Prunella vulgaris-phytosynthesized platinum nanoparticles: Insights into nanozymatic activity for H2O2 and glutamate detection and antioxidant capacity

Artificial nanozymes (enzyme-mimics), specifically metallic nanomaterials, have garnered significant attention recently due to their reduced preparation cost and enhanced stability in a wide range of environments. The present investigation highlights, for the first time, a straightforward green synthesis of biogenic platinum nanoparticles (PtNPs) from a natural resource, namely Prunella vulgaris (Pr). To demonstrate the effectiveness of the phytochemical extract as an effective reducing agent, the PtNPs were characterized by various techniques such as UV-vis spectroscopy, High-resolution Transmission electron microscopy (HR-TEM), zeta-potential analysis, Fourier-transform infrared spectroscopy (FTIR), and Energy dispersive spectroscopy (EDS). The formation of PtNPs with narrow size distribution was verified. Surface decoration of PtNPs was demonstrated with multitudinous functional groups springing from the herbal extract. To demonstrate their use as viable nanozymes, the peroxidase-like activity of Pr/PtNPs was evaluated through a colorimetric assay. Highly sensitive visual detection of H2O2 with discrete linear ranges and a low detection limit of 3.43 μM was demonstrated. Additionally, peroxidase-like catalytic activity was leveraged to develop a colorimetric platform to quantify glutamate biomarker levels with a high degree of selectivity, the limit of detection (LOD) being 7.00 μM. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) test was used to explore the scavenging nature of the PtNPs via the degradation of DPPH. Overall, the colorimetric assay developed using the Pr/PtNP nanozymes in this work could be used in a broad spectrum of applications, ranging from biomedicine and food science to environmental monitoring.

Photonic Solutions for Challenges in Sensing

Sensing technologies support timely and critical decisions to save precious resources in healthcare, veterinary care, food safety, and environmental protection. However, the design of sensors demands strict technical characteristics for real-world applications. In this Viewpoint, we discuss the main challenges to tackle in the sensing field and how photonics represents a valuable tool in this sphere.

Nanostructured Metal Oxide-Based Electrochemical Biosensors in Medical Diagnosis

Nanostructured metal oxides (NMOs) provide electrical properties such as high surface-to-volume ratio, reaction activity, and good adsorption strength. Furthermore, they serve as a conductive substrate for the immobilization of biomolecules, exhibiting notable biological activity. Capitalizing on these characteristics, they find utility in the development of various electrochemical biosensing devices, elevating the sensitivity and selectivity of such diagnostic platforms. In this review, different types of NMOs, including zinc oxide (ZnO), titanium dioxide (TiO2), iron (II, III) oxide (Fe3O4), nickel oxide (NiO), and copper oxide (CuO); their synthesis methods; and how they can be integrated into biosensors used for medical diagnosis are examined. It also includes a detailed table for the last 10 years covering the morphologies, analysis techniques, analytes, and analytical performances of electrochemical biosensors developed for medical diagnosis.

Recent advances in the biosynthesis and industrial biotechnology of Gamma-amino butyric acid

GABA (Gamma-aminobutyric acid), a crucial neurotransmitter in the central nervous system, has gained significant attention in recent years due to its extensive benefits for human health. The review focused on recent advances in the biosynthesis and production of GABA. To begin with, the investigation evaluates GABA-producing strains and metabolic pathways, focusing on microbial sources such as Lactic Acid Bacteria, Escherichia coli, and Corynebacterium glutamicum. The metabolic pathways of GABA are elaborated upon, including the GABA shunt and critical enzymes involved in its synthesis. Next, strategies to enhance microbial GABA production are discussed, including optimization of fermentation factors, different fermentation methods such as co-culture strategy and two-step fermentation, and modification of the GABA metabolic pathway. The review also explores methods for determining glutamate (Glu) and GABA levels, emphasizing the importance of accurate quantification. Furthermore, a comprehensive market analysis and prospects are provided, highlighting current trends, potential applications, and challenges in the GABA industry. Overall, this review serves as a valuable resource for researchers and industrialists working on GABA advancements, focusing on its efficient synthesis processes and various applications, and providing novel ideas and approaches to improve GABA yield and quality.

Green synthesized gold nanoparticles and CuO-based nonenzymatic sensor for saliva glucose monitoring

Glucose, essential for brain and muscle functions, requires careful monitoring in diabetes and other chronic disease management. While blood glucose monitoring provides precise information about these diseases, it remains an invasive method. Saliva glucose monitoring could offer an alternative approach, but the glucose concentration in saliva is very low. In this work, we report a simple, low-cost, highly sensitive nonenzymatic electrochemical glucose sensor. We developed this sensor using green synthesized gold nanoparticles (AuNPs) and wet chemical synthesized copper oxide (CuO) nanoparticles on a screen-printed carbon electrode (Au/CuO/SPCE). The sensor's high sensitivity results from dual amplification strategies using AuNPs and CuO nanomaterials, each demonstrating catalytic activity towards glucose. This shows promising potential for saliva glucose monitoring. The AuNPs were synthesized using an Au precursor and orange peel extract (OPE), yielding stable colloidal AuNPs with a mean diameter of about 37 nm, thus eliminating the need for additional capping agents. Under optimal conditions, amperometric tests revealed that the sensor responded linearly to glucose concentrations ranging from 2 μM to 397 μM with a sensitivity of 236.70 μA mM-1 cm-2. Furthermore, the sensor demonstrated excellent reproducibility, stability and high selectivity for glucose in the presence of different biomolecules. We validated the sensor's efficacy by measuring glucose in human saliva, showing its potential for noninvasive glucose monitoring. This research advances the development of point-of-care devices, positioning the sensor as a promising tool for noninvasive glucose monitoring and improved diabetes management.

