Electro-chemiluminescent biosensing

Rapid and sensitive electrochemiluminescence detection using easily fabricated sensor with an integrated two-electrode system

The electrochemiluminescence (ECL) behavior of a tri(2,2'-bipyridyl)ruthenium(ii) (Ru(bpy)32+)/tripropylamine (TPrA) system was investigated in sensor chips with two kinds of integrated two-electrode systems, which included screen-printed electrodes (SPE) and physical vapor deposition (PVD) electrodes. Firstly, under excitation with an optimal transient potential (TP) within 100 ms, the ECL assay could be carried out on the microchips using an Au & Au electrode system, emitting strong and stable light signal. Secondly, on the PVD chip, the ECL intensity initiated by optimal TP was eight times stronger than the peak light signal emitted by the linear sweep voltammetry model. Finally, the logarithmic ECL intensities exhibited a linear increase with the logarithmic concentrations of Ru(bpy)32+ in both the SPE and PVD chips without any reference electrode (RE). Typically, the integration of an interdigital two-electrode system in the microchip significantly enhanced the ECL sensitivity of Ru(bpy)32+ because the large relative area between the working electrode (WE) and counter electrode (CE) achieved a highly efficient mass transfer. This improvement enabled the establishment of a reliable linear relationship across a wide concentration range, spanning from 1 pM to 1 μM (R2 = 0.998). Therefore, the exceptional ECL response of the Ru(bpy)32+/TPrA system on microfluidic chips using a two-electrode system and the TP excitation model has been demonstrated. This suggests that ECL chips without a RE have broad potential for the rapid and sensitive detection of multiple targets.

An Exciplex-Based Light-Emission Pathway for Solution-State Electrochemiluminescent Devices

Electrochemiluminescence (ECL) allows the design of unique light-emitting devices that use organic semiconductors in a liquid or gel state, which allows for simpler and more sustainable device fabrication and facilitates unconventional device form-factors. Compared to solid-state organic LEDs, ECL devices (ECLDs) have attracted less attention due to their currently much lower performance. ECLD operation is typically based on an annihilation pathway that involves electron transfer between reduced and oxidized luminophore species; the intermediate radical ions produced during annihilation dramatically reduce device stability. Here, the effects of radical ions are mitigated by an exciplex formation pathway and a remarkable improvement in luminance, luminous efficacy, and operational lifetime is demonstrated. Electron donor and acceptor molecules are dissolved at high concentrations and recombined as an exciplex upon their oxidization/reduction. The exciplex then transfers its energy to a nearby dye, allowing the dye to emit light without undergoing oxidation/reduction. Furthermore, the application of a mesoporous TiO2 electrode increases the contact area and hence the number of molecules participating in ECL , thereby obtaining devices with a very high luminance of 3790 cd m-2 and a 30-fold improved operational lifetime. This study paves the way for the development of ECLDs into highly versatile light sources.

Self-Enhanced Electrochemiluminescence Imaging System Based on the Accelerated Generation of ROS under Ultrasound

Electrochemiluminescence (ECL) imaging, as an optical technology, has been developed at full tilt in the field of life science and nanomaterials. However, the relatively low ECL intensity or the high co-reactant concentration needed in the electrochemical reaction blocks its practical application. Here, we developed an ECL imaging system based on the rGO-TiO_2-x composite material, where the co-reactant, reactive oxygen species (ROS), is generated in situ under the synergetic effect of of ultrasound (US) and electric irradiation. The rGO-TiO_2-x composites facilitate the separation of electron (e^-) and hole (h⁺) pairs and inhibit recombination triggered by external US irradiation due to the high electroconductivity of rGO and oxygen-deficient structures of TiO₂, thus significantly boosting ROS generation. Furthermore, the increased defects on rGO accelerate the electron transfer rate, improving the electrocatalytic performance of the composite and forming more ROS. This high ultrasonic-electric synergistic efficacy is demonstrated through the enhancement of photon emission. Compared with the luminescence intensity triggered by US irradiation and electric field, an enhancement of ∼20-fold and 10-fold of the US combined with electric field-triggered emission is observed from this composite. Under the optimized conditions, using dopamine (DA) as a model target, the sensitivity of the US combined ECL strategy for detection of DA is two orders of magnitude higher than that of the ECL method. The successful detection of DA at low concentrations makes us believe that this strategy provides the possibility of applying ECL imaging for cellular single-molecule analysis and cancer therapy.

