Leveraging electrochemical sensors to improve efficiency of cancer detection

Electrochemical biosensors have emerged as a promising technology for cancer detection due to their high sensitivity,rapid response,low cost,and capability for non-invasive detection.Recent advances in nanomaterials like nanoparticles,graphene,and nanowires have enhanced sensor performance to allow for cancer biomarker detection,like circulating tumor cells,nucleic acids,proteins and metabolites,at ultra-low concentrations.However,several challenges need to be addressed before electrochemical biosensors can be clinically implemented.These include improving sensor selectivity in complex biological media,device miniaturization for implantable applications,integration with data analytics,handling biomarker variability,and navigating regulatory approval.This editorial critically examines the prospects of electrochemical biosensors for efficient,low-cost and minimally invasive cancer screening.We discuss recent developments in nanotechnology,microfabrication,electronics integration,multiplexing,and machine learning that can help realize the potential of these sensors.However,significant interdisciplinary efforts among researchers,clinicians,regulators and the healthcare industry are still needed to tackle limitations in selectivity,size constraints,data interpretation,biomarker validation,toxicity and commercial translation.With committed resources and pragmatic strategies,electrochemical biosensors could enable routine early cancer detection and dramatically reduce the global cancer burden.

Tumor cell membrane-coated continuous electrochemical sensor for GLUT1 inhibitor screening

Glucose transporter 1(GLUT1)overexpression in tumor cells is a potential target for drug therapy,but few studies have reported screening GLUT1 inhibitors from natural or synthetic compounds.With current analysis techniques,it is difficult to accurately monitor the GLUT1 inhibitory effect of drug molecules in real-time.We developed a cell membrane-based glucose sensor(CMGS)that integrated a hydrogel electrode with tumor cell membranes to monitor GLUT1 transmembrane transport and screen for GLUT1 inhibitors in traditional Chinese medicines(TCMs).CMGS is compatible with cell membranes of various origins,including different types of tumors and cell lines with GLUT1 expression knocked down by small interfering RNA or small molecules.Based on CMGS continuous monitoring technique,we investigated the glucose transport kinetics of cell membranes with varying levels of GLUT1 expression.We used CMGS to determine the GLUT1-inhibitory effects of drug monomers with similar structures from Scutellaria baicalensis and catechins families.Results were consistent with those of the cellular glucose uptake test and molecular-docking simulation.CMGS could accurately screen drug molecules in TCMs that inhibit GLUT1,providing a new strategy for studying transmembrane protein-receptor interactions.

Cu(OH)_(2)/CMC one-dimensional composite-nanofiber-based electrochemical sensor for aspirin detection

Copper-based nanomaterials have been widely used in catalysis,electrodes,and other applications due to their unique electron-transfer properties.In this work,an efficient electrochemical sensor based on an electrode modified with one-dimensional Cu(OH)_(2)/carboxymethyl cellulose(CMC)composite nanofibers was fabricated and investigated for the detection of aspirin.Scanning electron microscopy was employed to examine the morphological characteristics of these composite nanofibers.Cyclic voltammetry and electrochemical impedance spectroscopy were used to assess the electrochemical performance of a Cu(OH)_(2)/CMC composite nanofiber-modified electrode.The findings indicate that the modified electrode has a very high sensitivity to aspirin.The observed enhanced performance could be a result of the high surface-to-volume ratio of the composite nanofibers and their superior electron-transport characteristics,which may hasten electron transfer between aspirin and the surfaces of the modified electrode.This detection technique also demonstrated strong selectivity for aspirin.These findings imply that the technique can be applied as a highly effective and selective approach to aspirin measurement in biological science.

Recent advances in two-dimensional nanomaterials-based electrochemical sensors for environmental analysis

With the rapidly increased concerns in environmental pollution, there have been urgent needs to develop fast, sensitive, low-cost and multiplexed sensing devices for the detection of environmental pollutants. Two-dimensional(2D) nanomaterials hold great promise due to their unique chemical and physical properties, which have been extensively employed to monitor the environmental pollutants combined with different detection techniques. In this review, we summarize recent advances in 2D nanomaterials-based electrochemical sensors for detecting heavy metal ions, organic compounds, pesticides, antibiotics and bacteria. We also discuss perspectives and challenges of 2D nanomaterials in environmental monitoring.