Highly Efficient Enzyme-Free Glutamate Sensors Using Porous Network Metal-Organic Framework-Ni-NiO-Ni-Carbon Nanocomposites

This study introduces an innovative electrochemical sensor designed to detect glutamate using a nonenzymatic approach. The sensor utilizes a porous network metal-organic framework (Ni-MOF)-NiO-Ni-Carbon nanocomposite (PNM-NiO-Ni-Carbon) as an electrode modifier, which was synthesized and assessed for its effectiveness. Cyclic voltammetry measurements demonstrated that the PNM-NiO-Ni-Carbon nanocomposite, synthesized at 450 °C, displayed remarkable electrocatalytic activity for glutamate oxidation. The linear range for detection spanned from 5 to 960 μmol/L, and the sensor achieved a low detection limit of 320 nmol/L (S/N = 3), which was comparable to previously reported data. Moreover, the sensor exhibited high accuracy and favorable recovery rates when tested with real samples, thus, demonstrating its potential for rapid glutamate detection. The real samples were analyzed using both electrochemical and high-performance liquid chromatography methods, and the results obtained from the two methods did not differ significantly, validating the sensor's excellent practical performance. Based on our findings, the PNM-NiO-Ni-Carbon system exhibits potential for a wide range of biomedical applications.

Integration of Glutamate Dehydrogenase and Nanoporous Gold for Electrochemical Detection of Glutamate

Glutamate, a non-essential amino acid produced by fermentation, plays a significant role in disease diagnosis and food safety. It is important to enable the real-time monitoring of glutamate concentration for human health and nutrition. Due to the challenges in directly performing electrochemical oxidation-reduction reactions of glutamate, this study leverages the synergistic effect of glutamate dehydrogenase (GLDH) and nanoporous gold (NPG) to achieve the indirect and accurate detection of glutamate within the range of 50 to 700 μM by measuring the generated quantity of NADH during the enzymatic reaction. The proposed biosensor demonstrates remarkable performance characteristics, including a detection sensitivity of 1.95 μA mM-1 and a limit of detection (LOD) of 6.82 μM. The anti-interference tests indicate an average recognition error ranging from -3.85% to +2.60%, spiked sample recovery rates between 95% and 105%, and a relative standard deviation (RSD) of less than 4.97% for three replicate experiments. Therefore, the GLDH-NPG/GCE biosensor presented in this work exhibits excellent accuracy and repeatability, providing a novel alternative for rapid glutamate detection. This research contributes significantly to enhancing the precise monitoring of glutamate concentration, thereby offering more effective guidance and control for human health and nutrition.

Research progress of sensors based on molecularly imprinted polymers in analytical and biomedical analysis

Molecularly imprinted polymers (MIPs) have had tremendous impact on biomimetic recognition due to their precise specificity and high affinity comparable to that of antibodies, which has shown the great advantages of easy preparation, good stability and low cost. The combination of MIPs with other analytical technologies can not only achieve rapid extraction and sensitive detection of target compounds, improving the level of analysis, but also achieve precise targeted delivery, in-vivo imaging and other applications. Among them, the recognition mechanism plays a vital role in chemical and biological sensing, while the improvement of the recognition element, such as the addition of new nanomaterials, can greatly improve the analytical performance of the sensor, especially in terms of selectivity. Currently, due to the need for rapid diagnosis and improved sensing properties (such as selectivity, stability, and cost-effectiveness), researchers are investigating new recognition elements and their combinations to improve the recognition capabilities of chemical sensing and bio-sensing. Therefore, this review mainly discusses the design strategies of optical sensors, electrochemical sensors and photoelectric sensors with molecular imprinting technology and their applications in environmental systems, food fields, drug detection and biology including bacteria and viruses.

Flexible, Miniaturized Sensing Probes Inspired by Biofuel Cells for Monitoring Synaptically Released Glutamate in the Mouse Brain

Chemical biomarkers in the central nervous system can provide valuable quantitative measures to gain insight into the etiology and pathogenesis of neurological diseases. Glutamate, one of the most important excitatory neurotransmitters in the brain, has been found to be upregulated in various neurological disorders, such as traumatic brain injury, Alzheimer's disease, stroke, epilepsy, chronic pain, and migraines. However, quantitatively monitoring glutamate release in situ has been challenging. This work presents a novel class of flexible, miniaturized probes inspired by biofuel cells for monitoring synaptically released glutamate in the nervous system. The resulting sensors, with dimensions as low as 50 by 50 μm, can detect real-time changes in glutamate within the biologically relevant concentration range. Experiments exploiting the hippocampal circuit in mice models demonstrate the capability of the sensors in monitoring glutamate release via electrical stimulation using acute brain slices. These advances could aid in basic neuroscience studies and translational engineering, as the sensors provide a diagnostic tool for neurological disorders. Additionally, adapting the biofuel cell design to other neurotransmitters can potentially enable the detailed study of the effect of neurotransmitter dysregulation on neuronal cell signaling pathways and revolutionize neuroscience.