Fabrication of a simple 3D-printed microfluidic device with embedded electrochemiluminescence detection for rapid determination of sibutramine in dietary supplements

The design and fabrication of a simple 3D-printed platform with embedded electrochemiluminescence (ECL) detection for sibutramine determination is described. The microfluidic platform was fabricated by the fused deposition 3D-printing technique with polylactic acid filament, facilitated by computer-aided design (CAD). A three-electrode system was integrated into the device using graphene carbon paste as a working electrode, Ag/AgCl wire as a reference, and a graphite rod as a counter electrode. A further modification was carried out by applying bimetallic Au-Pt nanoparticle-supported multi-walled carbon nanotubes (MWCNT-Au-Pt) on the working electrode surface to enhance the electrocatalytic performance by exploiting the unique properties of nanomaterials. The analytical feasibility of the CAD-ECL sensor was tested through its application for the determination of sibutramine in dietary supplements. Under the optimized conditions, based on the enhancing effect of luminol emission, the device exhibited a linear calibration curve of the logarithmic sibutramine concentration versus ECL intensity in the range 5 × 10^-3 to 1 ng mL^-1. The limit of detection was 3 pg mL^-1 with a relative standard deviation of 1.7% (n = 15). The 3D-printed prototype can be successfully applied to a small-scale analysis in a simple and cost-effective approach.

The Use of Sensors in Blood-Brain Barrier-on-a-Chip Devices: Current Practice and Future Directions

The application of lab-on-a-chip technologies in in vitro cell culturing swiftly resulted in improved models of human organs compared to static culture insert-based ones. These chip devices provide controlled cell culture environments to mimic physiological functions and properties. Models of the blood-brain barrier (BBB) especially profited from this advanced technological approach. The BBB represents the tightest endothelial barrier within the vasculature with high electric resistance and low passive permeability, providing a controlled interface between the circulation and the brain. The multi-cell type dynamic BBB-on-chip models are in demand in several fields as alternatives to expensive animal studies or static culture inserts methods. Their combination with integrated biosensors provides real-time and noninvasive monitoring of the integrity of the BBB and of the presence and concentration of agents contributing to the physiological and metabolic functions and pathologies. In this review, we describe built-in sensors to characterize BBB models via quasi-direct current and electrical impedance measurements, as well as the different types of biosensors for the detection of metabolites, drugs, or toxic agents. We also give an outlook on the future of the field, with potential combinations of existing methods and possible improvements of current techniques.

Recent Advances in Single Cell Analysis by Electrochemiluminescence

Understanding biological mechanisms operating in cells is one of the major goals of biology. Since heterogeneity is the fundamental property of cellular systems, single cell measurements can provide more accurate information about the composition, dynamics, and regulatory circuits of cells than population-averaged assays. Electrochemiluminescence (ECL), the light emission triggered by electrochemical reactions, is an emerging approach for single cell analysis. Numerous analytes, ranging from small biomolecules such as glucose and cholesterol, proteins and nucleic acids to subcellular structures, have been determined in single cells by ECL, which yields new insights into cellular functions. This review aims to provide an overview of research progress on ECL principles and systems for single cell analysis in recent years. The ECL reaction mechanisms are briefly introduced, and then the advances and representative works in ECL single cell analysis are summarized. Finally, outlooks and challenges in this field are addressed.

