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Abstract: A novel electrochemiluminescence (ECL) immunosensor based on the peroxydisulfate solution for detection of prostate-specific antigen (PSA) has been developed. In this work, gold nanoparticles (AuNPs) were electrodeposited on the glassy carbon electrode surface, which could increase the surface area to capture a large amount of primary antibodies as well as to improve the electronic transmission rate. The as-prepared bionanolabels, three-dimensional (3D) nanoflower-like MnO2 functionalized graphene (GN/MnO2), with novel hybrid architecture were initially fabricated via electrostatic interaction. Then, to provide an effective matrix for antibody immobilization with good stability and bioactivity, the novel materials were modified by AuNPs with the aid of poly (diallyldimethylammonium chloride) via a simple sonication-induced assembly method. In this immunosensor, MnO2 with the characteristics of well electrochemical behavior, low cost, and environmental-friendly, is used as a substitute for horseradish peroxidase to catalyze H2O2 to produce O2, and its 3D nanoflower-like structure is beneficial for the unparallel surface-to-volume ratio. Furthermore, a simple, low-cost and portable home-made potential transformer was utilized in this system to take the place of conventional electrochemical workstation. With a sandwich-type immunoassay format, the amount of functionalized GN/MnO2 labeled antibodies increased with the increment of antigens in the samples, which implied that the ECL signals enhanced with the increase of in situ generated O2 due to the enhancive catalysis of MnO2 to the H2O2. The immunosensor displayed excellent analytical performance for the detection of PSA in the range of 0.005–10ngmL−1 with a detection limit of 2.5pgmL−1 at 3σ. Moreover, the proposed method showed good precision, acceptable stability and reproducibility, and could be used for the detection of PSA in real samples. The proposed method provides a new promising platform of clinical immunoassay for other biomolecules. [Copyright &y& Elsevier]

Abstract: In this work, electrochemiluminescence (ECL) immunoassay was introduced into the recently proposed microfluidic paper-based analytical device (μPADs) based on directly screen-printed electrodes on paper for the very first time. The screen-printed paper-electrodes will be more important for further development of this paper-based ECL device in simple, low-cost and disposable application than commercialized ones. To further perform high-performance, high-throughput, simple and inexpensive ECL immunoassay on μPAD for point-of-care testing, a wax-patterned three-dimensional (3D) paper-based ECL device was demonstrated for the very first time. In this 3D paper-based ECL device, eight carbon working electrodes including their conductive pads were screen-printed on a piece of square paper and shared the same Ag/AgCl reference and carbon counter electrodes on another piece of square paper after stacking. Using typical tris-(bipyridine)-ruthenium (Ⅱ) - tri-n-propylamine ECL system, the application test of this 3D paper-based ECL device was performed through the diagnosis of four tumor markers in real clinical serum samples. With the aid of a facile device-holder and a section-switch assembled on the analyzer, eight working electrodes were sequentially placed into the circuit to trigger the ECL reaction in the sweeping range from 0.5 to 1.1 V at room temperature. In addition, this 3D paper-based ECL device can be easily integrated and combined with the recently emerging paper electronics to further develop simple, sensitive, low-cost, disposable and portable μPAD for point-of-care testing, public health and environmental monitoring in remote regions, developing or developed countries. [Copyright &y& Elsevier]

An ultrasensitive photoelectrochemical (PEC) immunosensor for the detection of carcinoembryonic antigen (CEA) was constructed using CdS@Cu 2 O co-sensitized porous ZnO nanosheets as photoactive materials and multiwalled carbon nanotubes (MWCNTs) as electrons sink. Porous ZnO was assembled on the MWCNTs modified indium tin oxides electrode to immobilize capture antibodies. With a sandwich immunoassay format, CEA and signal antibodies labeled CdS@Cu 2 O were introduced in sequence via specific immunoreaction, and the ultrahigh sensitivity of this immunoassay results from the following three aspects. First, the co-sensitization of Cu 2 O and CdS extends the absorption range of ZnO from ultraviolet region to visible light region, which can adequately utilize the light energy. Second, the effective matching of energy levels between the ZnO, CdS and Cu 2 O accelerates the separation and transfer of photogenerated electron-hole pairs and improves the PEC performance, significantly. Finally, the introduced MWCNTs evidently expedite the interfacial electron transfer from ZnO to electrode, further resulting in noticeably increased photocurrent. On the basis of multiple signal amplification strategy, a largely increased linear detection range from 1.0 pg mL −1 to 80 ng mL −1 with a low detection limit (0.4 pg mL −1 ) are obtained. Meanwhile, the prepared materials with attractive properties provide a promising platform for PEC detection. [ABSTRACT FROM AUTHOR]

