Miniaturized electrochemical (MEC) sensors have been broadly applied to point-of-care testing (POCT) in various fields, including health care, food safety, and environmental monitoring, due to their ...easy operation, portability, high sensitivity, as well as their short analysis time. This review summarizes the state-of-the-art advancements on various types of MEC sensors, applications in POCT, and the future perspectives, opportunities, and challenges in this field.
Display omitted
Most of the current analytical methods depend largely on laboratory-based analytical techniques that require expensive and bulky equipment, potentially incur costly testing, and involve lengthy detection processes. With increasing requirements for point-of-care testing (POCT), more attention has been paid to miniaturized analytical devices. Miniaturized electrochemical (MEC) sensors, including different material-based MEC sensors (such as DNA-, paper-, and screen electrode-based), have been in strong demand in analytical science due to their easy operation, portability, high sensitivity, as well as their short analysis time. They have been applied for the detection of trace amounts of target through measuring changes in electrochemical signal, such as current, voltage, potential, or impedance, due to the oxidation/reduction of chemical/biological molecules with the help of electrodes and electrochemical units. MEC sensors present great potential for the detection of targets including small organic molecules, metal ions, and biomolecules. In recent years, MEC sensors have been broadly applied to POCT in various fields, including health care, food safety, and environmental monitoring, owing to the excellent advantages of electrochemical (EC) technologies. This review summarized the state-of-the-art advancements on various types of MEC sensors and their applications in POCT. Furthermore, the future perspectives, opportunities, and challenges in this field are also discussed.
MXenes are two–dimensional layered materials of early transition metal carbides and/or nitrides applied in multiple scientific applications ranging from catalysis, energy storage, to sensors owing to ...their fascinating and technologically useful properties. This review presents an overview of the current state–of the–art progresses in the field of electrochemical (bio) sensors for the detection of biomarkers, pharmaceutical drugs, and environmental contaminants. Firstly, how synthetic strategies and surface functionalization affect various properties of MXenes, and consequently, the sensing performances are highlighted. Secondly, MXenes as an electrode modifier for the detection of pharmaceutical drugs, environmental contaminants, and important disease biomarkers such as cancer biomarkers, glucose, hydrogen peroxide, etc., are well discussed. Finally, challenges in this field with possible solutions and future opportunities are discussed.
•Synthesis of MXenes and their functionalization strategies are discussed.•Current state–of the–art progresses in the field of MXene–based electrochemical (bio) sensors are reviewed.•Detection of disease biomarkers, pharmaceuticals, and environmental contaminants are highlighted.•The analytical performances of these sensors are compared with literature, and their strength/weaknesses are discussed.•Present challenges with possible solutions and future research opportunities are discussed.
Conventional methods like chromatography and spectroscopic analysis have limitations in detecting luteolin. However, electrochemical detection shows promise for reliable analysis. In this study, we ...compared two different morphologies of SnO2 with the same crystal structure for luteolin detection and found that crystal morphology significantly impacts the catalytic reaction. Compared to SnO2 quantum dots (SnO2 QDs), mesoporous SnO2 (m-SnO2) exhibited a larger specific surface area, providing more active sites for oxidation and reduction reactions. Moreover, m-SnO2 had lower impedance, effectively accelerating charge transfer at the electrode surface. Based on these excellent characteristics, m-SnO2/GCE modified electrode demonstrated outstanding performance in detecting luteolin, achieving a sensitivity of 8.5 μA μM-1, a low limit of 0.19 nM and a wide linear range from 0.5 nM to 1,400 nM. Besides, the m-SnO2/GC electrode displayed excellent consistency, reproducibility, durability, repeatability and specificity. Even three-week exposure to atmospheric conditions, the DPV signal stood at 94.1 % of its original peak current. Those enables its excellent application in practical sample detection. This research enhances our understanding of the influence of material structure and interface on catalytic luteolin detection, providing a theoretical foundation for accurate detection in complex systems. These findings should contribute to the development of more efficient, sensitive, and reliable luteolin sensors.