Changes in Brain GABA and Glutamate and Improvements in Physical Functioning Following Intensive Pain Rehabilitation in Youth With Chronic Pain

Intensive interdisciplinary pain treatments (IIPT) have been developed to treat youth with unmanaged chronic pain and functional disability. Dysregulation of metabolites gamma-aminobutyric acid (GABA) and glutamate are thought to play a role in the chronification of pain due to imbalances in inhibition and excitation in adults. Using magnetic resonance spectroscopy (MRS), we investigated the effect of IIPT on GABA and Glx (glutamate + glutamine) in 2 pain-related brain regions: the left posterior insula (LPI) and the anterior cingulate cortex (ACC). Data were collected in 23 youth (mean age = 16.09 ± 1.40, 19 female) at entry and discharge from a hospital-based outpatient IIPT. GABA and Glx were measured using GABA-edited MEGA-PRESS and analyzed using Gannet. Physical measures including a 6-minute walk test were recorded, and patients completed the PLAYSelf Physical Literacy Questionnaire, PROMIS Pain Interference Questionnaire, and Functional Disability Inventory. LPI GABA (P < .05) significantly decreased, but not ACC GABA (P > .05), following IIPT. There were no significant Glx changes (P > .05). The decrease in LPI GABA was associated with increased distance in the 6-minute walk test (P < .001). IIPT may decrease GABAergic inhibitory tone within the LPI, thereby promoting plasticity and contributing to improvements in physical outcomes with IIPT. PERSPECTIVE: Regional GABA changes are associated with a reduction in pain interference and improvement in physical function in youth following intensive pain rehabilitation. GABA may serve as a possible biomarker for IIPT; and may also further aid in the development of IIPT, and other treatments for chronic pain in youth.

Streamlining the interface between electronics and neural systems for bidirectional electrochemical communication

Seamless neural interfaces conjoining neurons and electrochemical devices hold great potential for highly efficient signal transmission across neural systems and the external world. Signal transmission through chemical sensing and stimulation via electrochemistry is remarkable because communication occurs through the same chemical language of neurons. Emerging strategies based on synaptic interfaces, iontronics-based neuromodulation, and improvements in selective neurosensing techniques have been explored to achieve seamless integration and efficient neuro-electronics communication. Synaptic interfaces can directly exchange signals to and from neurons, in a similar manner to that of chemical synapses. Hydrogel-based iontronic chemical delivery devices are operationally compatible with neural systems for improved neuromodulation. In this perspective, we explore developments to improve the interface between neurons and electrodes by targeting neurons or sub-neuronal regions including synapses. Furthermore, recent progress in electrochemical neurosensing and iontronics-based chemical delivery is examined.

Nanomaterials-Based Electrochemical Δ9-THC and CBD Sensors for Chronic Pain

Chronic pain is now included in the designation of chronic diseases, such as cancer, diabetes, and cardiovascular disease, which can impair quality of life and are major causes of death and disability worldwide. Pain can be treated using cannabinoids such as Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD) due to their wide range of therapeutic benefits, particularly as sedatives, analgesics, neuroprotective agents, or anti-cancer medicines. While little is known about the pharmacokinetics of these compounds, there is increasing interest in the scientific understanding of the benefits and clinical applications of cannabinoids. In this review, we study the use of nanomaterial-based electrochemical sensing for detecting Δ9-THC and CBD. We investigate how nanomaterials can be functionalized to obtain highly sensitive and selective electrochemical sensors for detecting Δ9-THC and CBD. Additionally, we discuss the impacts of sensor pretreatment at fixed potentials and physiochemical parameters of the sensing medium, such as pH, on the electrochemical performance of Δ9-THC and CBD sensors. We believe this review will serve as a guideline for developing Δ9-THC and CBD electrochemical sensors for point-of-care applications.

Effect of dendrimer-based interlayers for enzyme immobilization on a model electrochemical sensing system for glutamate

In this paper, we discuss dendrimer usage in enzyme-based electrochemical biosensors, particularly with respect to biomolecule loading on the sensing surface. A novel approach to design bioactive layers with immobilized enzymes for electrochemical biosensors using the surface plasmon resonance (SPR) method in combination with electrochemical impedance spectroscopy was presented. The gold surface was modified with linear linkers (various mercaptoalkanoic acids and aminoalkanethiols) and poly(amidoamine) dendrimers from the first- to fifth-generation. The best functionalization procedure was established by detailed SPR studies and transferred onto gold electrodes to electrochemically examine the model enzymatic reaction catalysed by glutamate oxidase. In the case of the chronoamperometric method, the determined sensitivity was 3.36 ± 0.08 μA∙mM^-1, and the low limit of detection (LOD) was 1.52 μM. Comparing the sensitivity and LOD obtained for CV measurements, the values of these parameters were 2.5 times higher and 4 times lower, respectively, for the fourth-generation dendrimer-based biosensor and the biosensor with a linear linker. The positive impact of the dendrimer interlayer on the long-term enzyme activity was also confirmed. The research results indicate the possibility of a significant increase in the sensor response using the dendrimer itself without enriching it with electrochemical components.

The Emerging Role of N-Methyl-D-Aspartate (NMDA) Receptors in the Cardiovascular System: Physiological Implications, Pathological Consequences, and Therapeutic Perspectives

N-methyl-D-aspartate receptors (NMDARs) are ligand-gated ion channels that are activated by the neurotransmitter glutamate, mediate the slow component of excitatory neurotransmission in the central nervous system (CNS), and induce long-term changes in synaptic plasticity. NMDARs are non-selective cation channels that allow the influx of extracellular Na⁺ and Ca²⁺ and control cellular activity via both membrane depolarization and an increase in intracellular Ca²⁺ concentration. The distribution, structure, and role of neuronal NMDARs have been extensively investigated and it is now known that they also regulate crucial functions in the non-neuronal cellular component of the CNS, i.e., astrocytes and cerebrovascular endothelial cells. In addition, NMDARs are expressed in multiple peripheral organs, including heart and systemic and pulmonary circulations. Herein, we survey the most recent information available regarding the distribution and function of NMDARs within the cardiovascular system. We describe the involvement of NMDARs in the modulation of heart rate and cardiac rhythm, in the regulation of arterial blood pressure, in the regulation of cerebral blood flow, and in the blood-brain barrier (BBB) permeability. In parallel, we describe how enhanced NMDAR activity could promote ventricular arrhythmias, heart failure, pulmonary artery hypertension (PAH), and BBB dysfunction. Targeting NMDARs could represent an unexpected pharmacological strategy to reduce the growing burden of several life-threatening cardiovascular disorders.