In this work, we report a rapid, facile, portable, disposable and low-cost fluorescence and visual method for multiplexed monitoring of cancer cells using graphene oxide (GO)-based aptameric nanosensor in microfluidic paper-based analytical devices. This method has combined the exceptional quenching capability of GO and an aptamer with high specificity and affinity employed as the molecular recognition element. The quantum dots coated mesoporous silica nanoparticles labeled aptamers in a flexible single stranded state could be adsorbed on the surface of GO, and the fluorescence was quenched via Förster resonance energy transfer, with subsequent recovery of the fluorescence upon addition of target cells. Furthermore, the design of sensors for other cancer cells only requires change in the recognition element for the target cell and different colored quantum dots. More importantly, three different cancer cells can be simultaneously determined with a single excitation light. The sensitivity and selectivity of this method for GO-based sensing were extremely high. The color changes could be clearly monitored with the naked eye. And their linear range were from 180 to 8 × 10 7 , 210 to 7 × 10 7 , 200 to 7 × 10 7 cells mL −1 and detection limit were 6270 and 65 cells mL −1 for MCF-7, HL-60, and K562 cells, respectively. It could be applied in clinical sample analysis with a satisfactory result. Therefore, GO-based aptameric nanosensor is highly promising for potential applications in the sensitive monitoring of multiple cancer cells for biomedical research and medical diagnostics. [ABSTRACT FROM AUTHOR]

Herein, a photoelectrochemical (PEC) immunoassay is constructed for squamous cell carcinoma antigen (SCCA) detection using zinc oxide nanoflower-bismuth sulfide (Bi 2 S 3 ) composites as photoactive materials and reduced graphene oxide (rGO) as signal labels. Horseradish peroxidase is used to block sites against nonspecific binding, and then participated in luminol-based chemiluminescence (CL) system. The induced CL emission is acted as an inner light source to excite photoactive materials, simplifying the instrument. A novel signal amplification strategy is stem from rGO because of the rGO acts as an energy acceptor, while luminol serves as a donor to rGO, triggering the CL resonance energy transfer phenomenon between luminol and rGO. Thus, the efficient CL emission to photoactive materials decreases. Furthermore, the signal amplification caused by rGO labeled signal antibodies is related to photogenerated electron–hole pairs: perfect matching of energy levels between rGO and Bi 2 S 3 makes rGO a sink to capture photogenerated electrons from Bi 2 S 3 ; the increased steric hindrance hinders the electron donor to the surface of Bi 2 S 3 for reaction with the photogenerated holes. On the basis of the novel signal amplification strategy, the proposed immunosensor exhibits excellent analytical performance for PEC detection of SCCA, ranging from 0.8 pg mL −1 to 80 ng mL −1 with a low detection limit of 0.21 pg mL −1 . Meanwhile, the designed signal amplification strategy provides a general format for future development of PEC assays. [ABSTRACT FROM AUTHOR]

Background Human epididymis protein 4 (HE4) had been shown to be an ideal biomarker in ovarian cancer. However, there were fewer reports on its application in lung cancer. We explored the diagnostic value of serum HE4 as a biomarker in early lung cancer by comparing it with other biomarkers. Methods 162 individuals including 112 cases of lung cancer at early stage and 50 healthy people as controls were enrolled. The serum concentrations of biomarkers were determined with the Roche Elecsys assays. Results In comparison to the other biomarkers such as carcinoembryonic antigen (CEA), neuron-specific-enolase (NSE), serum cytokeratin 19 fragment (CYFRA 21-1) and progastrinreleasing peptide (proGRP), serum HE4 was one of the biomarkers with the highest sensitivity (43.8%) and specificity (95.0%) for early lung cancer diagnosis. In terms of histological results, serum HE4 was the best biomarker both in adenocarcinoma (AC) and squamous carcinoma (SC), and serum proGRP was the best in small cell lung cancer (SCLC). The combination of proGRP, NSE and HE4 could determine the histological type of lung cancer with a very high accuracy of 93.8%. Conclusions These findings suggested that serum HE4 was a better biomarker in early lung cancer than other frequently-used biomarkers. [ABSTRACT FROM AUTHOR]

