Carbon nanospheres modified with WO2-NaxWO3 nanoparticles for highly sensitive electrochemical detection of dopamine

Biochemical Sensors for Personalized Therapy in Parkinson's Disease: Where We Stand

Since its first introduction, levodopa has remained the cornerstone treatment for Parkinson's disease. However, as the disease advances, the therapeutic window for levodopa narrows, leading to motor complications like fluctuations and dyskinesias. Clinicians face challenges in optimizing daily therapeutic regimens, particularly in advanced stages, due to the lack of quantitative biomarkers for continuous motor monitoring. Biochemical sensing of levodopa offers a promising approach for real-time therapeutic feedback, potentially sustaining an optimal motor state throughout the day. These sensors vary in invasiveness, encompassing techniques like microdialysis, electrochemical non-enzymatic sensing, and enzymatic approaches. Electrochemical sensing, including wearable solutions that utilize reverse iontophoresis and microneedles, is notable for its potential in non-invasive or minimally invasive monitoring. Point-of-care devices and standard electrochemical cells demonstrate superior performance compared to wearable solutions; however, this comes at the cost of wearability. As a result, they are better suited for clinical use. The integration of nanomaterials such as carbon nanotubes, metal-organic frameworks, and graphene has significantly enhanced sensor sensitivity, selectivity, and detection performance. This framework paves the way for accurate, continuous monitoring of levodopa and its metabolites in biofluids such as sweat and interstitial fluid, aiding real-time motor performance assessment in Parkinson's disease. This review highlights recent advancements in biochemical sensing for levodopa and catecholamine monitoring, exploring emerging technologies and their potential role in developing closed-loop therapy for Parkinson's disease.

Willow catkin template synthesis of NiS@NSC hollow tubes for highly sensitive dual-function electrochemical detection of acetaminophen and Cu2

Public health and environmental well-being have become increasingly threatened by the contamination of pharmaceuticals and heavy metal ions. This study focuses on addressing this critical issue by developing a novel electrochemical sensor for the dual-functional detection of acetaminophen (AP) and Cu2+. Utilizing willow catkins as a biomass template, a hollow tubular NiS@NSC composite was prepared by simple nickel salt impregnation combined with calcination and sulfurization. A highly sensitive dual-functional electrochemical sensor was thus constructed that can detect both acetaminophen (AP) and Cu2+. By examining its electrochemical properties, the sensor achieves an impressive detection limit of 1.33 pM for AP, with a linear range of 4.00 pM ~ 0.15 mM. The sensor can also detect Cu2+, with a detection limit of 1.04 µM, and a linear range of 3.13 µM ~ 0.66 mM. The sensor also exhibits strong resistance to interference, and good repeatability and stability. In addition, the sensor has demonstrated good performance in actual sample analysis, including the detection of AP in serum and Cu2+ in wastewater. This excellent electrochemical sensing performance is mainly attributed to the synergistic effect of its unique tubular structure and highly conductive N, S co-doped carbon. This results in the sensor exhibiting minimal charge transfer resistance, an extensive electrochemically active surface area, and a high density of active sites.

Carbon Nanomaterials-Based Novel Hybrid Platforms for Electrochemical Sensor Applications in Drug Analysis

Nowadays, the rapid improvements in the medical and pharmaceutical fields increase the diversity and use of drugs. However, problems such as the use of multiple or combined drugs in the treatment of diseases and insensible use of over-the-counter drugs have caused concerns about the side-effect profiles and therapeutic ranges of drugs and environmental contamination and pollution problems due to pharmaceuticals waste. Therefore, the analysis of drugs in various media such as biological, pharmaceutical, and environmental samples is an important topic of discussion. Electrochemical methods are advantageous for sensor applications due to their easy application, low cost, versatility, high sensitivity, and environmentally-friendliness. Carbon nanomaterials such as diamond-like carbon thin films, carbon nanotubes, carbon nanofibers, graphene oxide, and nanodiamonds are used to enhance the performance of the electrochemical sensors with catalytic effects. To further improve this effect, it is aimed to create hybrid platforms by using different carbon nanomaterials together or with materials such as conductive polymers and ionic liquids. In this review, the most used carbon nanoforms will be evaluated in terms of electrochemical characterizations and physicochemical properties. Furthermore, the effect of hybrid platforms developed in the most recent studies on electrochemical sensors will be examined and evaluated in terms of drug analysis studies in the last five years.

Advanced Nanomaterials-Based Electrochemical Biosensors for Catecholamines Detection: Challenges and Trends

Catecholamines, including dopamine, epinephrine, and norepinephrine, are considered one of the most crucial subgroups of neurotransmitters in the central nervous system (CNS), in which they act at the brain's highest levels of mental function and play key roles in neurological disorders. Accordingly, the analysis of such catecholamines in biological samples has shown a great interest in clinical and pharmaceutical importance toward the early diagnosis of neurological diseases such as Epilepsy, Parkinson, and Alzheimer diseases. As promising routes for the real-time monitoring of catecholamine neurotransmitters, optical and electrochemical biosensors have been widely adopted and perceived as a dramatically accelerating development in the last decade. Therefore, this review aims to provide a comprehensive overview on the recent advances and main challenges in catecholamines biosensors. Particular emphasis is given to electrochemical biosensors, reviewing their sensing mechanism and the unique characteristics brought by the emergence of nanotechnology. Based on specific biosensors' performance metrics, multiple perspectives on the therapeutic use of nanomaterial for catecholamines analysis and future development trends are also summarized.

Plasmonic Refractive Index Sensor Enhanced with Chitosan/Au Bilayer Thin Film for Dopamine Detection

Surface plasmonic sensors have received considerable attention, found extensive applications, and outperformed conventional optical sensors. In this work, biopolymer chitosan (CS) was used to prepare the bilayer structure (CS/Au) of a plasmonic refractive index sensor for dopamine (DA) detection. The sensing characteristics of the developed plasmonic sensor were evaluated. Increasing DA concentrations significantly shifted the SPR dips. The sensor exhibited stability and a refractive index sensitivity of 8.850°/RIU in the linear range 0.1 nM to 1 µM with a detection limit of 0.007 nM and affinity constant of 1.383 × 108 M-1. The refractive index and thickness of the CS/Au structure were measured simultaneously by fitting the obtained experimental findings to theoretical data based on Fresnel equations. The fitting yielded the refractive index values n (1.5350 ± 0.0001) and k (0.0150 ± 0.0001) for the CS layer contacting 0.1 nM of DA, and the thickness, d was (15.00 ± 0.01) nm. Then, both n and d values increased by increasing DA concentrations. In addition, the changes in the FTIR spectrum and the variations in sensor surface roughness and structure obtained by AFM analysis confirmed DA adsorption on the sensing layer. Based on these observations, CS/Au bilayer has enhanced the performance of this plasmonic sensor, which showed promising importance as a simple, low-cost, and reliable platform for DA sensing.