Wearable Electrochemical Sensors in Parkinson’s Disease

Abstract

Parkinson’s disease (PD) is a neurodegenerative disorder associated with widespread aggregation of α-synuclein and dopaminergic neuronal loss in the substantia nigra pars compacta. As a result, striatal dopaminergic denervation leads to functional changes in the cortico-basal-ganglia-thalamo-cortical loop, which in turn cause most of the parkinsonian signs and symptoms. Despite tremendous advances in the field in the last two decades, the overall management (i.e., diagnosis and follow-up) of patients with PD remains largely based on clinical procedures. Accordingly, a relevant advance in the field would require the development of innovative biomarkers for PD. Recently, the development of miniaturized electrochemical sensors has opened new opportunities in the clinical management of PD thanks to wearable devices able to detect specific biological molecules from various body fluids. We here first summarize the main wearable electrochemical technologies currently available and their possible use as medical devices. Then, we critically discuss the possible strengths and weaknesses of wearable electrochemical devices in the management of chronic diseases including PD. Finally, we speculate about possible future applications of wearable electrochemical sensors in PD, such as the attractive opportunity for personalized closed-loop therapeutic approaches.

An Amperometric Biosensor Based on a Bilayer of Electrodeposited Graphene Oxide and Co-Crosslinked Tyrosinase for L-Dopa Detection in Untreated Human Plasma

“…The proposed biosensor allows achieving linear L-DOPA responses from 1 up to 190 µM, which seems better than many tyrosinase devices (0–20 µM [ 23 ], 5–30 µM [ 22 ], 0.8–22.3 µM [ 20 ]). The presence of the compact outer layer slows down the diffusion of the analyte and its oxidation product, increasing linearity.…”

“…Figure 3 shows the linear range of a typical calibration curve of the modified electrode acquired upon the addition of aliquots of a stock L-Dopa solution in an air-saturated buffer. The proposed biosensor allows achieving linear L-DOPA responses from 1 up to 190 µM, which seems better than many tyrosinase devices (0-20 µM [23], 5-30 µM [22], 0.8-22.3 µM [20]). The presence of the compact outer layer slows down the diffusion of the analyte and its oxidation product, increasing linearity.…”

“…To date, few enzyme-based biosensors are reported making use of tyrosinase for biorecognition of L-Dopa [ 18 , 19 , 20 , 21 , 22 , 23 ]. Among these, potentially “wearable” biosensors have been proposed made on microneedles and tested in vitro on artificial interstitial fluid [ 21 ] and bovine serum [ 23 ] and in vivo in rat abdominal cavities [ 23 ].…”

“…To date, few enzyme-based biosensors are reported making use of tyrosinase for biorecognition of L-Dopa [ 18 , 19 , 20 , 21 , 22 , 23 ]. Among these, potentially “wearable” biosensors have been proposed made on microneedles and tested in vitro on artificial interstitial fluid [ 21 ] and bovine serum [ 23 ] and in vivo in rat abdominal cavities [ 23 ]. In order to improve selectivity towards L-Dopa, a dual sensing platform was adopted based on parallel, simultaneous, and independent enzymatic and nonenzymatic electrochemical detection.…”

Biopolymer-protected graphene-Fe3O4 nanocomposite based wearable microneedle sensor: toward real-time continuous monitoring of dopamine

“…On a circular microneedle patch, there are four hollow microneedles distributed. The diameter of each hollow microneedle is 0.5 mm which is placed at a 10 mm spacing 46 These were split into two working electrodes (WE), one counter electrode (CE), and one reference electrode (RE). A 5 mm long Ag wire is fitted into a microneedle space which will be acting as a RE.…”