Partially Functional Electrode Modifications for Rapid Detection of Dopamine in Urine

Abstract

Designing functional materials as electrode coatings to transduce high-quality information about redox molecules in biofluids is crucial for developing the next-generation medical devices. Rapidly analyzing the neurotransmitter dopamine (DA) urinary levels can enable point-of-care testing for neuroendocrine tumors. A novel sensing electrodes array modified with biopolymer chitosan and electrocatalytic carbon nanotube films that can generate crossreactive electrochemical signals from complex biofluids, such as undiluted urine, is presented. By generating cross-reactive signals, the feasibility of quantifying DA levels from unprocessed urine samples is demonstrated. The films' electrochemical activity is characterized and modeled the additive effect of the main redox interferants in urine (norepinephrine and uric acid) on the generated electrochemical signals that overlap and mask the electrochemical signature of DA. Finally, the feasibility of successfully quantifying urinary DA levels is demonstrated by investigating two calibration approaches: 1) using a synthetic solution (1.15 µm root mean squared error (RMSE) and 4.2 µm limitof-detection (LoD) values), and 2) directly using the urine samples (2.5 µm RMSE and 9.3 µm LoD values). The outcome of this work will enhance the understanding of the overlapping and masking electrochemical signatures and their interactions with functional materials, providing better analytical tools to differentiate redox molecules in highly complex biofluids.

Superhydrophilic edge-rich graphene for the simultaneous and disposable sensing of dopamine, ascorbic acid, and uric acid

“…Firstly, it is still a great challenge to distinguish the coexistence of DA, AA and UA in a biological environment due to their overlapping voltammetric response. 14,15 Secondly, the reusability of the sensing electrode is dramatically affected by both chemical (e.g., non-specific proteins) and electrochemical (e.g., redox active molecules) surface fouling. 16,17 To address these issues, research studies have been focused on electrode materials, which are expected to enhance electrontransfer kinetics to overcome the poor selectivity of DA, AA and UA.…”

Actualities in immunological markers and electrochemical sensors for determination of dopamine and its metabolites in psychotic disorders (Review)

“…Using a sensor array consisting of gold electrodes unmodified and modified with cross-reactive films, i.e., the biopolymer chitosan and chitosan-CNTs, and two chemometric approaches (artificial neural network and a partial least squares regression), Shukla et al (91) predicted DA levels in undiluted and untreated urine samples, eliminating the effects of the main interfering redox species, norepinephrine (NEP) and uric acid (UA). The disadvantage of the systems is related to the electrode surface contamination during the analysis.…”

Immobilized Molecules’ Impact on the Efficacy of Nanocarbon Organic Sensors for Ultralow Dopamine Detection in Biofluids

“…[ 63,64 ] Furthermore, probing the DA at the nanomolar level in undiluted waste biofluids such as sweat and urine is still in the pipeline. [ 12,29,65 ] The majority of previous studies have mainly focused on lowering the detection limit rather than other pivotal aspects, such as simplicity, and a qualitative understanding of the precise correlation between the analyte and material followed by electrical transduction at the molecular level. All the reasons stated above have hampered the commercialization of electrochemical point‐of‐care DA sensors.…”

“…[20,21] Therefore, numerous materials based on electrochemical sensing technologies have been developed so far. [22][23][24][25][26][27][28][29][30][31][32][33] Ultrasensitive electrochemical sensors with DA detection limit in femtomolar have recently been reported, but their use for developing the sensing probes (for POC units) remains limited due to the use of precious metals, aptamers, enzymes, composites, and highly processed carbon-based derivatives. [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] Since sensors based solely on 2D carbon derivatives perform better than metalbased/hybrid/polymer composite(s) in terms of compatibility, simplicity, and affordability, their use is generally promoted in electrochemical biosensing technologies.…”

“…[63,64] Furthermore, probing the DA at the nanomolar level in undiluted waste biofluids such as sweat and urine is still in the pipeline. [12,29,65] The majority of previous studies have mainly Dopamine (DA) is a key neurotransmitter that regulates many behaviors and physical functions in the human body. Therefore, there is a significant technological demand for an affordable point-of-care (POC) device to monitor low DA levels up to 10 −12 m in human biofluids.…”