Nonenzymatic Electrochemical Glutamate Sensor Using Copper Oxide Nanomaterials and Multiwall Carbon Nanotubes

Glutamate is an important neurotransmitter due to its critical role in physiological and pathological processes. While enzymatic electrochemical sensors can selectively detect glutamate, enzymes cause instability of the sensors, thus necessitating the development of enzyme-free glutamate sensors. In this paper, we developed an ultrahigh sensitive nonenzymatic electrochemical glutamate sensor by synthesizing copper oxide (CuO) nanostructures and physically mixing them with multiwall carbon nanotubes (MWCNTs) onto a screen-printed carbon electrode. We comprehensively investigated the sensing mechanism of glutamate; the optimized sensor showed irreversible oxidation of glutamate involving one electron and one proton, and a linear response from 20 μM to 200 μM at pH 7. The limit of detection and sensitivity of the sensor were about 17.5 μM and 8500 μA·mM^-1·cm^-2, respectively. The enhanced sensing performance is attributed to the synergetic electrochemical activities of CuO nanostructures and MWCNTs. The sensor detected glutamate in whole blood and urine and had minimal interference with common interferents, suggesting its potential for healthcare applications.

Efforts toward the continuous monitoring of molecular markers of performance

OBJECTIVES

Technologies supporting the continuous, real-time measurement of blood oxygen saturation and plasma glucose levels have improved our ability to monitor performance status. Our ability to monitor other molecular markers of performance, however, including the hormones known to indicate overtraining and general health, has lagged. That is, although a number of other molecular markers of performance status have been identified, we have struggled to develop viable technologies supporting their real-time monitoring in the body. Here we review biosensor approaches that may support such measurements, as well as the molecules potentially of greatest interest to monitor.

DESIGN

Narrative literature review.

METHOD

Literature review.

RESULTS

Significant effort has been made to harness the specificity, affinity, and generalizability of biomolecular recognition in a platform technology supporting continuous in vivo molecular measurements. Most biosensor approaches, however, are either not generalizable to most targets, or fail when challenged in the complex environments found in vivo. Electrochemical aptamer-based sensors, in contrast, are the first technology to simultaneously achieve both of these critical attributes. In an effort to illustrate the potential of this platform technology, we both critically review the literature describing it and briefly survey some of the molecular performance markers we believe will prove advantageous to monitor using it.

CONCLUSIONS

Electrochemical aptamer-based sensors may be the first truly generalizable technology for monitoring specific molecules in situ in the body and how adaptation of the platform to subcutaneous microneedles will enable the real-time monitoring of performance markers via a wearable, minimally invasive device.

Topical review - salivary biomarkers in chronic muscle pain

BACKGROUND AND AIMS

Muscle related temporomandibular disorders (myogenous TMD), one of the most common orofacial pain conditions, is characterized by facial pain and often accompanied by jaw movement limitations. Although the underlying biological mechanisms are still unclear, a cluster of proteins and peptides is assumed to be involved in the pathophysiology. These proteins and peptides may be measured in a simple non-invasive saliva sample. This work investigated whether saliva can be used to sample algogenic substances that can serve as molecular biomarkers for TMD myalgia.

METHODS

Saliva and blood samples were collected from healthy individuals (n=69) and patients diagnosed with TMD myalgia (n=39) according to the Diagnostic Criteria for TMD. Unstimulated and stimulated whole, parotid, and sublingual saliva were analysed. The protein profiles were investigated using two-dimensional gel electrophoresis followed by identification with liquid chromatography tandem mass spectrometry. Levels of nerve growth factor (NGF), calcitonin gene-related peptide (CGRP), and brain derived neuro-tropic factor (BDNF) were determined using western blotting based technology and multiplex electro-chemiluminescence assay panel. Glutamate, serotonin, and substance p (SP) were determined using commercially available methods.

RESULTS

Different saliva collection approaches resulted in significant differences in the protein profile as well as in the expression of NGF, BDNF, CGRP, SP, and glutamate. Stimulated whole saliva showed least variability in protein concentration (35%) and was correlated to plasma levels of glutamate. Unlike SP and glutamate, NGF and BDNF expressed a rhythmic variation in salivary expression with higher levels in the morning (p<0.05). Patients with a diagnosis of TMD myalgia had significantly higher levels of salivary glutamate but lower salivary NGF and BDNF compared to controls; in addition, the lower NGF and BDNF levels correlated to psychological dysfunction. The quantitative proteomics data revealed 20 proteins that were significantly altered in patients compared to controls. The identified proteins are involved in metabolic processes, immune response, and stress response. Dissimilarities in protein profile and clinical variables were observed between TMD myalgia and myofascial pain.

CONCLUSIONS

The work highlights the importance of consistency in saliva collection approaches, including the timing of the collection. It displayed significant changes in pain specific mediators and protein profile in TMD myalgia and furthermore dissimilarities between subclasses indicating different pathophysiology. After extensive validation, potential salivary biomarkers can be combined with clinical features to better understand and diagnose TMD myalgia.