Controllable Enhanced Ru(bpy)32+ Electrochemiluminescence Detection Systems Based on Eu@MOF253@AuNPs/GCE for the Sensitive Detection of Carbaryl in Food

In this study, an electrochemiluminescence detection system for the sensitive detection of carbaryl was constructed based on the dual identification of Eu@MOF253, which has a recognition effect on carbaryl, and the electrochemiluminescence system of Ru(bpy)₃²⁺/S₂O₈^2-, which can react with carbaryl in a redox reaction. This method not only overcame the weakness of the electrochemiluminescence instability of the Ru(bpy)₃²⁺/S₂O₈^2- system but also changed the sensitivity of the sensing detection system to the target by adjusting the concentration of Ru(bpy)₃²⁺ and then proposed a detection strategy with a controllable detection range. After analyzing the electrochemiluminescence signal change mechanism of this system and optimizing the detection conditions, it was concluded that the strategy has good linear detection of carbaryl in the range of 1-1000 and 0.02-0.3 μg L^-1, and the detection limits were 0.058 and 0.014 μg L^-1. Finally, the strategy was also successfully applied to the detection of actual samples.

Enhanced Cathodic Electrochemiluminescence of Luminol on Iron Electrodes

Electrochemiluminescence (ECL) behavior of luminol derivative was investigated in reduction on different electrode materials. We found that luminol and its widely used L-012 derivative, emitting at physiological pH values, exhibit strong cathodic ECL emission on iron and stainless steel electrodes with hydrogen peroxide, whereas no ECL signal was observed with other classic electrode materials (Au, Pt, and C). On a Ni electrode, a low cathodic ECL signal was observed. This points out to the essential role of iron-containing materials to enhance the cathodic ECL emission. Under the reported conditions, the cathodic ECL signal of L-012 is comparable to the classically used anodic ECL emission. Thus, dual bright ECL emissions with L-012 were obtained simultaneously in oxidation and in reduction on iron materials as imaged in a wireless bipolar electrochemistry configuration. Such an ECL system generating light emission concomitantly in oxidation and in reduction is extremely rare and it opens appealing (bio)analytical and imaging applications, in biosensing, remote detection, bipolar ECL analysis, and ECL-based cell microscopy.

Recent Progress in Electrochemical Immunosensors

Biosensors used for medical diagnosis work by analyzing physiological fluids. Antibodies have been frequently used as molecular recognition molecules for the specific binding of target analytes from complex biological solutions. Electrochemistry has been introduced for the measurement of quantitative signals from transducer-bound analytes for many reasons, including good sensitivity. Recently, numerous electrochemical immunosensors have been developed and various strategies have been proposed to detect biomarkers. In this paper, the recent progress in electrochemical immunosensors is reviewed. In particular, we focused on the immobilization methods using antibodies for voltammetric, amperometric, impedimetric, and electrochemiluminescent immunosensors.

Technological Advancements for the Detection of Antibiotics in Food Products

Antibiotics, nowadays, are not only used for the treatment of human diseases but also used in animal and poultry farming to increase production. Overuse of antibiotics leads to their circulation in the food chain due to unmanaged discharge. These circulating antibiotics and their residues are a major cause of antimicrobial resistance (AMR), so comprehensive and multifaceted measures aligning with the One Health approach are crucial to curb the emergence and dissemination of antibiotic resistance through the food chain. Different chromatographic techniques and capillary electrophoresis (CE) are being widely used for the separation and detection of antibiotics and their residues from food samples. However, the matrix present in food samples interferes with the proper detection of the antibiotics, which are present in trace concentrations. This review is focused on the scientific literature published in the last decade devoted to the detection of antibiotics in food products. Various extraction methods are employed for the enrichment of antibiotics from a wide variety of food samples; however, solid-phase extraction (SPE) techniques are often used for the extraction of antibiotics from food products and biological samples. In addition, this review has scrutinized how changing instrumental composition, organization, and working parameters in the chromatography and CE can greatly impact the identification and quantification of antibiotic residues. This review also summarized recent advancements in other detection methods such as immunological assays, surface-enhanced Raman spectroscopy (SERS)-based assays, and biosensors which have emerged as rapid, sensitive, and selective tools for accurate detection and quantification of traces of antibiotics.