Display omitted
•A m-SnO2 material with outstanding surface area was synthesized.•The m-SnO2 providing sufficient channels for the movement of luteolin molecules.•The m-SnO2 electrode showed an ultra-low LOD of 0.19 nM.•The m-SnO2 electrode achieved accurate detection in actual samples.
Display omitted
•Chitosan is one of the most available natural biopolymer that has been extensively studied for a wide range of applications in a green economy and sustainable frame.•A great ...development and integration of functional nanomaterials for the advancement of electrochemical (bio)sensors has been recorded in literature.•Chitosan functionalisation strategies and chitosan-functional nanomaterials improve the overall analytical performance of electrochemical (bio)sensors in many applications.•The modifications/functionalisation of (nano)chitosan to improve sensing capability and the technique of fabrication of chitosan-based (bio)sensors are discussed on the base of recent literature works.
Chitosan (Chit) is one of the most available natural biopolymer that have been extensively studied for wide range of applications such as biomedical, drug delivery, energy, environmental remediation and food industry. In this review, we have collected and discussed research literature of recent years dealing with modification/functionalization of Chit at the nanoscale and techniques of synthesis of Chit-based materials for application in electrochemical (bio)sensors. Chit-based nanomaterials functionalization strategies and the state-of-art of their incorporation to advance electrochemical (bio)sensors in various fields of applications have been thoroughly discussed together with the most effective methods of Chit deposition (molecular imprinting, layer-by-layer, and electrodeposition) and the role of Chit in biosensing promotion.
Enzymatic and microbial electrochemical biosensors integrate enzymes and microorganisms as biological recognition elements into the sensor design and functionality. Enzyme-based sensors offer high ...sensitivity and selectivity for target analyte detection. However, these have limited stability necessary for continuous analyte monitoring. Contrarily, microbe-based electrochemical sensors provide a means for continuous analyte sensing but are associated with challenges related to analyte selectivity in complex samples. To address these limitations, surface-display methods, which bind enzymes to microbial surfaces, enhance biosensor selectivity and sensitivity. This perspective outlines the application of surface-display techniques, offering a promising avenue for health monitoring.
This review summarizes the synthesis of gold (Au) and Au-based nanomaterials and their recent advances of application in electrochemical small-molecule sensors, DNA sensors and immunosensors. Au ...nanoparticles with various shape and size have been synthesized by using physical, chemical, biological, electrochemical and seeding growth methods. In order to broaden the applications and improve the functionality of Au nanoparticles, numerous Au-based nanocomposite materials have been developed, including bimetallic nanoparticles, metal oxide-gold, polymer-gold, carbon nanotube-gold and graphene/graphene oxide-gold nanocomposites. Finally, the application of Au nanoparticles and Au-based nanocomposite materials in electrochemical sensors and their analytical performance were discussed.
Electrochemical sensor applications of Au and Au-based nanomaterials. Display omitted
•The morphology- and composition-controlled synthesis of Au and Au-based nanomaterials were discussed.•The application of Au and Au-based nanomaterials in electrochemical small-molecule sensors, DNA sensors and immunosensors was summarized.•This review emphasized on the features of different Au and Au-based nanomaterials as electrode materials for electrochemical sensing various analytes.
•MOF composites have been developed with superior electrocatalytic properties.•MOF composites can be applied as electrocatalysts for electrochemical sensing.•They were employed for sensing ...environmental analytes like metals and organics.•Their use was extended further to detect various biological targets like glucose.
Metal–organic frameworks (MOFs) are porous coordination polymers linked by metal ions and ligands. With the progress of MOF research, many redox active MOFs have been synthesized by judicious selection of the electroactive metal ions and/or organic functional groups. Due to the unique properties (e.g., high surface areas, tailorable pore sizes, and exposed active sites), MOFs are found to have a wide range of redox activities to be applied in various fields (e.g., microporous conductors, electrocatalysts, energy storage devices, and electrochemical sensors). The potential of the MOFs composites has also been realized as ideal hosts for functional materials (like conducting nanoparticles). These composites are thus demonstrated to have superior electrocatalytic/electrochemical sensing properties than their pristine forms. Accordingly, various MOF composite-based platforms have been developed as efficient electrochemical sensors for environmental and biochemical targets. This review was organized to provide up-to-date information and insights into the fundamental aspects of MOF composites as electrocatalytic/electrochemical sensors.