Branched zinc oxide nanorods (BZR) arrays, an array with high charge carries collection efficiency and specific surface area, are grown on the reduced graphene oxide-paper working electrode for the first time to construct a paper-based electrochemical (EC) immunosensor. Typically, the BZR are fabricated via a simple hydrothermal process, which can provide abundant sites for antibodies loading. By combining the large surface area of porous zinc oxide (PZS) and good biocompatibility of gold nanoparticles (AuNPs), PZS–AuNPs (PZS@Au) nanocomposites are designed to label horseradish peroxide (HRP) and antigens. After a competitive reaction between antigens and PZS@Au nanocomposites labeled antigens, the signal labels are introduced into the immunosensor, in which, HRP participate in biocatalytic precipitation process. The produced precipitate reduces the electrode surface area and hinders the electron transfer. With the increase of concentration of antigens, the signal labels introduced into the sensor decrease, thus, a signal-on immunoassay for α-fetoprotein detection is constructed. The proposed paper-based EC immunosensor combines enzymatic biocatalytic precipitation reaction and competitive immunoassay mode for the first time, and possesses a wide linear range from 0.2 pg mL −1 to 500 ng mL −1 with a detection limit of 0.08 pg mL −1 . In addition, the proposed method is simple, sensitive and specific and can be a promising platform for other protein detection. [ABSTRACT FROM AUTHOR]

In our work, low potential and sensitive electrochemiluminescence (ECL) detection for CA153 on MCF-7 cell surface was firstly achieved based on a microfluidic paper-based analytical device. Au nanoflowers were grown in paper working electrode (PWE) to construct the ECL platform for primary antibodies immobilizing. After MCF-7 cells were captured in the modified PWE, and subsequently recognized with ECL signal substance labeled secondary antibodies, the sandwich-type cell sensor was fabricated. Graphene quantum dots (GQDs) loaded surface villous Au nanocages were synthesized as the ECL signal substance, and characterized by scanning electron microscope. The specific villous surface structure for Au nanocage permitted more GQDs being carried and electrons transporting, which largely benefited for the ECL performance. As the un-negligible impendence for MCF-7 cell would definitely influence the ECL signal, CA153 labeled HMEpic cell was used as the control cell to obtain more accurate determination result. This low-cost and fast strategy showed acceptable biocompatibility and stability, and will be promising for cellular immunochemistry. [ABSTRACT FROM AUTHOR]

In this work, multiplexed photoelectrochemical (PEC) immunoassays are introduced into an indium tin oxide (ITO) device. Firstly, the ITO device is fabricated using a simple acid etch treatment method. Secondly, AuPd alloy nanoparticles are electro-deposited on ITO working electrodes as electron sink to construct the immunosensor platform. After that, ZnO nanotubes (ZNTs) arrays are synthesized via chemical etching of ZnO nanorods that are grown on AuPd surface by electrochemical deposition method. Subsequently, CdS is electro-deposited on ZNTs arrays and used as photoactive material. Then, CuO nanoseeds are labeled with signal antibodies and firstly used as PEC signal amplification label. The introduction of CuO brings signal amplification because of the conduction band (CB) of both CuO and ZnO are lower than that of CdS, CuO will compete the photo-induced electrons in CB of CdS with ZnO, leading to the decrease of the photocurrent intensity. Using cancer antigen 125, prostate specific antigen and α-fetoprotein as model analytes, the proposed immunoassay exhibits excellent precision and sensitivity. Meanwhile, this work provides a promising, addressable and simple strategy for the multi-detection of tumor markers. [ABSTRACT FROM AUTHOR]