Overview of Engineering Carbon Nanomaterials Such As Carbon Nanotubes (CNTs), Carbon Nanofibers (CNFs), Graphene and Nanodiamonds and Other Carbon Allotropes inside Porous Anodic Alumina (PAA) Templates

The fabrication and design of carbon-based hierarchical structures with tailored nano-architectures have attracted the enormous attention of the materials science community due to their exceptional chemical and physical properties. The collective control of nano-objects, in terms of their dimensionality, orientation and size, is of paramount importance to expand the implementation of carbon nanomaterials across a large variety of applications. In this context, porous anodic alumina (PAA) has become an attractive template where the pore morphologies can be straightforwardly modulated. The synthesis of diverse carbon nanomaterials can be performed using PAA templates, such as carbon nanotubes (CNTs), carbon nanofibers (CNFs), and nanodiamonds, or can act as support for other carbon allotropes such as graphene and other carbon nanoforms. However, the successful growth of carbon nanomaterials within ordered PAA templates typically requires a series of stages involving the template fabrication, nanostructure growth and finally an etching or electrode metallization steps, which all encounter different challenges towards a nanodevice fabrication. The present review article describes the advantages and challenges associated with the fabrication of carbon materials in PAA based materials and aims to give a renewed momentum to this topic within the materials science community by providing an exhaustive overview of the current synthesis approaches and the most relevant applications based on PAA/Carbon nanostructures materials. Finally, the perspective and opportunities in the field are presented.

Consequence of COVID-19 occurrences in wastewater with promising recognition and healing technologies: A review

Presently, the coronavirus (COVID-19) epidemic presents a major threat to global communal fitness also socio-financial development. Ignoring worldwide isolation as well as shutdown attempts, the occurrence of COVID-19 infected patients continues to be extremely large. Nonetheless, COVID-19's final course, combined with the prevalence of emerging contaminants (antibiotics, pharmaceuticals, nanoplastics, pesticides, and so forth) in wastewater treatment plants (WWTPs), presents a major problem in wastewater situations. The research, therefore, intends near examine an interdisciplinary as well as technical greet to succor COVID-19 with subsequent COVID cycles of an epidemic as a framework for wastewater treatment settings. This research investigated the potential for wastewater-based epidemiology to detect SARS-CoV-2 also the enzymes happening in wastewater conditions. In addition, a chance for the incorporation into the WWTPs of emerging and robust technologies such as mesmeric nanobiotechnology, electrochemical oxidation, microscopy, and membrane processes to enhance the overall likelihood of environmental consequences of COVID-19 also strengthen such quality of water is resolved.

Porous Carbon Boosted Non-Enzymatic Glutamate Detection with Ultra-High Sensitivity in Broad Range Using Cu Ions

A non-enzymatic electrochemical sensor, based on the electrode of a chitosan-derived carbon foam, has been successfully developed for the detection of glutamate. Attributed to the chelation of Cu ions and glutamate molecules, the glutamate could be detected in an amperometric way by means of the redox reactions of chelation compounds, which outperform the traditional enzymatic sensors. Moreover, due to the large electroactive surface area and effective electron transportation of the porous carbon foam, a remarkable electrochemical sensitivity up to 1.9 × 10⁴ μA/mM∙cm² and a broad-spectrum detection range from nM to mM scale have been achieved, which is two-orders of magnitude higher and one magnitude broader than the best reported values thus far. Furthermore, our reported glutamate detection system also demonstrates a desirable anti-interference ability as well as a durable stability. The experimental revelations show that the Cu ions chelation-assisted electrochemical sensor with carbon foam electrode has significant potential for an easy fabricating, enzyme-free, broad-spectrum, sensitive, anti-interfering, and stable glutamate-sensing platform.

Biosensors Integration in Blood-Brain Barrier-on-a-Chip: Emerging Platform for Monitoring Neurodegenerative Diseases

Over the most recent decades, the development of new biological platforms to study disease progression and drug efficacy has been of great interest due to the high increase in the rate of neurodegenerative diseases (NDDs). Therefore, blood–brain barrier (BBB) as an organ-on-a-chip (OoC) platform to mimic brain-barrier performance could offer a deeper understanding of NDDs as well as a very valuable tool for drug permeability testing for new treatments. A very attractive improvement of BBB-oC technology is the integration of detection systems to provide continuous monitoring of biomarkers in real time and a fully automated analysis of drug permeably, rendering more efficient platforms for commercialization. In this Perspective, an overview of the main BBB-oC configurations is introduced and a critical vision of the BBB-oC platforms integrating electronic read out systems is detailed, indicating the strengths and weaknesses of current devices, proposing the great potential for biosensors integration in BBB-oC. In this direction, we name potential biomarkers to monitor the evolution of NDDs related to the BBB and/or drug cytotoxicity using biosensor technology in BBB-oC.

Fatty Acid-Binding Protein 7 (FABP-7), Glutamic Acid and Neurofilament Light Chain (NFL) as Potential Markers of Neurodegenerative Disorders in Psoriatic Patients-A Pilot Study

Psoriasis and neurodegenerative diseases (NDs) are important medical, social and economic issues. The possible relationship of psoriasis and NDs has not been established yet. This study involved 60 patients with plaque-type psoriasis. Serum concentrations of fatty acid-binding protein 7 (FABP-7), glutamic acid (GA) and neurofilament light chain (NFL), which have been hardly studied in psoriasis before, were measured by ELISA before and after 12 weeks of treatment with acitretin or methotrexate. The concentration of FABP-7 and NFL in patients before the treatment was significantly higher than in the controls (p < 0.01, p < 0.001, respectively). After the treatment their concentration decreased, although FABP-7 did so insignificantly. The concentration of GA did not differ significantly between patients and controls and before and after the treatment but we found its negative correlation with CRP (p < 0.05). The duration of psoriasis does not seem to directly affect the risk of neurodegeneration and the severity only in patients with worse skin condition. Elevated FABP-7 and NFL, which are present in the brain, may be considered as potential indicators of NDs development in psoriatics, although it surely requires further research. GA might correspond with neuroinflammation in psoriasis. Systemic antipsoriatic therapy could be studied in order to improve cognitive impairment through lowering NDs biomarkers in some cases.