Quercetin is one of the flavonoids with antioxidant activity and has attracted great interest. Accurately and rapidly detection of quercetin belongs is of great significance. Herein, an ...ultrasensitive electrochemical quercetin sensor based on reduced graphene oxide/β-cyclodextrin/graphene quantum dots/molybdenum trioxide (rGO-β-CD/GQDs/MoO3) was constructed. The rGO-β-CD/GQDs/MoO3 presented excellent electrochemical detection for quercetin benefit from the excellent conductivity and adsorption enrichment effect of rGO-β-CD, good dispersion and stability of GQDs and electrocatalytic activity of MoO3. Under optimal conditions for the detection of quercetin, the rGO-β-CD/GQDs/MoO3/GCE showed wider linear range (5–2600 nM) and lower detection limit (LOD, 1.5 nM, (S/N = 3)). Furthermore, the sensor we constructed shows good accuracy and stability for the detection of quercetin in actual sample detections.
Display omitted
•A novel nanocomposite of rGO-β-CD/GQDs/MoO3 was firstly prepared.•rGO-β-CD has been successfully prepared by a simple one pot method.•The rGO-β-CD/GQDs/MoO3/GCE sensor showed a low limit of detection (LOD) of 1.5 nM.•The sensor has been successfully employed to detect quercetin in the actual samples.
Metal-organic frameworks (MOFs) are a class of functional porous three-dimensional framework materials exhibiting unique chemical properties. Owing to the multifunctional nature of MOFs including ...their electroactive functionality and structural porosity, significant progress has been achieved in the advancement of MOF-based electrochemical sensors. This review focuses on innovations over the past decade in electrochemical sensor systems based on MOFs and their composites. The relationships between the electrode construction strategies and sensing performance are discussed, in addition to shortcomings and limitations in the applications of these sensors. On this basis, we discuss the future scope and propose further directions for MOF-based electrochemical sensors.
A PEDOT:PSS conductive hydrogel is incorporated with Prussian blue nanoparticles for the highly sensitive in vitro glucose detection and is applied as a skin patch on human subjects for the in vivo ...noninvasive monitoring of interstitial fluid (ISF) glucose via reverse iontophoresis technology. The biosensor achieves good correlation with the finger-stick blood glucose measurement.
Display omitted
•The PEDOT:PSS/DF/PB hydrogel possessed an excellent operating stability.•The hydrogel-based sensor showed a competitive sensitivity of 340.1 μA·mM−1·cm−2.•The wearable sensor noninvasively monitored the ISF glucose through RI-extraction.•The sensor showed good correlation with the results from commerical glucometer.
Currently, there is no commercially-available noninvasive method for glucose monitoring in the interstitial fluid (ISF) mainly due to the measurement accuracy, sensitivity and/or the weak blood correlation. Here, we present an electrochemical biosensor based on PEDOT:PSS conductive hydrogel incorporated with Prussian blue nanoparticles (PBNPs) for the noninvasive and continuous monitoring of glucose on body. The hydrogel was prepared with the addition of dimethyl sulfoxide (DMSO) and Zonyl FS-300, which helped to improve the expanding of the polymer chains for the formation of better conductive and nanoporous networks. The hydrogel-based biosensor showed a low detection limit of 0.85 μM for glucose detection and high sensitivity up to 340.1 μA·mM−1·cm−2, which was about 10-fold higher than the counterparts based on agarose and hydroxyethyl methacrylate (HEMA) hydrogels. Furthermore, it provided good accuracy with commercial glucometer for the glucose detection in serum. More importantly, incorporated with the reverse iontophoresis (RI), the hydrogel was applied as a skin patch on human subject for the in vivo noninvasive and continuous monitoring of ISF-borne glucose. The results showed good correlation with that measured by blood glucometer. We believe such glucose biosensor paves the way to clinically wearable noninvasive glucose monitoring in diabetics.