Nitrogen-doped carbon@TiO_(2) double-shelled hollow spheres as an electrochemical sensor for simultaneous determination of dopamine and paracetamol in human serum and saliva

As the most commonly used antipyretic and analgesic drug,paracetamol(PA)coexists with neurotransmitter dopamine(DA)in real biological samples.Their simultaneous determination is extremely important for human health,but they also interfere with each other.In order to improve the conductivity,adsorption affinity,sensitivity,and selectivity of TiO_(2)-based electrochemical sensor,N-doped carbon@-TiO_(2) double-shelled hollow sphere(HeC/N@TiO_(2))is designed and synthesized by simple alcoholic and hydrothermal method,using polystyrene sphere(PS)as a template.Meanwhile,TiO_(2) hollow spheres(H eTiO_(2))or N-doped carbon hollow spheres(HeC/N)are also prepared by the same method.HeC/N@TiO_(2) has good conductivity,charge separation,and the highly enhanced and stable current responses for the detection of PA and DA.The detection limit and linear range are 50.0 nmol/L and 0.3-50 mmol/L for PA,40.0 nmol/L and 0.3e50 mmol/L for DA,respectively,which are better than those of carbon-based sensors.Moreover,this electrochemical sensor,with high selectivity,strong anti-interference,high reliability,and long time durability,can be used for the simultaneous detection of PA and DA in human blood serum and saliva.The high electrochemical performance of HeC/N@TiO_(2) is attributed to the multifunctional combination of different layers,because of good conductivity,absorption and electrons transfer ability from in-situ N-doped carbon and electrocatalytic activity from TiO_(2).

Titanium dioxide-graphene composite electrochemical sensor for detection of hexavalent chromium

Hexavalent chromium(Cr(VI))compound is useful to various industries but is toxic and carcinogenic.In this research work,we fab-ricate an amperometric sensor for the determination of Cr(VI),using a titanium dioxide(TiO2)-reduced graphene oxide(rGO)composite as the sensing element.The composite was synthesized following sol−gel chemistry,yielding TiO2 nanoparticles of~50 nm in size,immobilized on chemically exfoliated rGO sheets.The composite was employed in a 3-electrode electrochemical cell and operated in an amperometric mode,exhibiting good responses to the 50 to 500 ppb Cr(VI).Our best result from pH 3 Mcilvane’s buffer medium reveals the sensitivity of 9.12×10−4 ppb−1 and a detection limit of 6 ppb with no signal interference from 200 ppm Ca(II),150 ppm Mg(II),and 50 ppb Pb(II).The excellent results of the TiO2-rGO sensor can be attributed to synergic effects between TiO2 and rGO,resulting from the presence of n-p heterojunctions and the formation of the TiO2 nanoparticles on rGO.

Progress of Solid Electrolytes and the Electrochemical Sensors

Four types of solid state electrochemical sensors and their general principles are introduced in the paper. The novel type-IV sensors developed in the last few years are emphasized to study hereafter. The ways to design new electrochemical sensors and the directions to develop new solid electrolytes for new electrochemical sensors are also discussed.

Research Surveys of Electrochemical Sensors for in-situ Determining Hydrogen in Steels

The principle, construction and application of two types of electrochemical sensors-amperometric and potentiometric are surveyed. Both types of sensors are very sensitive to changes in tempera- ture. The accuracy of hydrogen measurement depends on both the precision of sensors developed and the reliable technique of installation and security of sensors. The two types of sensors have been used for in-situ determining hydrogen permeated in steels owing to a corrosive reaction, a hydrogen gas circumstance at elevated temperatures and high pressure or also a pretreatment process such as pickling and plating process, etc.

A nonenzymatic electrochemical sensor for the detection of hydrogen peroxide in vitro and in vivo fibrosis models

