA-loading are influenced by the oxidation of the neurotransmitter in acid environments and the poor resistance of PEDOT to the lyophilization. The performance of the device is proved in a medium with the physiological pH of blood and the cerebrospinal fluid. The progressive release of DA is successfully monitored by the device, the limit of detection and sensitivity of the integrated sensor being 450 x 10(-9) M and 8 x 10(-5) mA mu m(-1), respectively. The effect of electrochemical stimulation in the kinetics of the DA release is also investigated applying potential ramps in cyclic phase to alter the biohydrogel morphology.