Continuous Lactate Monitoring System Based on Percutaneous Microneedle Array

Lactate measurement is important in the fields of sports and medicine. Lactate accumulation can seriously affect an athlete’s performance. The most common problem caused by lactate accumulation in athletes is muscle soreness due to excessive exercise. Moreover, from a medical viewpoint, lactate is one of the main prognostic factors of sepsis. Currently, blood sampling is the most common approach to lactate measurement for lactate sensing, and continuous measurement is not available. In this study, a low-cost continuous lactate monitoring system (CLMS) is developed based on a percutaneous microneedle array that uses a three-electrode lactate sensor. The working electrode has an area of 10 mm × 6 mm, including a 3 × 3 array of stainless-steel microneedles. The length, width, and thickness of each needle are 1 mm, 0.44 mm, and 0.03 mm, respectively. The working electrode is then plated with gold, polyaniline, lactate enzyme, Nafion, and Poly(2-hydroxyethyl methacrylate) (poly HEMA). The reference electrode is a 2 × 1 array covered with AgCl, and the counter electrode is a 2 × 1 array plated with gold. The sensor is incorporated into the CLMS and connected to a smartphone application and the cloud. The CLMS was tested on 40 human subjects who rode indoor bicycles, starting at 100 W and increasing in steps of 25 W at intervals of 5 min until exhaustion. The data acquired from the app connected to the CLMS were analyzed to determine the subjects’ lactate response to exercise and the feasibility of assessing exercise performance and training exercise intensity by using the proposed system.

Redox Sensor Array with 23.5-μm Resolution for Real-Time Imaging of Hydrogen Peroxide and Glutamate Based on Charge-Transfer-Type Potentiometric Sensor

Towards clarifying the spatio-temporal neurotransmitter distribution, potentiometric redox sensor arrays with 23.5-µm resolution were fabricated. The sensor array based on a charge-transfer-type potentiometric sensor comprises 128×128 pixels with gold electrodes deposited on the surface of pixels. The sensor output corresponding to the interfacial potential of the electrode changed logarithmically with the mixture ratio of K3Fe(CN)6 and K4Fe(CN)6, where the redox sensitivity reached 49.9 mV/dec. By employing hydrogen peroxidase as an enzyme and ferrocene as an electron mediator, the sensing characteristics for hydrogen peroxide (H2O2) were investigated. The analyses of the sensing characteristics revealed that the sensitivity was about 44.7 mV/dec., comparable to the redox sensitivity, while the limit of detection (LOD) was achieved to be 1 µM. Furthermore, the oxidation state of the electron mediator can be the key to further lowering the LOD. Then, by immobilizing oxidizing enzyme for H2O2 and glutamate oxidase, glutamate (Glu) measurements were conducted. As a result, similar sensitivity and LOD to those of H2O2 were obtained. Finally, the real-time distribution of 1 µM Glu was visualized, demonstrating the feasibility of our device as a high-resolution bioimaging technique.

Development of sponge-like cellulose colorimetric swab immobilized with anthocyanin from red-cabbage for sweat monitoring

Novel sponge-like biochromic swab was developed via immobilization of natural anthocyanin (Cy) biomolecular probe into microporous cellulose aerogel. The current biosensor is characterized with simple preparation, environmentally-friendly, biocompatibility, biodegradability, flexibility, portability and reversibility. This biochromic sponge-like aerogel detector displayed a color change from pink to green-yellow in response to the biochemical changes occurs to sweat. This could be ascribed to intramolecular charge transfer occurs to the molecular system of Cy. Thus, the anthocyanin probe displayed colorimetric variations in UV-Vis absorption spectra via a blue shifting from 620 to 529 nm when raising the pH value of the prepared mimic sweat solution. Natural pH sensitive anthocyanin spectroscopic probe was extracted from red-cabbage plant, characterized by HPLC, and encapsulated into microporous cellulose. The microporous sponge-like cellulose swab was prepared by activating wood pulp utilizing phosphoric acid, and then subjected to freeze-drying. This anthocyanin probe is highly soluble in water. Thus, it was encapsulated as a direct dye into cellulose substrate during the freeze-drying process. To allow a better fixation of this water-soluble anthocyanin probe to the cellulose substrate, potash alum was added to the freeze-dried mixture to act as a fixing agent or mordant (M) generating Cy/M coordination complex. The produced Cy/M nanoparticles (NPs) were explored by transmission electron microscopy (TEM). The morphological features of the generated aerogels were investigated by scan electron microscope (SEM), energy-dispersive X-ray (EDX) spectra, and Fourier-transform infrared spectra (FT-IR). The cytotoxicity of the prepared aerogel-based biosensor was also evaluated. The naked-eye colorimetric changes were studied by exploring color strength, UV-Vis spectra and CIE Lab colorimetric coordinates.

Cultivating Multidisciplinarity: Manufacturing and Sensing Challenges in Cultured Meat Production

Meat cultivation via cellular agriculture holds great promise as a method for future food production. In theory, it is an ideal way of meat production, humane to the animals and sustainable for the environment, while keeping the same taste and nutritional values as traditional meat and having additional benefits such as controlled fat content and absence of antibiotics and hormones used in the traditional meat industry. However, in practice, there is still a number of challenges, such as those associated with the upscale of cultured meat (CM). CM food safety monitoring is a necessary factor when envisioning both the regulatory compliance and consumer acceptance. To achieve this, a multidisciplinary approach is necessary. This includes extensive development of the sensitive and specific analytical devices i.e., sensors to enable reliable food safety monitoring throughout the whole future food supply chain. In addition, advanced monitoring options can help in the further optimization of the meat cultivation which may reduce the currently still high costs of production. This review presents an overview of the sensor monitoring options for the most relevant parameters of importance for meat cultivation. Examples of the various types of sensors that can potentially be used in CM production are provided and the options for their integration into bioreactors, as well as suggestions on further improvements and more advanced integration approaches. In favor of the multidisciplinary approach, we also include an overview of the bioreactor types, scaffolding options as well as imaging techniques relevant for CM research. Furthermore, we briefly present the current status of the CM research and related regulation, societal aspects and challenges to its upscaling and commercialization.

