An Updated Review on Electrochemical Nanobiosensors for Neurotransmitter Detection

Carbon microelectrodes for the measurement of neurotransmitters with fast-scan cyclic voltammetry: methodology and applications

Carbon microelectrodes (CMEs) have emerged as pivotal tools in the field of neurochemical sensing, enabling precise, real-time monitoring of neurotransmitters in both research and clinical contexts. The current review explores the design, fabrication, and application of CMEs, emphasizing recent advancements in material science and electrochemical techniques that enhance their sensitivity, selectivity, and biocompatibility. Innovations such as the incorporation of nanomaterials, including graphene and carbon nanotubes, and the adoption of advanced fabrication methods like three-dimensional (3D) printing and chemical vapor deposition, are discussed in detail. These developments have led to significant improvements in electrode performance, the reduction of biofouling and interferants, while enabling the detection of low concentrations of neurochemicals in complex biological systems. This review further highlights the potential of CMEs to address clinical challenges such as diagnosing and monitoring neurological disorders such as Parkinson's Disease and depression. By integrating advanced surface modifications, polymer coatings, and method development strategies, CMEs demonstrate high durability, reduced fouling, and enhanced specificity. Despite these advancements, challenges remain related to long-term in vivo stability, batch fabrication, and reproducibility, thus necessitating further research and optimization. This review highlights the transformative potential of CMEs in both research and therapeutic applications, providing a comprehensive overview of their current state and future directions. By addressing existing limitations and leveraging emerging technologies, CMEs have the potential to further enhance neurochemical sensing and contribute to breakthroughs in neuroscience and biomedical science.

Nanomaterial sensors for enhanced detection of serotonin

The detection of serotonin (5-HT), a critical neurotransmitter, has garnered significant attention in biosensor research because of its pivotal role in neurological and physiological processes. This narrative review highlights advancements in nanomaterial-based sensors designed to increase the sensitivity, specificity, and functionality of serotonin detection. Carbon-based nanomaterials, including carbon nanotubes (CNTs), graphene derivatives, and carbon nanofibers (CNFs), have demonstrated remarkable potential owing to their large surface area, superior electrical conductivity, and biocompatibility. These materials enable rapid electron transfer and selective serotonin adsorption, making them integral to electrochemical and wearable sensor technologies. Emerging technologies, including field-effect transistors (FETs), magnetoelastic biosensors, and molecularly imprinted polymers (MIPs), have demonstrated ultralow detection limits and real-time monitoring capabilities, suggesting promising applications for clinical diagnostics and personalized healthcare. Metal-based sensors, which utilize nanoparticles of gold, silver, and other metals, have also shown exceptional performance in serotonin detection through enhanced electrocatalysis and optical properties. This review underscores the transformative potential of nanomaterial-based sensors in serotonin detection, emphasizing their role in advancing neuroscience research, disease diagnostics, and therapeutic monitoring.

Emerging biophysical techniques for probing synaptic transmission in neurodegenerative disorders

Plethora of research has shed light on the critical role of synaptic dysfunction in various neurodegenerative disorders (NDDs), including Alzheimer's disease (AD), Parkinson's disease (PD), Amyotrophic lateral sclerosis (ALS), and Huntington's disease (HD). Synapses, the fundamental units for neural communication in the brain, are highly vulnerable to pathological conditions and are central to the progression of neurological diseases. The presynaptic terminal, a key component of synapses responsible for neurotransmitter release and synaptic communication, undergoes structural and functional alterations in these disorders. Understanding synaptic transmission abnormalities is crucial for unravelling the pathophysiological mechanisms underlying neurodegeneration. In the quest to probe synaptic transmission in NDDs, emerging biophysical techniques play a pivotal role. These advanced methods offer insights into the structural and functional changes occurring at nerve terminals in conditions like AD, PD, HD & ALS. By investigating synaptic plasticity and alterations in neurotransmitter release dynamics, researchers can uncover valuable information about disease progression and potential therapeutic targets. The review articles highlighted provide a comprehensive overview of how synaptic vulnerability and pathology are shared mechanisms across a spectrum of neurological disorders. In major neurodegenerative diseases, synaptic dysfunction is a common thread linking these conditions. The intricate molecular machinery involved in neurotransmitter release, synaptic vesicle dynamics, and presynaptic protein regulation are key areas of focus for understanding synaptic alterations in neurodegenerative diseases.

Laser-Induced Metal-Organic Framework-Derived Flexible Electrodes for Electrochemical Sensing

The successful development of a metal-organic framework (MOF)-derived Co/Co3O4/C core-shell composite integrated into laser-induced graphitic (LIG) carbon electrodes for electrochemical sensing is reported. The sensors are fabricated via a direct laser scribing technique using a UV laser (355 nm wavelength) to induce the photothermolysis of rationally selected ZIF-67 into the LIG matrix. Electrochemical characterization reveals that the incorporation of the laser-scribed ZIF-67-derived composite on the electrode surface reduces the impedance more than 100 times compared with bare LIG sensors. Comprehensive morphological, structural, and chemical analyses confirm the formation of porous LIG from the laser irradiation of polyimide, while the LIG+ZIF-67-derived composites feature size-controlled and uniformly distributed Co/Co3O4 core/shell nanoparticles (NPs) in the semihollow wasp-nest-like carbon matrix from photothermal decomposition of ZIF-67, embedded within the LIG electrode area. The high surface area and porosity of this ZIF-67-derived nitrogen-rich carbon facilitate charge transfer processes, whereas size-controlled Co/Co3O4 core/shell NPs offer accessible electrochemical active sites, making these LIG+ZIF-67-derived composite-based sensors promising materials for applications requiring high charge injection capability and low electrode/electrolyte interface impedance. The PI+Z67L sensor exhibited a 400 times higher specific capacitance (2.4 mF cm-2) compared to the PIL sensor (6 μF cm-2). This laser scribing approach enables the rapid and cost-effective fabrication of high-performance electrochemical sensors enhanced by the integration of tailored MOF-derived composites.