Mapping the Distribution of Potential Gradient in Bipolar Electrochemical Systems through Luminol Electrochemiluminescence Imaging

Bipolar electrochemistry has been regarded as a powerful and sustainable electrochemical process for the synthesis of novel functional materials. The appealing features of this electrochemical technology, such as the wireless nature of the bipolar electrode (BPE) and the possibility to drive simultaneously electrochemical reactions on multiple BPEs placed in the same electrochemical cell, together with the possibility to change the shape and positioning of the driving electrodes, give significant freedom to design reaction systems. Nevertheless, the cell geometry dramatically affects the distribution and intensity of the potential gradient generated on the BPE surface and its monitoring is hampered due to the wireless nature of the BPE. In the present study, we propose the use of electrochemiluminescence (ECL) as an electrochemical imaging technique to map the distribution of potential gradient in bipolar electrochemical cells with different geometries. The proposed approach exploits the strong ECL emission of luminol/hydrogen peroxide (H₂O₂) system generated at the anodic pole of the BPE, when the total applied voltage (E_tot) is strong enough to trigger the electrochemical reaction. Since luminol ECL emission is rather intense and relatively stable, the evolution of the potential distribution as a function of E_tot can be monitored using a digital camera, allowing the elucidation of the potential distribution profile in every bipolar configuration. The suggested approach represents a valuable and reliable method to map the potential gradient in bipolar electrochemical systems and can be readily employed in every type of bipolar configuration.

Electrochemiluminescence imaging of respiratory activity of cellular spheroids using sequential potential steps

The respiratory activity of cultured cells can be electrochemically monitored using scanning electrochemical microscopy (SECM) with high spatial resolution. However, in SECM, the electrode takes a long time to scan, limiting simultaneous measurements with large biological samples such as cell spheroids. Therefore, for rapid electrochemical imaging, a novel strategy is needed. Herein, we report electrochemiluminescence (ECL) imaging of spheroid respiratory activity for the first time using sequential potential steps. L-012, a luminol analog, was used as an ECL luminophore, and H₂O₂, a sensitizer for ECL of L-012, was generated by the electrochemical reduction of dissolved O₂. The ECL imaging visualized spheroid respiratory activity-evidenced by ECL suppression-corresponding to O₂ distribution around the spheroids. This method enabled the time-lapse imaging of respiratory activity in multiple spheroids with good spatial resolution comparable to that of SECM. Our work provides a promising high-throughput imaging strategy for elucidating spheroid cellular dynamics.

N-methyl-d-aspartate receptor hyperfunction contributes to d-serine-mediated renal insufficiency

Glutamate N-methyl-d-aspartate receptor (NMDAR) hyperfunction is known to contribute to acute renal failure due to ischemia-reperfusion and endotoxemia. d-Serine is a coagonist for NMDAR activation, but whether NMDARs play a role in d-serine-mediated nephrotoxicity remains unclear. Here, we demonstrate that NMDAR blockade ameliorated d-serine-induced renal injury. In NMDAR-expressing LLC-PK1 cells, which were used as a proximal tubule model, d-serine but not l-serine induced cytotoxicity in a dose-dependent manner, which was abrogated by the selective NMDAR blockers MK-801 and AP-5. Time-dependent oxidative stress, evidenced by gradually increased superoxide and H2O2 production, was associated with d-serine-mediated cytotoxicity; these reactive oxygen species could be alleviated not only after NMDAR inhibition but also by NADPH oxidase (NOX) inhibition. Activation of protein kinase C (PKC)-δ and PKC-ζ is a downstream signal for NMDAR-mediated NOX activation because PKC inhibition diminishes the NOX activity that is induced by d-serine. Renal injury was further confirmed in male Wistar rats that intraperitoneally received d-serine but not l-serine. Peak changes in glucosuria, proteinuria, and urinary excretion of lactate dehydrogenase and malondialdehyde were found after 24 h of treatment. Persistent tubular damage was observed after 7 days of treatment. Cotreatment with the NMDAR blocker MK-801 for 24 h abolished d-serine-induced functional insufficiency and tubular damage. MK-801 attenuated renal superoxide formation by lowering NOX activity and protein upregulation of NOX4 but not NOX2. These results reveal that NMDAR hyperfunction underlies d-serine-induced renal injury via the effects of NOX4 on triggering oxidative stress.NEW & NOTEWORTHY Ionotropic N-methyl-d-aspartate receptors (NMDARs) are not only present in the nervous system but also expressed in the kidney. Overstimulation of renal NMDARs leads to oxidative stress via the signal pathway of calcium/protein kinase C/NADPH oxidase in d-serine-mediated tubular cell damage. Intervention of NMDAR blockade may prevent acute renal injury caused by d-serine.

