A Chemical Redox Cycling-Based Dual-Mode Biosensor for Self-Powered Photoelectrochemical and Colorimetric Assay of Heat Shock Protein.

To advance the biological understanding of heat shock protein (HSP) in different types of cancers, it is crucial to achieve its accurate determination. Herein, a dual-mode self-powered photoelectrochemical (PEC) and colorimetric platform was proposed by integrating enzymatic catalysis and a chemical redox cycling amplification strategy. In this system, ascorbic acid (AA), as the signal reporter for PEC and colorimetric assay, can be regenerated during the tris(2-carboxyethyl) phosphine-mediated chemical redox cycling process.

Etching of Ag nanoparticles triggered bidirectional regulation for electrochemiluminescence ratiometric immunoassay.

A highly efficient ratiometric electrochemiluminescence (ECL) immunoassay was explored by bidirectionally regulating the ECL intensity of two luminophors. The immunoassay was conducted in a split-type mode consisting of an ECL detection procedure and a sandwich immunoreaction. The ECL detection was executed using a dual-disk glassy carbon electrode modified with two potential-resolved luminophors (g-CN-Ag and Ru-MOF-Ag nanocomposites), and the sandwich immunoreaction using glucose oxidase (GOx)-modified SiO nanospheres as labels was carried out in a 96-well plate.

Chemical-chemical redox cycling for improving the sensitivity of the fluorescent assay: A proof-of-concept towards DNA methylation detection.

Ultrasensitive analytical methods are still urgent for the discovery of trace level biomarkers and the early clinical diagnosis of disease. In this work, an ultrasensitive universal sensing platform was constructed by integrating fluorescent assay with chemical-chemical redox cycling signal amplification strategy. Using Ru@SiO nanoparticles wrapped by MnO nanosheets (Ru@SiO@MnO) as fluorescent probe, the chemical-chemical redox cycling system was conducted upon ascorbic acid (AA) and tris(2-carboxyethyl)phosphine (TCEP) as reductants and MnO nanosheets as oxidant.

Cu-MOFs/GOx Bifunctional Probe-Based Synergistic Signal Amplification Strategy: Toward Highly Sensitive Closed Bipolar Electrochemiluminescence Immunoassay.

A closed bipolar electrochemiluminescence (BP-ECL) platform for sensitive prostate specific antigen (PSA) detection was proposed based on a novel synergistic signal amplification strategy. Specifically, glucose oxidase-loaded Cu-based metal-organic frameworks (Cu-MOFs/GOx) as bifunctional probes were bridged on the anodic interface with the target PSA as the intermediate unit. In virtue of the large loading capacity of Cu-MOFs, a large amount of a co-reactant, i.

Bipolar Electrochemistry - A Powerful Tool for Micro/Nano-Electrochemistry.

The understanding of areas for "classical" electrochemistry (including catalysis, electrolysis and sensing) and bio-electrochemistry at the micro/nanoscale are focus on the continued performance facilitations or the exploration of new features. In the recent 20 years, a different mode for driving electrochemistry has been proposed, which is called as bipolar electrochemistry (BPE). BPE has garnered attention owing to the interesting properties: (i) its wireless nature facilitates electrochemical sensing and high throughput analysis; (ii) the gradient potential distribution on the electrodes surface is a useful tool for preparing gradient surfaces and materials.

Liposome-assisted chemical redox cycling strategy for advanced signal amplification: A proof-of-concept toward sensitive electrochemiluminescence immunoassay.

This work presents a novel signal amplification strategy for electrochemiluminescence (ECL) biosensor based on liposome-assisted chemical redox cycling for in situ formation of Au nanoparticles (Au NPs) on TiO nanotubes (TiO NTs) electrode. The system was exemplified by ascorbic acid (AA)-loaded liposome, the redox cycling of AA utilizing tris (2-carboxyethyl) phosphine (TCEP) as reductant, and the use of Au nanoclusters (Au NCs)/TiO NTs as working electrode to implement the ECL detection of prostate specific antigen (PSA). Specifically, the AA-loaded liposomes were used as tags to label the captured PSA through a sandwich immunoreaction.

Formation of BiMoO-BiS Heterostructure: A Proof-Of-Concept Study for Photoelectrochemical Bioassay of l-Cysteine.

A novel signal-increased photoelectrochemical (PEC) biosensor for l-cysteine (L-Cys) was proposed based on the BiMoO-BiS heterostructure formed on the indium-tin oxide (ITO) electrode. To fabricate the PEC biosensor, BiMoO nanoparticles were prepared by a hydrothermal method and coated on a bare ITO electrode. When L-Cys existed, BiS was formed on the interface of the BiMoO/ITO electrode by a chemical displacement reaction.

HO-activated independently bidirectional regulation for a sensitive and accurate electrochemiluminescence ratiometric analysis.

Potential-resolved electrochemiluminescence (ECL) ratiometric analysis has become a research hotspot in bioassays by virtue of its good accuracy, versatility and specificity. Current ECL ratiometry mainly focuses on the competition for the co-reactant or quantitative analysis using a variable signal and a changeless signal; the disorganized change or small difference between the two signals may affect the accuracy and sensitivity of detection. In this study, we have developed a novel ECL ratiometric sensor based on the bidirectional regulation of two independent co-reaction systems by HO.