Fibrosis occurs due to the excessive deposition of extracellular matrix caused by cell injury.After various types of tissue injury,the dysregulation of the internal response can eventually lead to the destruction of organ structure and dysfunction.There is increasing evidence that oxidative stress,which is characterized by excessive production of hydrogen peroxide(H_(2)O_(2)),is an important cause of fibrosis.Therefore,we synthesized a biosensitive and efficient electrochemical H_(2)O_(2)sensor based on PtNi nanoparticle-doped N-reduced graphene oxide(PtNi-N-rGO)to detect H_(2)O_(2)released from transforming growth factorβ1(TGFβ1)-induced myofibroblast.In addition,the sensor could easily detect changes in H_(2)O_(2)in the lung and bronchoalveolar lavage fluid(BALF)of mice with pulmonary fibrosis.Furthermore,the sensor could also detect H_(2)O_(2)in activated hepatic stellate cells and the liver of carbon tetrachloride(CCl_(4))-induced liver fibrosis.Moreover,the alterations in H_(2)O_(2)detected by the sensor were consistent with nicotinamide adenine dinucleotide phosphate oxidase 4(NOX4)protein expression and the staining results of pathological sections.Taken together,these results highlight the use of H_(2)O_(2)sensors for the rapid detection of fibrosis and facilitate the rapid evaluation of antifibrotic drug candidates.

Study of ZnO nanoparticle-supported clay minerals for electrochemical sensors,photocatalysis,and antioxidant applications

In view of the current study’s demonstration of the synthesis of clay-doped ZnO composites,we present a low-cost method for producing clay-metal oxide(clay/ZnO).Utilizing the solution combustion technique,a composite of clay/ZnO was produced utilizing citric acid as both a fuel and a complexing agent.The hexagonal unit cell structure of the created clay/ZnO may be seen using XRD patterns.The ZnO-infused clay was visible in FE-SEM micrographs as homogenous,sphere-shaped ZnO.The possible involvement of clay/ZnO photocatalytic activity in the UV-induced photodegradation of malachite green dye was investigated.The 90%degradation rate shows the composite’s outstanding photocatalytic degradation capacity.The resulting substance was electrochemically analyzed using a constructed electrode in 0.1 M KOH electrolyte.It increased its sensor capabilities,which now include chemical and biomolecule sensors,and it excelled in cyclic voltammetry-based redox potential studies.To efficiently evaluate chemically synthesized NPs for electrochemical,sensing,and photocatalytic applications,this study intends to create a solution combustion procedure for the synthesis of clay/ZnO nanocomposite using urea as fuel.

Rapid CO_(2)-laser scribing fabrication of an electrochemical sensor for the direct detection of Pb^(2+) and Cd^(2+)

Laser-induced graphene(LIG)is a highly promising preparation material for electrochemical sensors;however,its preparation speed and nanomaterial modification steps significantly limit its mass production.Herein,this study proposed a new laser printing strategy that considerably improved the preparation speed of LIG with excellent electrochemical performance.Using the optimal parameters(laser power of 1%,scribing spacing of 0.12 mm,scribing speed of 100 mm·s^(−1)),it took only 14.2 s to complete the preparation of the detection electrode.Thus,we successfully detected Cd^(2+)and Pb^(2+)without any toxic reagents or electrode modification steps.The limits of detection of the sensor were 0.914 and 0.916μg·L^(−1)for Cd^(2+)and Pb^(2+),respectively,which are significantly lower than the required values for drinking-water quality,according to the World Health Organization guidelines.This study provides a novel approach for the rapid detection of heavy-metal ions.

MXene-based electrochemical (bio) sensors for sustainable applications: Roadmap for future advanced materials

MXenes are emerging transition metal carbides and nitrides-based 2D conductive materials.They have found wide applications in sensors due to their excellent valuable properties.This paper reviews the recent research status of MXene-based electrochemical(bio)sensors for detecting biomarkers,pesticides,and other aspects.The first part of this paper introduced the synthesis strategy and the effect of surface modification on various prop-erties of MXenes.The second part of this paper discussed the application of MXenes as electrode modifiers for detecting pesticides,environmental pollutants,and biomarkers such as glucose,hydrogen peroxide,etc.Hope this review will inspire more efforts toward research on MXene-based sensors to meet the growing requirements.

Conductive MOFs for electrocatalysis and electrochemical sensor

Two-dimensional conductive metal–organic frameworks(2D-cMOFs)are a class of 2D layered MOFs with excellent electrical conductivity and other electronic properties.In recent years,their porous structure and dense active sites have been widely used in electrocatalysis and electrochemical sensing.The large electron delocalization domains generated by an extendedπ-conjugated framework through the covalent bonding between metal and organic ligand endow them with unique high conductivity.Yet despite a few promising applications,current research rarely addresses their“structure–property relationship.”This review discusses the rational design of 2DcMOFs with extraordinary electrochemical performance.We introduce several representative 2D-cMOFs and describe their applications,focusing on electrochemical catalysis and small molecule detection.By correlating the performance of the current materials in these applications and the corresponding mechanisms,we aim to uncover the key structural features that lead to their engineered properties and functions.