Antihormone treatment differentially regulates PSA secretion, PSMA expression and 68Ga-PSMA uptake in LNCaP cells

Background

In recent years, a variety of innovative therapeutics for castration-resistant prostate cancer have been developed, including novel anti-androgenic drugs, such as abiraterone or VPC-13566. Therapeutic monitoring of these pharmaceuticals is performed either by measuring PSA levels in serum or by imaging. PET using PSMA ligands labeled with Fluor-18 or Gallium-68 is the most sensitive and specific imaging modality for detection of metastases in advanced prostate cancer. To date, it remains unclear how PSMA expression is modulated by anti-hormonal treatment and how it correlates with PSA secretion.

Methods

We analyzed modulation of PSMA-mRNA and protein expression, ⁶⁸Ga–PSMA uptake and regulation of PSA secretion by abiraterone or VPC-13566 in LNCaP cells in vitro.

Results

We found that abiraterone and VPC-13566 upregulate PSMA protein and mRNA expression but block PSA secretion in LNCaP cells. Both anti-androgens also enhanced ⁶⁸Ga–PSMA uptake normalized by the number of cells, whereas abiraterone and VPC-13566 reduced ⁶⁸Ga–PSMA uptake in total LNCaP monolayers treated due to cell death.

Conclusion

Our data indicate that PSA secretion and PSMA expression are differentially regulated upon anti-androgen treatment. This finding might be important for the interpretation of ⁶⁸Ga–PSMA PET images in monitoring therapies with abiraterone and VPC-13566 in prostate cancer patients, but needs to be validated in vivo.

Miniaturized Electrochemiluminescence Platform With Laser-Induced Graphene Electrodes for Multiple Biosensing

The present work demonstrates a miniaturized 3D printed Electrochemiluminescence (ECL) sensing platform with Laser-Induced Graphene (LIG) based Open Bipolar Electrodes (OBEs). To fabricate OBEs, polyimide (PI) substrate has been used as it provides properties like low-cost fabrication, high selectivity, great stability, easy reproducibility, cost-effectiveness and rapid prototyping. Moreover, graphene can be created on PI in a single step during the ablation of the CO₂ laser. Android smartphone was efficiently used to sense ECL signals as well as to drive the required voltage to the OBEs. With the optimized parameters, the imaging system was successfully used to detect Hydrogen Peroxide (H₂ O₂) with a linear range of 1 [Formula: see text] to [Formula: see text] and detection of limit (LOD) [Formula: see text] (R² = 0.9449, n = 3). In addition, the detection of glucose has been carried out with a linear range of [Formula: see text] to [Formula: see text] and detection of limit (LOD) [Formula: see text] (R² = 0.9875, n = 3). Further, real samples were tested to manifest the workability of the platform for random samples. Overall, the developed low-cost, rapidly realized and the miniaturized system can be used in many biomedical applications, environmental monitoring and point-of-care testings.

Light-Emitting Probes for Labeling Peptides

Peptides are versatile biopolymers composed of 2-100 amino acid residues that present a wide range of biological functions and constitute potential therapies for numerous diseases, partly due to their ability to penetrate cell membranes. However, their mechanisms of action have not been fully elucidated due to the lack of appropriate tools. Existing light-emitting probes are limited by their cytotoxicity and large size, which can alter peptide structure and function. Here, we describe the available fluorescent, bioluminescent, and chemiluminescent probes for labeling peptides, with a focus on minimalistic options.