We reported here the synthesis of thin MoS 2 nanosheets, which showed a good catalysis of H 2 O 2 . The MoS 2 nanosheets were further synthetized into nano-composite MoS 2 -Au, and the MoS 2 -Au was found with a better catalysis property of H 2 O 2 and well electroconductibility. Furthermore, we composed Ag nanospheres (AgNPs), which have good electricity and large surface area. The prepared AgNPs and MoS 2 -Au were applied in a sandwich-type immunosensor for detecting carcinoembryonic antigen (CEA). In the immunosensor, MoS 2 -Au acted as the solid support for CEA primary antibody and AgNPs were employed as the supporter of glucose oxidase (GOx) and CEA secondary antibody. With the addition of glucose, the hydrogen peroxide was prepared and the MoS 2 -Au catalyzed hydrogen peroxide that the current peak was presented with the differential pulse voltammetry (DPV). The proposed immunosensor enabled CEA concentrations to be determined in the range of 1 pg mL −1 to 50 ng mL −1 , with a detection limit of 0.27 pg mL −1 . The immunosensor showed low detection limit, good specificity, high sensitivity and reproducibility. Satisfactory results were obtained for determination of CEA in human serum albumin samples. This work is to open new avenues in the application of AuNPs dotted MoS 2 composite interface for sensitive electrochemical immunoassay. Hence, the proposed electrochemical immunosensor could become a promising method for tumor marker detection. [ABSTRACT FROM AUTHOR]

Carbon coated magnetic composite nanoparticles (Fe 3 O 4 @C) were prepared and further fabricated into a new kind of the multifunctional core/shell nanoparticles (Fe 3 O 4 @C@CdTe) by a self-assembly of CdTe quantum dots. These nanoparticles exhibited good fluorescence (FL) property. In addition, zinc oxide (ZnO) nanowires (NWs) with high surface area were synthesized via solvothermal reaction under a hydrothermal condition. In a sandwich immune-device for the detection of carcinoembryonic antigen (CEA), the Fe 3 O 4 @C@CdTe nanoparticles were applied as the solid support for CEA-primary monoclonal antibody (CEA-McAb 1 ) and the ZnO NWs were applied as the label of CEA-secondary monoclonal antibody (CEA-McAb 2 ). The Fe 3 O 4 @C@CdTe-McAb 1 was collected at the bottom of the quartz cuvette using a magnet. The ZnO NWs bond with Fe 3 O 4 @C@CdTe after the immune reaction. The Zn 2+ ions are subsequently released from ZnO NWs by dissolution in acidic buffer solution and the enhanced FL intensity is measured. In this way, the proposed FL immune-device displayed excellent analytical performance for the detection of CEA in the range of 0.005–100 ng mL −1 with a low detection limit of 1.6 pg mL −1 , and the assay results of CEA in real serum samples were in a good agreement with the standard enzyme-linked immunosorbent assay (ELISA) tests. [ABSTRACT FROM AUTHOR]

An enzyme-free electrochemical immunoassay is introduced into microfluidic paper-based analytical devices for the first time using novel three dimensional flower-like Au nanoparticles modified paper working electrode (FLAuNPs-PWE) as sensor platform and gold (Au)-silver (Ag) bimetallic nanoparticles (Au-Ag BMNPs) as tracer. FLAuNPs with large surface area serve as an effective matrix for primary antibodies. Au-Ag BMNPs with good biological activity, such as mimicking natural peroxidases, are used for binding of signal antibodies (Ab 2 ). Then the Ab 2 labeled BMNPs is linked to the FLAuNPs-PWE via sandwich immunoreactions. Enhanced sensitivity is achieved by efficient catalysis of the Au-Ag BMNPs toward hydrogen peroxide. Under the optimized experimental conditions, the proposed paper-based electrochemical immunosensor exhibits excellent analytical performance for enzyme-free detection of carcinoembryonic antigen, ranging from 0.001-50 ng mL −1 with a low detection limit of 0.3 pg mL −1 . The immunosensor shows good precision, acceptable stability and reproducibility. The proposed method provides a new promising platform for the design of the highly sensitive detection method, showing great promise for clinical application. [ABSTRACT FROM AUTHOR]