Sensitive and selective molecularly imprinted electrochemical sensor based on multi-walled carbon nanotubes for doxycycline hyclate determination

An electrochemical sensor for doxycycline hyclate(DC)detection with high sensitivity and good selectivity is reported.The sensor was fabricated by electro-polymerization of molecularly imprinted polymers(MIPs)in the presence of DC onto multi-walled carbon nanotubes modified glassy carbon electrode(MWCNTs/GCE).The MWCNTs can significantly increase the current response of the sensor,leading to enhanced sensitivity.The MIPs provide selective recognition sites for DC detection.The experimental parameters,such as the polymer monomer concentration,supporting electrolyte pH,the time for electro-polymerization and the incubation time of the sensor with DC were optimized.Under optimized experimental conditions,the sensor displayed a linear range of 0.05μmol/L-0.5μmol/L towards DC detection,with the detection limit of 1.3×10^-2μmol/L.The sensor was successfully applied for recovery test of DC in human serum samples.

Recent advances in electrochemical sensors for antibiotics and their applications

The abuse of antibiotics will cause an increase of drug-resistant strains and environmental pollution,which in turn will affect human health.Therefore,it is important to develop effective detection techniques to determine the level of antibiotics contamination in various fields.Compared with traditional detection methods,electrochemical sensors have received extensive attention due to their advantages such as high sensitivity,low detection limit,and good selectivity.In this mini review,we summarized the latest developments and new trends in electrochemical sensors for antibiotics.Here,modification methods and materials of electrode are discussed.We also pay more attention to the practical applications of antibiotics electrochemical sensors in different fields.In addition,the existing problems and the future challenges ahead have been proposed.We hope that this review can provide new ideas for the development of electrochemical sensors for antibiotics in the future.

Electrochemical Sensors Applied for In vitro Diagnosis

Electrochemical sensing technology has received extensive attention from researchers for its unique detection and analysis methods as well as the promising applications in clinical diagnosis.Compared with other detection methods,such as capillary electrophoresis,high‐performance liquid chromatography and liquid chromatography-tandem mass spectrometry,the electrochemical sensor overcomes the disadvantages of expensive cost and complicated operation,as an ideal device for in vitro detection.In this article,we mainly introduce some methods for the detection of biologically important compounds and cancer biomarkers,and briefly summarize the characteristics of these methods at first.And then,we also focus on the latest research progress in the application of electrochemical sensing technology to biologically important compounds’and cancer biomarkers’detection.Finally,the development trend and challenges of electrochemical sensing technology for in vitro diagnosis are also prospected.

Development of Non-enzymatic Cholesterol Electrochemical Sensor Based on Polyindole/Tungsten Carbide Nanocomposite

Non-enzymatic electrochemical sensor was developed for estimation of low-level cholesterol.Polyindole/tungsten carbide(PIN/WC)nanocomposite was synthesized and used as an electroactive material to develop low-cost modified stainless steel plate electrode(SSPE).Surface morphology of developed electrode was characterized by scanning electron microscopy.Electrochemical behavior of cholesterol was investigated through electron impedance spectroscopy,potentiodynamic polarization and cyclic voltammetry in 1-M KOH electrolytic solution.The quantification of cholesterol was studied by square wave voltammetry and differential pulse voltammetry.The calibration plots between the cholesterol concentration and peak current were in linear relation with limit of detection of 1.23×10^(−6) mol L^(−1).The overall result reveals that developed PIN/WC/SSPE electrode has excellent performance for trace-level cholesterol estimation and can be further employed for cholesterol monitoring in blood serum samples.