Electrochemiluminescence Enhancement and Particle Structure Stabilization of Polymer Nanoparticle by Doping Anionic Polyelectrolyte and Cationic Polymer Containing Tertiary Amine Groups and Its Highly Sensitive Immunoanalysis

A doped polymer nanoparticle (dPNP) of electrochemiluminescence (ECL) was prepared via doping the anionic polyelectrolyte polyacrylic acid (PAA) and the cationic polymer poly-ethyleneimine (PEI) into the polymer nanoparticle (PNP), which was self-assembled by Ru(bpy)32+ derivative-grafted PAA (PAA–Ru) with both cations and anions. The good electrical conductivity of the doped polyelectrolyte PAA enhanced the ECL intensity of PNP to 109.1%, and the involvement of a large number of tertiary amine groups of the doped PEI further enhanced that to 127.3%; meanwhile, doping low-molecular-weight PEI into PNP, while simultaneously doping high-molecular-weight PAA, avoided the precipitation of PAA and PEI, due to interaction of the two oppositely charged polymers; and these also made the self-assembly procedure more effective and the nanoparticle structure more stable than PNP and also led to the production of rich residual PAA chains on the surface of dPNP. The storage results showed that the average hydrated particle diameter kept almost constant (197.5–213.1 nm) during 15-day storage and that the nanoparticles have rich surface charge of −11.47 mV (zeta potential), well suspension stability and good dispersity without detectable aggregation in the solution during the storage. Therefore, the nanoparticle is quite suitable for the antibody labeling, immunoassay and the storage. As a result, a high-sensitive ECL immunoassay approach with good precision, accuracy and selectivity was established and an ultra-low detection limit of 0.049 pg mL−1 (S/N = 3) for magnetic bead-based detection of Hepatitis B surface antigen was observed.

Highly sensitive bioaffinity electrochemiluminescence sensors: Recent advances and future directions

Electrogenerated chemiluminescence (also called electrochemiluminescence and abbreviated ECL) has attracted much attention in various fields of analysis due to the potential remarkably high sensitivity, extremely wide dynamic range and excellent controllability. Electrochemiluminescence biosensor, by taking the advantage of the selectivity of the biological recognition elements and the high sensitivity of ECL technique was applied as a powerful analytical device for ultrasensitive detection of biomolecule. In this review, we summarize the latest sensing applications of ECL bioanalysis in the field of bio affinity ECL sensors including aptasensors, immunoassays and DNA analysis, cytosensor, molecularly imprinted sensors, ECL resonance energy transfer and ratiometric biosensors and give future perspectives for new developments in ECL analytical technology. Furthermore, the results herein discussed would demonstrate that the use of nanomaterials with unique chemical and physical properties in the ECL biosensing systems is one of the most interesting research lines for the development of ultrasensitive electrochemiluminescence biosensors. In addition, ECL based sensing assays for clinical samples analysis and medical diagnostics and developing of immunosensors, aptasensors and cytosensor for this purpose is also highlighted.

Electrogenerated Chemiluminescence for Chronopotentiometric Sensors

We introduce here a general strategy to read out chronopotentiometric sensors by electrogenerated chemiluminescence (ECL). The potentials generated in chronopotentiometry in a sample compartment are used to control the ECL in a separate detection compartment. A three-electrode cell is used to monitor the concentration changes of the analyte, while the luminol-H₂O₂ system is responsible for ECL. The principle was shown to be feasible by theoretical simulations, indicating that the sampled times at a chosen potential, rather than traditional transition times, similarly give linear behavior between concentration and the square root of sampled time. With the help of a voltage adapter, the experimental combination between chronopotentiometry and ECL was successfully implemented. As an initial proof of concept, the ferro/ferricyanide redox couple was investigated. The square root of time giving maximum light output changed linearly with ferrocyanide concentration in the range from 0.70 to 4.81 mM. The method was successfully applied to the visual detection of carbonate alkalinity from 0.06 to 0.62 mM using chronopotentiometry at an ionophore-based hydrogen ion-selective membrane electrode. The measurements of carbonate in real samples including river water and commercial mineral water were successfully demonstrated.