Synthesis of Palladium Nanowires on Flagella Template for Electrochemical Biosensor Detection of microRNA-21

In recent years, the use of bacterial flagella as biomimetic templates has gained increasing attention in nanomaterial synthesis due to their unique structural and functional properties. In this study, we optimized the flagella extraction method and achieved a high concentration of flagella solution. Flagella were isolated from Escherichia coli. Surface characterization revealed that the flagella had abundant functional groups, such as amino and carboxyl groups, which can serve as nucleation sites for the controlled nucleation and growth of metal nanomaterials. Using bacterial flagella as a template, we synthesized one-dimensional palladium nanowires (Fla-Pd NWs). The results of morphological and phase analyses showed that the synthesized palladium nanoparticles were uniformly and densely distributed on the surface of the flagella. Moreover, the Fla-Pd nanowires exhibited superior electrocatalytic activity, which was applied to develop an electrochemical biosensor. This biosensor was used to detect the early breast cancer biomarker microRNA-21 and exhibited a linear range of 0.66-1.98 µmol/L and a detection limit of 0.78 µmol/L. The method demonstrated high selectivity and reusability, making it a promising strategy for early cancer diagnosis.

Platinum nanowires/MXene nanosheets/porous carbon ternary nanocomposites for in situ monitoring of dopamine released from neuronal cells

Dopamine is an important neurotransmitter in the body and closely related to many neurodegenerative diseases. Therefore, the detection of dopamine is of great significance for the diagnosis and treatment of diseases, screening of drugs and unraveling of relevant pathogenic mechanisms. However, the low concentration of dopamine in the body and the complexity of the matrix make the accurate detection of dopamine challenging. Herein, an electrochemical sensor is constructed based on ternary nanocomposites consisting of one-dimensional Pt nanowires, two-dimensional MXene nanosheets, and three-dimensional porous carbon. The Pt nanowires exhibit excellent catalytic activity due to the abundant grain boundaries and highly undercoordinated atoms; MXene nanosheets not only facilitate the growth of Pt nanowires, but also enhance the electrical conductivity and hydrophilicity; and the porous carbon helps induce significant adsorption of dopamine on the electrode surface. In electrochemical tests, the ternary nanocomposite-based sensor achieves an ultra-sensitive detection of dopamine (S/N = 3) with a low limit of detection (LOD) of 28 nM, satisfactory selectivity and excellent stability. Furthermore, the sensor can be used for the detection of dopamine in serum and in situ monitoring of dopamine release from PC12 cells. Such a highly sensitive nanocomposite sensor can be exploited for in situ monitoring of important neurotransmitters at the cellular level, which is of great significance for related drug screening and mechanistic studies.

Recent advances in two-dimensional materials for the diagnosis and treatment of neurodegenerative diseases

With the size of the aging population increasing worldwide, the effective diagnosis and treatment of neurodegenerative diseases (NDDs) has become more important. Two-dimensional (2D) materials offer specific advantages for the diagnosis and treatment of NDDs due to their high sensitivity, selectivity, stability, and biocompatibility, as well as their excellent physical and chemical characteristics. As such, 2D materials offer a promising avenue for the development of highly sensitive, selective, and biocompatible theragnostics. This review provides an interdisciplinary overview of advanced 2D materials and their use in biosensors, drug delivery, and tissue engineering/regenerative medicine for the diagnosis and/or treatment of NDDs. The development of 2D material-based biosensors has enabled the early detection and monitoring of NDDs via the precise detection of biomarkers or biological changes, while 2D material-based drug delivery systems offer the targeted and controlled release of therapeutics to the brain, crossing the blood-brain barrier and enhancing treatment effectiveness. In addition, when used in tissue engineering and regenerative medicine, 2D materials facilitate cell growth, differentiation, and tissue regeneration to restore neuronal functions and repair damaged neural networks. Overall, 2D materials show great promise for use in the advanced treatment of NDDs, thus improving the quality of life for patients in an aging population.

Treatments and regulatory mechanisms of acoustic stimuli on mood disorders and neurological diseases

Acoustic stimuli such as music or ambient noise can significantly affect physiological and psychological health in humans. We here summarize positive effects of music therapy in premature infant distress regulation, performance enhancement, sleep quality control, and treatment of mental disorders. Specifically, music therapy exhibits promising effects on treatment of neurological disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD). We also highlight regulatory mechanisms by which auditory intervention affects an organism, encompassing modulation of immune responses, gene expression, neurotransmitter regulation and neural circuitry. As a safe, cost-effective and non-invasive intervention, music therapy offers substantial potential in treating a variety of neurological conditions.