Electrochemical sensing: A prognostic tool in the fight against COVID-19

The COVID-19 pandemic has devastated the world, despite all efforts in infection control and treatment/vaccine development. Hospitals are currently overcrowded, with health statuses of patients often being hard to gauge. Therefore, methods for determining infection severity need to be developed so that high-risk patients can be prioritized, resources can be efficiently distributed, and fatalities can be prevented. Electrochemical prognostic biosensing of various biomarkers may hold promise in solving these problems as they are low-cost and provide timely results. Therefore, we have reviewed the literature and extracted the most promising biomarkers along with their most favourable electrochemical sensors. The biomarkers discussed in this paper are C-reactive protein (CRP), interleukins (ILs), tumour necrosis factor alpha (TNFα), interferons (IFNs), glutamate, breath pH, lymphocytes, platelets, neutrophils and D-dimer. Metabolic syndrome is also discussed as comorbidity for COVID-19 patients, as it increases infection severity and raises chances of becoming infected. Cannabinoids, especially cannabidiol (CBD), are discussed as a potential adjunct therapy for COVID-19 as their medicinal properties may be desirable in minimizing the neurodegenerative or severe inflammatory damage caused by severe COVID-19 infection. Currently, hospitals are struggling to provide adequate care; thus, point-of-care electrochemical sensor development needs to be prioritized to provide an approximate prognosis for hospital patients. During and following the immediate aftermath of the pandemic, electrochemical sensors can also be integrated into wearable and portable devices to help patients monitor recovery while returning to their daily lives. Beyond the COVID-19 pandemic, these sensors will also prove useful for monitoring inflammation-based diseases such as cancer and cardiovascular disease.

Cerebrospinal fluid glutamate changes in functional movement disorders

The aim of this study was to assess cerebrospinal fluid (CSF) concentrations of specific amino acids using a high-performance liquid chromatography system in a sample of patients with functional movement disorders (FMDs) and in a sample of controls. CSF levels of glutamate were significantly lower in patients with FMD than in controls. This finding argues in favor of glutamatergic dysfunction in the pathophysiology of FMD.

Metal Nanocomposites Based Electrochemical Sensor Platform for few Emerging Biomarkers

:

Design of high-performance electrochemical sensor and biosensor platforms has attracted much devotion for the sensitive and selective detection of emergent biomarkers. Electrochemical sensor offers numerous advantageous features include cost-effective and ease of miniaturization, rapid and online monitoring, simultaneous detection ability, etc., which have captivated the potential interdisciplinary research. In this review, the advances and challenges towards the electrochemical detection of emergent biomarkers such as hydrogen peroxide, nitric oxide, β-nicotinamide adenine acetaminophen, dinucleotide (NADH) in biofluids are highlighted based on the recent research outcomes. In fact, the effective utility and benefits of transition metal nanocomposites without the utilization of biological materials, including enzymes, antibodies, etc. as electrode materials towards the detection of selected biomarkers in practical biofluids, monitoring early-stage and diagnosis of disease related biomarkers, are also described. These promising metal nanomaterials based electrochemical sensor platforms concrete the tactic for a new generation of sensing devices.

Design of a mediator-free, non-enzymatic electrochemical biosensor for glutamate detection

A mediator-free, non-enzymatic electrochemical biosensor was constructed by covalent immobilization of a genetically engineered periplasmic glutamate binding protein onto gold nanoparticle-modified, screen-printed carbon electrodes (GluBP/AuNP/SPCE) for the purpose of direct measurement of glutamate levels. Glutamate serves as the predominant excitatory neurotransmitter in the central nervous system. As high levels of glutamate are an indicator of many neurologic disorders, there is a need for advancements in glutamate detection technologies. The biosensor was evaluated for glutamate detection by cyclic voltammetry. Binding of glutamate to the immobilized glutamate binding protein results in a conformational change of the latter that alters the microenvironment on the surface of the sensor, which is manifested as a change in signal. Dose-response plots correlating the electrochemical signal to glutamate concentration revealed a detection limit of 0.15 μM with a linear range of 0.1-0.8 μM. Selectivity studies confirmed a strong preferential response of the biosensor for glutamate against common interfering compounds.

Fate of COVID-19 Occurrences in Wastewater Systems: Emerging Detection and Treatment Technologies—A Review

The coronavirus (COVID-19) pandemic is currently posing a significant threat to the world’s public health and social-economic growth. Despite the rigorous international lockdown and quarantine efforts, the rate of COVID-19 infectious cases remains exceptionally high. Notwithstanding, the end route of COVID-19, together with emerging contaminants’ (antibiotics, pharmaceuticals, nanoplastics, pesticide, etc.) occurrence in wastewater treatment plants (WWTPs), poses a great challenge in wastewater settings. Therefore, this paper seeks to review an inter-disciplinary and technological approach as a roadmap for the water and wastewater settings to help fight COVID-19 and future waves of pandemics. This study explored wastewater–based epidemiology (WBE) potential for detecting SARS-CoV-2 and its metabolites in wastewater settings. Furthermore, the prospects of integrating innovative and robust technologies such as magnetic nanotechnology, advanced oxidation process, biosensors, and membrane bioreactors into the WWTPs to augment the risk of COVID-19’s environmental impacts and improve water quality are discussed. In terms of the diagnostics of COVID-19, potential biosensors such as sample–answer chip-, paper- and nanomaterials-based biosensors are highlighted. In conclusion, sewage treatment systems, together with magnetic biosensor diagnostics and WBE, could be a possible way to keep a surveillance on the outbreak of COVID-19 in communities around the globe, thereby identifying hotspots and curbing the diagnostic costs of testing. Photocatalysis prospects are high to inactivate coronavirus, and therefore a focus on safe nanotechnology and bioengineering should be encouraged.