Abstract: We reported here the synthesis of zinc ferrite (ZnFe2O4), which was further fabricated into gold nanoparticles (AuNPs) functionalized ZnFe2O4 (ZnFe2O4@Au) through a layer-by-layer (LBL) self-assembly method. The prepared ZnFe2O4@Au showed excellent catalytic performance to the reduction reaction procedure of hydrogen peroxide (H2O2), and the coated AuNPs provided the nanoparticles with good biocompatibility. In addition, the CdTe quantum dots dotted graphene (G–CdTe) was prepared and was found with good electrochemiluminescence (ECL) property. The prepared ZnFe2O4@Au and G–CdTe were applied in a simple sandwich-type ECL immunosensor for carcinoembryonic antigen (CEA). In the immunosensor, G–CdTe acted as the solid support for CEA primary antibody and ZnFe2O4@Au was employed as the supporter of CEA secondary antibody. The ZnFe2O4@Au could quench the ECL signal of the G–CdTe and the quenching ECL intensity could be obtained. The proposed immunosensor enabled CEA concentrations to be determined in the 0.01–50ngmL−1 concentration range, with a detection limit of 4pgmL−1. [Copyright &y& Elsevier]

A 3D electrochemiluminescence (ECL) origami immunodevice for highly sensitive detection of carcinoma antigen 125 (CA125) was designed based on in situ enzymatic reaction to generate H 2 O 2 as coreactant of peroxydisulfate solution with Pd@Au nanoparticles (NPs) as catalyst for signal amplification. The novel flower-like Ag@Au hybrids modified porous paper working electrode (Ag@Au-PWE) was prepared by a two-step growth approach and served as sensor platform for antibody attachment. Glucose oxidase (GOD) and signal antibody labeled Pd@Au NPs were linked to the Ag@Au-PWE surface via sandwich immunoreactions. Integrating the dual-signal amplification strategy, the proposed method exhibited high sensitivity and specificity for the detection of CA125 with a linear range of 0.1 mU·mL −1 to 100 U·mL −1 with a detection limit of 0.06 mU·mL −1 . Moreover, the facile immunodevice showed excellent stability and reproducibility in real human serum assay, indicating its wide range of potential applications in point-of-care testing. [ABSTRACT FROM AUTHOR]

Highlights: [•] A sandwich-type electrochemiluminescence (ECL) immunosensor for the sensitive detection of carcinoembryonic antigen was designed. [•] A novel nanocrystal luminophor of SnO2 quantum dot (QD) was applied as ECL signal reporter. [•] Nanoporous PtRu alloy were synthesized to load more SnO2 QDs due to their large area-to-volume ratio and excellent electron transfer rate. [•] Nanoporous silver was employed as a primary antibody carrier for our designed immunosensor based on a disposable microdevice. [Copyright &y& Elsevier]

Abstract: In this paper, the electrochemiluminescence (ECL) detection of a tumor marker by using gold–silver nanocomposite-functionalized graphene as a sensing platform, which increased the surface area to capture a large number of primary antibodies as well as improving the electronic transmission rate. The graphene quantum dots (GQDs) were high quantum yield and high biocompatible which obtained by one-pot simple synthetic strategy. With property of good conductivity and large surface area, porous PtPd nanochains can conjugate more GQDs and second antibody to improve the sensitivity of the immunoassay. As a proof-of-concept, carbohydrate antigen 199 was used as a model analyte. Under optimal conditions, the ECL immunosensors exhibited a wide detection range (0.002–70 U mL−1) and a low detection limit (0.96 mU mL−1). Such immunosensor showed good precision, acceptable stability and reproducibility. In addition, the proposed method provided a new promising platform of clinical immunoassay for other biomolecules. [Copyright &y& Elsevier]

Highlights: [•] A microfluidic origami multianalyte electrochemical immunodevice was fabricated. [•] Polyaniline-AuNPs modified paper working electrodes were used as sensor platform. [•] 3DGS were used as matrices to immobilize the redox probes and antibodies. [ABSTRACT FROM AUTHOR]