Dual-wavelength electrochemiluminescence ratiometry for hydrogen sulfide detection based on Cd-doped g-CN nanosheets.

Herein, a novel and facile dual-wavelength ratiometric electrochemiluminescence-resonance energy transfer (ECL-RET) sensor for hydrogen sulfide (HS) detection was constructed based on the interaction between S and Cd-doped g-CN nanosheets (NSs). Cd-doped g-CN NSs exhibited a strong ECL emission at 435 nm. In the presence of HS, CdS was formed on g-CN NSs by the adsorption of S and Cd, generating another ECL emission at 515 nm.

A membraneless self-powered photoelectrochemical biosensor based on BiS/BiPO heterojunction photoanode coupling with redox cycling signal amplification strategy.

The photoelectrochemical (PEC) self-powered system has attracted great attention in disease detection. The determination of a simple and efficient approach for disease-related biomarkers is highly interesting and appealing. Herein, an ingenious visible light-induced membraneless self-powered PEC biosensing platform was constructed, integrating a signal amplification strategy for ultrasensitive split-type PEC bioanalysis.

A novel split-type photoelectrochemical immunosensor based on chemical redox cycling amplification for sensitive detection of cardiac troponin I.

Photoelectrochemical (PEC) immunoassay is a burgeoning and promising bioanalytical method. However, the practical application of PEC still exist some challenges such as the inevitable damage of biomolecules caused by the PEC system and the unsatisfactory sensitivity for biomarkers with low abundance in real sample. To solve the problems, we integrated the cosensitized structure of Ag2S/ZnO nanocomposities as photoelectrode with photogenerated hole-induced chemical redox cycling amplification (CRCA) strategy to develop a split-type PEC immunosensor for cardiac troponin I (cTnI) with high sensitivity.

Photogenerated Hole-Induced Chemical-Chemical Redox Cycling Strategy on a Direct -Scheme BiS/BiMoO Heterostructure Photoelectrode: Toward an Ultrasensitive Photoelectrochemical Immunoassay.

To achieve high sensitivity for biomolecule detection in photoelectrochemical (PEC) bioanalysis, the ideal photoelectrode and ingenious signaling mechanism play crucial roles. Herein, the feasibility of the photogenerated hole-induced chemical-chemical redox cycling amplification strategy on a -scheme heterostructure photoelectrode was validated, and the strategy toward enhanced multiple signal amplification for advanced PEC immunoassay application was developed. Specifically, a direct Z-scheme BiS/BiMoO heterostructure was synthesized via a classic hydrothermal method and served as a photoelectrode for the signal response.

Liposome-assisted enzyme catalysis: toward signal amplification for sensitive split-type electrochemiluminescence immunoassay.

Developing an efficient signal amplification strategy is very important to improve the sensitivity of bioanalysis. In this paper, a liposome-assisted enzyme catalysis signal amplification strategy was developed for electrochemiluminescence (ECL) immunoassay of prostate specific antigen (PSA) in a split-type mode. The sandwich immunoreaction occurred in a 96-well plate, and glucose oxidase (GOx) encapsulated and antibody-modified liposomes were used as labels.

Chemical-chemical redox cycling amplification strategy in a self-powered photoelectrochemical system: a proof of concept for signal amplified photocathodic immunoassay.

A chemical-chemical redox cycling amplification strategy was introduced into a photocathodic immunosensing system. To prove the applicability of the method, a novel self-powered photochemical system by integrating the photoanode and photocathode was designed for protein analysis.

A novel chemiluminescence imaging immunosensor for prostate specific antigen detection based on a multiple signal amplification strategy.

A novel chemiluminescence (CL) imaging platform was constructed for prostate specific antigen (PSA) detection in a multiple signal amplifying manner. To construct the platform, the primary antibody for PSA was firstly immobilized on a O-ring area of a glass slide for recognizing the PSA. The horseradish peroxidase (HRP) and the secondary antibody of PSA (Ab) functionalized Au NPs (HRP-Au NPs-Ab) were modified on the platform through immunoreaction between PSA and Ab.

A ternary CdS@Au-g-CN heterojunction-based photoelectrochemical immunosensor for prostate specific antigen detection using graphene oxide-CuS as tags for signal amplification.

Photoactive materials with high photo-electron transfer efficiency and stable signal output hold a key role in constructing the photoelectrochemical (PEC) biosensing systems. In this study, the ternary CdS@Au-g-CN heterojunction was first prepared and characterized, and its application in PEC bioanalysis was explored. The gold nanoparticles sandwiched between CdS and g-CN, acting as both plasmonic photosensitizer and electron relay, significantly boosted the light absorption and accelerated the charge transfer from g-CN to CdS, both of which contributed to the enhancement of photoelectric conversion efficiency.

Recent progress of heterostructure-based photoelectrodes in photoelectrochemical biosensing: a mini review.

Photoelectrochemical (PEC) biosensing has received increasing attention due to its great potential in the analysis of biomarkers. The performance of a PEC biosensor depends largely on photosensitive materials. The photoactive materials with excellent properties are of great importance to realize advanced PEC bioassays.