Salivary Alpha-Amylase in Experimentally-Induced Muscle Pain

Salivary alpha-amylase (sAA) is a marker of psychological stress and might also be a potential marker for pain-associated stress due its non-invasive, cost-effective, and stress-free collection. The current study aimed to investigate whether the levels of sAA are influenced by experimentally induced muscle pain. In this study, 26 healthy, pain-free and age-matched participants (23.8 ± 2.6 years) were included, 13 women and 13 men. Prior to the experiment, questionnaires assessing health and anxiety were completed. Muscle pain was then induced through intramuscular injection of 0.4 mL hypertonic saline (56.5 mg/mL) into the masseter muscle and unstimulated whole saliva samples were collected at baseline before injection, 2 min, and 15 min after injection. A commercially available colorimetric assay was used to analyze the sAA. Perceived pain and stress were assessed using a 0–100 Numeric Rating Scale for each sample. There were no significant differences in sAA levels prior and after injection of hypertonic saline (p > 0.05) although sAA levels showed a slight decrease during experimentally-induced muscle pain. However, a strong correlation was observed between self-reported pain and perceived level of stress during experimentally-induced muscle pain (r₂ = 0.744; p < 0.0001). Furthermore, there was a moderate correlation between the levels of sAA at baseline and during experimental pain (r₂ = 0.687; p < 0.0001). In conclusion, this study could not show any association between the levels of sAA and perceived pain and or/stress. However, since a significant strong correlation could be observed between perceived stress and pain intensity, this study indicates that experimentally-induced muscle pain could be used as a stress model.

In Vivo Glutamate Sensing inside the Mouse Brain with Perovskite Nickelate-Nafion Heterostructures

Glutamate, one of the main neurotransmitters in the brain, plays a critical role in communication between neurons, neuronal development, and various neurological disorders. Extracellular measurement of neurotransmitters such as glutamate in the brain is important for understanding these processes and developing a new generation of brain-machine interfaces. Here, we demonstrate the use of a perovskite nickelate-Nafion heterostructure as a promising glutamate sensor with a low detection limit of 16 nM and a response time of 1.2 s via amperometric sensing. We have designed and successfully tested novel perovskite nickelate-Nafion electrodes for recording of glutamate release ex vivo in electrically stimulated brain slices and in vivo from the primary visual cortex (V1) of awake mice exposed to visual stimuli. These results demonstrate the potential of perovskite nickelates as sensing media for brain-machine interfaces.

Anhedonia to Gentle Touch in Fibromyalgia: Normal Sensory Processing but Abnormal Evaluation

Social touch is important for interpersonal interaction. Gentle touch and slow brushing are typically perceived as pleasant, the degree of pleasantness is linked to the activity of the C-tactile (CT) fibers, a class of unmyelinated nerves in the skin. The inability to experience pleasure in general is called anhedonia, a common phenomenon in the chronic pain condition fibromyalgia. Here, we studied the perception and cortical processing of gentle touch in a well-characterized cohort of fibromyalgia. Patients and controls participated in functional brain imaging while receiving tactile stimuli (brushing) on the forearm. They were asked to provide ratings of pleasantness of the tactile stimulus and ongoing pain. We found high distress, pain catastrophizing, and insomnia, and a low perceived state of health in fibromyalgia. Further, patients rated both slow (CT-optimal) and fast (CT-suboptimal) brushing as less pleasant than healthy participants. While there was no difference in brain activity during touch, patients showed deactivation in the right posterior insula (contralateral to the stimulated arm) during pleasantness rating and activation during pain rating. The opposite pattern was observed in healthy participants. Voxel-based morphometry analysis revealed reduced grey matter density in patients, in the bilateral hippocampus and anterior insula. Our results suggest anhedonia to gentle touch in fibromyalgia with intact early-stage sensory processing but dysfunctional evaluative processing. These findings contribute to our understanding of the mechanisms underlying anhedonia in fibromyalgia.

Advances in Translational Nanotechnology: Challenges and Opportunities

The burgeoning field of nanotechnology aims to create and deploy nanoscale structures, devices, and systems with novel, size-dependent properties and functions. The nanotechnology revolution has sparked radically new technologies and strategies across all scientific disciplines, with nanotechnology now applied to virtually every area of research and development in the US and globally. NanoFlorida was founded to create a forum for scientific exchange, promote networking among nanoscientists, encourage collaborative research efforts across institutions, forge strong industry-academia partnerships in nanoscience, and showcase the contributions of students and trainees in nanotechnology fields. The 2019 NanoFlorida International Conference expanded this vision to emphasize national and international participation, with a focus on advances made in translating nanotechnology. This review highlights notable research in the areas of engineering especially in optics, photonics and plasmonics and electronics; biomedical devices, nano-biotechnology, nanotherapeutics including both experimental nanotherapies and nanovaccines; nano-diagnostics and -theranostics; nano-enabled drug discovery platforms; tissue engineering, bioprinting, and environmental nanotechnology, as well as challenges and directions for future research.