Abstract: A novel strategy was reported for the preparation of TiO2 nanobelts by the acid-assisted hydrothermal method. Complex nanopaper based on the TiO2 nanobelts and graphene was fabricated via a modified paper-making process. The as-prepared TiO2–graphene structure inherited the excellent electron transport of graphene and facilitated the spatial separation of photo-generated charge carrier, therefore resulting in the enhanced photocurrent, and making it a promising candidate for developing photoelectrochemical (PEC) biosensors. Thus, an advanced PEC biosensing platform for the detection of carcinoembryonic antigen was proposed at relatively low applied potential on screen-printed working paper-electrode using the as-prepared TiO2–graphene complex nanopaper. The complex nanopaper with good biocompatibility showed high PEC intensity and satisfactory stability, all of which held great promise for the fabrication of PEC biosensors with improved sensitivity. Furthermore, the TiO2–graphene complex nanopaper based PEC biosensor in this study was anticipated to provide the chance for the design of high-performance PEC biosensors for the detection of other enzymes and biomolecules. [Copyright &y& Elsevier]

Abstract: In this paper, a carbon coated magnetic nanoparticle (Fe3O4–C) was first synthesized via solvothermal reaction and carbonization of glucose under hydrothermal condition. The electrochemiluminescence (ECL) property of Fe3O4–C was studied, and exhibited a peak at 1.21V. In the goal to amplify the ECL intensity for sensitive detection, a novel coaxial carbon coated magnetic nanomaterial (MWNTs–Fe3O4–C) was synthesized. Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), powder X-ray diffraction (XRD) and powder X-ray photoelectron spectrometry (XPS) were applied as powerful tools to characterize and to demonstrate the named nanomaterial. MWNTs–Fe3O4–C showed better ECL property than Fe3O4–C. Furthermore, an ultrasensitive ECL immunosensor based on MWNTs–Fe3O4–C was developed for the determination of carcinoembryonic antigen (CEA). The prepared ECL immunosensor exhibited high sensitivity, good reproducibility, long-term stability, and acceptable precision on the detection of CEA in clinical human serum samples. [Copyright &y& Elsevier]

Abstract: A novel triple catalysis amplification strategy for simultaneous multiplexed electrochemical immunoassays based on cactus-like MnO2 functionalized nanoporous gold (NPG-MnO2) was designed. The NPG-MnO2 with enhanced catalytic activity, electrical conductivity and solubility was synthesized by an efficient, green and controllable approach. The obtained material was further characterized and used as matrices to immobilize the redox probes to produce a multiplexed electrochemical immunoassay. With the employment of the as prepared bioconjugates, triple catalysis amplification strategy was described duo to the enhanced catalytic effects of horseradish peroxidase (HRP) and two bio-mimetic enzymes (NPG and MnO2) through sandwich-type immunoassay protocol. [Copyright &y& Elsevier]

Abstract: A common rechargeable battery with an output voltage of 1.20V was used to develop a constant potential-triggered electroluminescence (ECL) protocol, and a low-cost toggle switch was self-assembled to convert the anodic or cathodic applied potential on working electrode by simply rotating. Based on the potential-resolution strategy, a facile ECL multiplexed immunoassay was constructed on single indium tin oxide working electrode for sequential detection of carcinoma antigen 153 and carcinoma antigen 199 (one working electrode for two analytes) by employing an anodic ECL label (Ru(bpy)3 2+-conjugated silica nanoparticles, +1.20V) and a cathodic one (carbon nanocrystals dotted silica nanoparticles, −1.20V). Under the optimal condition, the proposed multiplexed immunoassay displayed wide linear range with low detection limit, and the assay results for two tumor markers in human serum samples obtained by this system were in acceptable agreements with the reference values from commercially used method in Cancer Research Center of Shandong Tumor Hospital. The rechargeable battery-based ECL system and potential-resolution strategy equipped with a self-assembly toggle switch provided a low-cost, promising multiplexed immunoassay for point-of-care diagnosis. [Copyright &y& Elsevier]