2D-titanium carbide(MXene)based selective electrochemical sensor for simultaneous detection of ascorbic acid,dopamine and uric acid

Two-dimensional(2 D)titanium carbide(MXene)nanosheets exhibited excellent conductivity,flexibility,high volumetric capacity,hydrophilic surface,thermal stability,etc.So,it has been exploited in various applications.Herein,we report synthesis of mixed phase 2 D MXene as a catalytic material for simultaneous detection of important biomolecules such as ascorbic acid(AA),dopamine(DA)and uric acid(UA).Crystalline structure,surface morphology and elemental composition of mixed phase titanium carbide(Ti-C-T_(x))MXene(T_(x)=-F,-OH,or-O)nanosheets were confirmed by X-ray diffraction(XRD),Raman spectroscopy,high-resolution transmission electron microscopy(HR-TEM),high-re solution scanning electron microscopy(HR-SEM)and Energy-dispersive X-ray spectroscopy(EDS)mapping analysis.Furthermore,Ti-C-T_(x) modified glassy carbon electrode(GCE)was prepared and its electrochemical properties are studied by cyclic voltammetry(CV)and diffe rential pulse voltammetry(DPV).It was found that Ti-C-T_(x) modified GCE(Ti-C-T_(x)/GCE)showed excellent electrocatalytic activity and separated oxidation peaks of important biomolecules such as AA(at 0.01 V),DA(at 0.21 V)and UA(at 0.33 V).Also,Ti-C-T_(x)/GCE sensor is enabled their simultaneous detection in physiological pH from 100 to 1000μM for AA,0.5-50μM for DA and 0.5-4μM&100-1500μM for UA.The limit of detection’s(LOD)was estimated as 4.6μM,0.06μM and 0.075μM for AA,DA and UA,respectively.Moreover,real sample analysis indicated that spiked AA,DA and UA can be determined accurately by Ti-C-T_(x)/GCE with the recovery ratio in the range between 100.5%-103%in human urine samples.The proposed Ti-C-T_(x) modified electrode exhibited good stability,selectivity and reproducibility as an electrochemical sensor for the detection of AA,DA and UA molecules.

A polyoxometalate based electrochemical sensor for efficient detection of L-cysteine

L-cysteine(L-cys),as an important sulfur-containing amino acid,plays an indispensable role in biological systems.Too low and excessively high ratio of L-cys will cause harm to the function of human organs.Therefore,it is very necessary to develop efficient methods to detect it in multifarious samples.This paper has built an electrochemical sensor by combining Keggin-type polyoxometalate(PMo9V3)and cobalt tetrasulfonate(Ⅱ)phthalocyanine(CoTsPc)on indium tin oxide electrodes using the layer-level self-assembly technology for efficiently detection of L-cys.The assembly process and surface morphology of the modified electrode was characterized by ultraviolet–visible spectroscopy,X-ray photoelectron spectroscopy,scanning electron microscope,and atomic force microscopy.The conditions of electro-catalysed oxidation of L-cys were optimized by cyclic voltammetry,and the kinetic electrochemical parameters were also evaluated by electrochemical impedance spectra.Furthermore,the sensing performance of the modified electrode was explored using amperometry.The proposed electrochemical L-cys sensor was found to have superior sensing performance with a range of linear response of 2.5×10^(−7) to 1.7×10^(−4) mol·L^(−1) and 1.7×10^(−4) to 39.5×10^(−4) mol·L^(−1),the detection limit of 1.0×10^(−7) mol·L^(−1)(signal/noise=3),and satisfactory anti-interference ability.Consequently,the fabricated sensor has the potential to be applied in laboratory practices for L-cys deterimination in commercial drinks.

A review on recent advances in hydrogen peroxide electrochemical sensors for applications in cell detection

Hydrogen peroxide(H_(2)O_(2))is a very simple bioactive small molecule.In living organisms,H_(2)O_(2)plays an important role in intracellular signaling.It is involved in many physiological processes including cellular physiology,intracellular signaling,oxidative damage and disease progression.The tumor microenvironment enriched with H_(2)O_(2).Several electrochemical sensors have been developed and some have been put on the market.Such electrochemical sensors provide efficient,cost-effective,rapid and highly selective method of H_(2)O_(2)detection.So far,much progress has been made in the designing of materials and construction of H_(2)O_(2)sensors.This review describes the advances in the application of H_(2)O_(2)electrochemical sensors in cell detection.Enzyme-based sensors have been applied in diverse applications.In addition,recent advancements in nanotechnology have improved the development of nanozymes-based sensors.The application of noble metals,metal oxides,polymers,carbon materials and other two-dimensional materials in the design of H_(2)O_(2)sensors are discussed in detail.Moreover,the bio-stimulant types of H_(2)O_(2)sensor are summarized.Finally,the challenges and future perspectives in the application of H_(2)O_(2)electrochemical sensors in biological detection are discussed.