A molecularly imprinted sensor with enzymatic enhancement of electrochemiluminescence of quantum dots for ultratrace clopyralid determination

A new molecularly imprinted polymer electrochemiluminescence (ECL) sensor was developed for the detection of clopyralid (CPD) based on enzyme-biocatalyzed amplification. CdTe quantum dots were immobilized on the surface of an electrode by reaction with p-aminothiophenol preadsorbed on the electrode. Then a molecularly imprinted film was formed by electrochemical polymerization of o-phenylenediamine in the presence of CPD on the CdTe-modified gold electrode. During the analytical cycle, horseradish peroxidase (HRP)-labeled CPD was replaced by CPD in the sample. The amount of HRP on the molecularly imprinted polymer electrode decreased, and then less H₂O₂ was catalytically decomposed. Subsequently, the ECL intensity of the CdTe-H₂O₂ system was enhanced. There was a good linear relationship between ECL intensity and the concentration of CPD in the range from 2.0 × 10^-11 to 2.5 × 10^-10 mol/L and in the range from 2.5 × 10^-10 to 3.5 × 10^-8 mol/L. The detection limit was 4.1 × 10^-12 mol/L. The sensor was applied to determine CPD in vegetable samples. Graphical abstract A molecularly imprinted electrochemiluminescence sensor was fabricated for ultratrace clopyralid determination. The sensitivity was significantly improved with the enhancement of the ECL intensity of quantum dot via the enzymatic reaction of HRP.

A comprehensive review on nano-molybdenum disulfide/DNA interfaces as emerging biosensing platforms

The development of nucleic acid-based portable platforms for the real-time analysis of diseases has attracted considerable scientific and commercial interest. Recently, 2D layered molybdenum sulfide (2D MoS₂ from here on) nanosheets have shown great potential for the development of next-generation platforms for efficient signal transduction. Through combination with DNA as a biorecognition medium, MoS₂ nanostructures have opened new opportunities to design and construct highly sensitive, specific, and commercially viable sensing devices. The use of specific short ssDNA sequences like aptamers has been proven to bind well with the unique transduction properties of 2D MoS₂ nanosheets to realize aptasensing devices. Such sensors can be operated on the principles of fluorescence, electro-cheumuluminescence, and electrochemistry with many advantageous features (e.g., robust biointerfacing through various conjugation chemistries, facile sensor assembly, high stability with regard to temperature/pH, and high affinity to target). This review encompasses the state of the art information on various design tactics and working principles of MoS₂/DNA sensor technology which is emerging as one of the most sought-after and valuable fields with the advent of nucleic acid inspired devices. To help achieve a new milestone in biosensing applications, great potential of this emerging technique is described further with regard to sensitivity, specificity, operational convenience, and versatility.

Improving ruthenium-based ECL through nonionic surfactants and tertiary amines

The influence of surfactants and coreactants on Ru(bpy)₃²⁺ electrogenerated chemiluminescence (ECL) was investigated comparatively.

An electrochemiluminescence cloth-based biosensor with smartphone-based imaging for detection of lactate in saliva

An electrochemiluminescence cloth-based biosensor with smartphone-based imaging is firstly proposed, and is applied for facile detection of lactate in saliva.

A review of electrogenerated chemiluminescent biosensors for assays in biological matrices

Electrogenerated chemiluminescence (ECL) is the production of light via electron transfer reactions between electrochemically produced reagents. ECL-based biosensors use specific biological interactions to recognize an analyte and produce a luminescent signal. Biosensors fabricated with novel biorecognition species have increased the number of analytes detected. Some of these analytes include peptides, cells, enzymes and nucleic acids. ECL biosensors are selective, simple, sensitive and have low detection limits. Traditional methods use ruthenium complexes or luminol to generate ECL. Nanomaterials can be incorporated into ECL biosensors to improve efficiency, but also represent a new class of ECL emitters. This article reviews the application of ruthenium complex, luminol and nanomaterial-based ECL biosensors to making measurements in biological matrices over the past 4 years.