Abstract: An easy approach was reported to synthesize graphene nanosheets attached to spiky MnO2 nanospheres (GS/MnO2) which showed good catalytic activity, electrical conductivity, solubility and processability. The synthetic method was efficient, green and controllable with graphene oxide reduced and MnO2 nanospheres formed in one step. The obtained material was further characterized and used as carriers for signal antibodies (Ab2) to produce an electrochemiluminescent immunosensor based on prepared nanoporous gold–graphene nanosheets platform. With a sandwich-type immunoassay format, the amount of GS/MnO2 labeled Ab2 went up with the increased concentration of antigens in the sample. Such immunosensor exhibited high sensitivity in the detection of carcinoembryonic antigen in serum samples. [Copyright &y& Elsevier]

Abstract: In this paper, a novel, low-cost electrochemiluminescence (ECL) immunosensor using core–shell Fe3O4–Au magnetic nanoparticles (AuMNPs) as the carriers of the primary antibody of carbohydrate antigen 125 (CA125) was designed. Graphene sheet (GS) with property of good conductivity and large surface area was a captivating candidate to amplify ECL signal. We successively synthesized functionalized GS by loading large amounts of quantum dots (QDs) onto the poly (diallyldimethyl-ammonium chloride) (PDDA) coated graphene sheet (P-GS@QDs) via self-assembly electrostatic reactions, which were used to label secondary antibodies. The ECL immunosensors coupled with a microfluidic strategy exhibited a wide detection range (0.005–50UmL−1) and a low detection limit (1.2mUmL−1) with the help of an external magnetic field to gather immunosensors. The method was evaluated with clinical serum sample, receiving good correlation with results from commercially available analytical procedure. [Copyright &y& Elsevier]

Abstract: In this paper, a 3D microfluidic origami device combined with electrochemiluminescence (ECL) immunosensor was introduced for sensitive point-of-care testing of carcinoma antigen 125 in clinical serum samples for the first time. This microfluidic origami device was fabricated by directly screen-printing carbon working, counter electrodes and Ag/AgCl reference electrode including their conductive pads on wax-patterned pure cellulose paper, and was activated by folding to form a 3D electrochemical cell. To construct a sensitivity-enhanced sandwich-type ECL immunosensor, gold nanoparticles (AuNPs) was synthesized to modify the working electrode to provide a good pathway of electron transfer and enhance the immobilized amount of capture antibody (McAb1), and luminol functionalized gold nanoparticles (Lu-AuNPs) was synthesized to label signal antibody (McAb2). With the aid of a facile device-holder, cyclic voltammetry was applied on microfluidic origami ECL immunodevice to trigger ECL. Under optimal conditions, this microfluidic origami ECL immunodevice provided a good linear response range from 0.01 to 100UmL−1 with a detection limit of 0.0074UmL−1. The proposed ECL immunodevice presented high sensitivity and stability, and could be applied in point-of-care testing of other tumor markers for remote regions and developing countries. [Copyright &y& Elsevier]

Abstract: In this paper, a sandwich-type electrochemiluminescent (ECL) immunosensor was fabricated for the detection of carcinoma embryonic antigen (CEA) on a portable indium tin oxide (ITO) device. Gold-coated magnetic iron nanoparticles (Fe@Au MNPs) were synthesized as solid support to immobilize CEA-primary monoclonal antibody (CEA-McAb1). CdTe quantum dots (QDs) was used to label CEA-secondary antibodies (CEA-McAb2). The transparent ITO device was fabricated using a simple, low-cost, fast acid etch technique, which integrated counter electrode, reference electrode and working electrode in a piece of ITO glass. Under cyclic voltammetry condition, the ECL of CdTe QDs was enhanced by the energy transfer reaction from the excited Fe@Au MNPs surface plasmon resonance to CdTe QDs, and the possible mechanism was investigated. The proposed immunosensor provided a wide linear response range (0.001–50ngmL−1) with a low detection limit (0.38pgmL−1). The assay results of CEA in clinical serum samples were in a good agreement with the standard enzyme-linked immunosorbent assay (ELISA) tests. The proposed enhanced ECL immunosensor may provide potential application for detection of other tumor markers. [Copyright &y& Elsevier]