Copper ion modified graphitic CN nanosheets enhanced luminol-HO chemiluminescence system: Toward highly selective and sensitive bioassay of HS in human plasma.

A high-efficient chemiluminescence (CL) platform for highly selective and sensitive HS detection was constructed on the basis of the quenching effect of S on the copper ion modified graphitic carbon nitride nanosheets (Cu-g-CN NSs) enhanced luminol-HO system. Cu-g-CN NSs with horseradish peroxidase-like catalytic activity were prepared and provide a great improvement for luminol-HO system. The presence of S induced the formation of CuS precipitate on g-CN NSs surface.

A potentiometric resolved photoelectrochemical system based on CdS nanowires and SnNbO nanosheets: a case application for dual biomarker analysis.

A potentiometric resolved photoelectrochemical (PEC) system based on CdS nanowires and SnNb2O6 nanosheets was developed. To prove the applicability of this system in PEC multi-biomarker analysis, a label free PEC immunosensor for two cardiac biomarkers, myoglobin and cardiac troponin I, was constructed.

Reduced graphene oxide-gold nanoparticles-catalase-based dual signal amplification strategy in a spatial-resolved ratiometric electrochemiluminescence immunoassay.

A novel spatial-resolved electrochemiluminescent (ECL) ratiometry for cardiac troponin I (cTnI) analysis was developed using resonance energy transfer (RET) and a coreactant consumption strategy for signal amplification. Specifically, the spatial-resolved dual-disk glassy carbon electrodes were modified with CdS nanowires (CdS NWs) and luminol-gold nanoparticles (L-Au NPs) as potential-resolved ECL emitters, respectively. After stepwise immobilization of anti-cTnI and bovine serum albumin on the dual-disk electrodes, the CdS NWs-based electrode, with varied concentrations of cTnI, was used to provide a working signal, whereas the L-Au NPs-based electrode, with a fixed amount of cTnI, was employed to provide the reference signal.

CdS:Mn-sensitized 2D/2D heterostructured g-CN-MoS with excellent photoelectrochemical performance for ultrasensitive immunosensing platform.

The exploration of advanced photoactive materials with fine photoelectrochemical (PEC) performance is always the hot subject in PEC bioanalysis. Herein, Mn-doped CdS nanocrystals (CdS:Mn)-sensitized 2D/2D heterostructured g-CN-MoS was prepared and served as photoactive matrix of PEC sensing platform for myoglobin (Myo) detection using CuO nanoparticles labeled anti-Myo (anti-Myo-CuO) conjugates as signal amplification tags. The heterostructured g-CN-MoS could effectively promote the electron transfer and evidently restrain the recombination of electron-hole pairs, producing the high photocurrent response.

A novel nitrogen and sulfur co-doped carbon dots-HO chemiluminescence system for carcinoembryonic antigen detection using functional HRP-Au@Ag for signal amplification.

A novel nitrogen and sulfur co-doped carbon dots (NS-CDs)-HO chemiluminescence (CL) system was developed to detect carcinoembryonic antigen (CEA) by taking advantage of dual-signal amplification of functional Au@Ag nanoparticles (NPs) nanoprobes. Horseradish peroxidase (HRP) and the complementary DNA were co-immobilized onto Au@Ag NPs surface to shape the functional nanoprobes (HRP-Au@Ag-cDNA) for signal amplification. In this proposal, HRP-Au@Ag-cDNA was specifically hybridized with CEA aptamer-functionalized magnetic beads to form the double-strand hybridization nanocomposites (HRP-Au@Ag-dsDNA-MB).

Ru(NH)/Ru(NH)-Mediated Redox Cycling: Toward Enhanced Triple Signal Amplification for Photoelectrochemical Immunoassay.

Herein we report an effective Ru(NH)/Ru(NH)-mediated photoelectrochemical-chemical-chemical (PECCC) redox cycling amplification (RCA) strategy toward enhanced triple signal amplification for advanced split-type PEC immunoassay application. Specifically, alkaline phosphatase (ALP) label was confined via a sandwich immunorecognition to convert 4-aminophenyl phosphate to the signal reporter 4-aminophenol (AP), which was then directed to interact with Ru(NH) as a redox mediator and tris (2-carboxyethyl) phosphine (TCEP) as reducing agent in the detection buffer. Upon illumination, the system was then operated upon the oxidation of Ru(NH) by the photogenerated holes on the BiS/BiVO photoelectrode, starting the chain reaction in which the Ru(NH) was regenerated by Ru(NH)-enabled oxidization of AP to p-quinoneimine, which was simultaneously recovered by TCEP.

A novel electrochemiluminescence resonance energy transfer system for simultaneous determination of two acute myocardial infarction markers using versatile gold nanorods as energy acceptors.

A novel electrochemiluminescence resonance energy transfer (ECL-RET) system using versatile gold nanorods as energy acceptors was introduced into the ECL biochemical analysis. A spatial- and potential-resolved platform coupled with the ECL-RET strategy was developed for simultaneous determination of two acute myocardial infarction markers.