In vitro evaluation of a closed-loop feedback system for dopamine concentration control

Abstract

Introduction: It is well known that Parkinson's disease is related to a deficit of dopamine (DA) in the region of the brain called the corpus striatum. The aim of this work is to demonstrate the possibility of in vitro closedloop control of the DA concentration levels. Methods: By applying the electrochemical technique of fast scan cyclic voltammetry (FSCV), the measured values were compared with previously selected ones, and the system made decisions to control infusion pumps by dynamically adjusting the DA concentration in a continuous flow injection cell. Low-cost hardware was used for the acquisition and control signals (Arduino board), whereas for processing the collected data, graphical programming software (LabView) was used. Results: The resolution of the system was approximately 0.4 µmol/L, with a time correction of the concentration adjustable between 1 and 90 seconds. The system allowed control of the DA concentration between 1 and 10 µmol/L with an error of approximately +/-0.8 µmol/L. Conclusion: Although designed to control the DA concentration, the system could be used to control, within the range of the developed FSCV, the concentration of other substances or to turn on brain stimulators. These results encourage the possibility of using the system in clinical studies (in vivo).

Freezing of gait: Promising avenues for future treatment

“…Closed-looped approaches for on-demand dopamine administration also have potential to reduce motor fluctuations and off state freezing, much like existing insulin devices for treating Type I diabetes that tailor dosage according to real-time sensor glucose concentration in order to maximize benefits and minimize sideeffects [16]. Indeed, a prototype that uses the electrochemical technique of fast scan cyclic voltammetry to measure dopamine levels in vitro and control dopamine infusion pumps has already been developed [17] V . Also, a 'neurochemostat' for closed-loop regulation of electrically evoked brain dopamine release in anesthetized rats has been developed [18] V .…”

An investigation into closed-loop treatment of neurological disorders based on sensing mitochondrial dysfunction

“…A number of research studies have identified these advantages, and investigated FSCV for use as the sensor portion in a closed-loop control system. de Araujo CE, Abatti PJ, Da Cunha C, et al [ 147 ], Chang S-Y, Kimble CJ, Kim I, et al [ 148 ], and Bozorgzadeh B, Schuweiler DR, Bobak MJ, et al [ 149 ] all describe closed-loop control systems which use FSCV as the sensing element. However, in all of these cases the sensing target is dopamine release.…”

“…de Araujo CE, Abatti PJ, Da Cunha C, et al [ 147 ] described a FSCV based system which allows for control over dopamine concentration in-vitro. This system uses a number of Arduino-based prototyping boards as the hardware for the FSCV signal production and measurement acquisition while using LabView (National Instruments) on a host-computer for the controller.…”

“…The effector used in this study was a syringe pump which increased the amount of dopamine in the system. The control algorithm used in this system is not explicitly stated, however, the authors do mention that the control is able to control the analyte concentration to within +/− 0.8 μmol/L range with an oscillation period of approximately 80s, indicating the system used is likely some form of PID control [ 147 ]. The key disadvantage of this system is that it requires a host-computer to operate, and the control is operated through the Lab-View software which severely limits the potential for use of this system in-vivo.…”