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The van der Waals heterojunction is able to combine the advantages of different materials and has potential to be used in biosensing researches. In this study, we developed a novel van der Waals heterojunction by combining MXene and MoS 2 nanosheets for the electrochemiluminescence (ECL) sensing applications. This van der Waals heterojunction material not only possessed the superior conductivity of MXene, but also regulated the electron transport. Additionally, the incorporation of MoS 2 nanosheets into the MXene interlayers significantly enhances the material stability. Meanwhile, nitrogen-rich quantum dots (N dots) were synthesized as ECL tags with an impressive nitrogen content of up to 75 %. By integrating the ECL response of N dots within the van der Waals heterojunction, we established a highly efficient sensing system for miRNA-373, which overexpressed in triple negative breast cancer tissues. The van der Waals heterojunction-based biosensor can enhance the ECL signal of N dots effectively to detect miRNA-373 from 1 fM to 1 μM. Consequently, the developed sensing system holds promise for the early detection of metastasis of the triple-negative breast cancer, paving the way for the effective clinical interventions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In this work, the dual-ligand lanthanide metal-organic framework (MOF)-based electrochemiluminescence (ECL) sensor was constructed for the detection of miRNA-128 in glioblastoma (GBM) diagnosis. The luminescent Eu-MOF (EuBBN) was synthesized with terephthalic acid (BDC) and 2-amino terephthalic acid (BDC-NH 2 ) as dual-ligand. Due to the antenna effect, EuBBN with conjugated-π structure exhibited strong luminescent signal and high quantum efficiency, which can be employed as ECL nanoprobe. Furthermore, the novel plasmonic CuS@Au heterostructure array has been prepared. The localized surface plasmon resonance coupling effect of the CuS@Au heterostructure array can amplify the ECL signal of EuBBN significantly. The EuBBN/CuS@Au heterostructure array-based sensing system has been prepared for the detection of miRNA-128 with a wide linear range from 1 fM to 1 nM and a detection limit of 0.24 fM. Finally, miRNA-128 in the clinic GBM tissue sample has been analysis for the distinguish of tumor grade successfully. The results demonstrated that the dual-ligand MOF/CuS@Au heterostructure array-based ECL sensor can provide important support for the development of GBM diagnosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Aggregation-induced emission (AIE) has been widely used in research on electrochemiluminescence (ECL) due to its excellent luminescence intensity. In this work, copper superparticles (Cu SPs) were used to construct ECL biosensor to detect the microRNA-103a (miRNA-103a) in triple-negative breast cancer (TNBC) tumor tissues. Firstly, GSH-capped copper clusters were used as precursors to prepare Cu SPs by the AIE effect. Compared with clusters, Cu SPs possessed higher luminescence performance and energy stability, making them an ideal choice for ECL nanoprobe. The film of PVDF-HFP/CeVO 4 NPs was constructed and modified with CPBA and GSH as the sensing interface (PCCG). The PCCG film displayed good conductivity and hydrophilicity, and desirable mechanical stability. Moreover, the PCCG film can induce high carrier mobility rates and dissociate large amounts of the co-reactant K 2 S 2 O 8 to enhance the ECL intensity of Cu SPs. As a result, the prepared ECL sensor with the catalyzed hairpin assembly (CHA) strategy was employed to quantify miRNA-103a in the range of 100 fM to 100 nM. The biosensor provided a novel analytical approach for the clinical diagnosis of TNBC., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In this work, miRNA-10b in the glioblastoma (GBM) tumor tissues has been detected by a novel electrochemiluminescence (ECL) biosensor. Firstly, a new kind of bright luminescent Zn 2 GeO 4 :Mn NPs were prepared as ECL nanoprobe, which possessed high fluorescence quantum yield and ECL quantum efficiency. Secondly, Ti 3 C 2 MXene hydrogel (MXG) have been developed as the sensing interface. The MXG retained the inherent biocompatibility and mechanical features of hydrogel. Furthermore, the uniform distribution of metallic Ti 3 C 2 MXene in the hydrogel microstructure provided the good conductivity and multiple binding sites for biomolecules. MXene also can promote the separation of the electrons and holes to accelerate the electron-transfer rate and improve ECL efficiency. Due to these synergistic effects, the screen printed electrode was successfully modified with MXG as sensing platform to enhance the ECL intensity of Zn 2 GeO 4 :Mn NP, which greatly improved the detection efficiency and facilitated the high-throughput analysis. Finally, the toehold mediated strand displacement (TMSD) strategy was employed with then biosensor to detect miRNA-10b with the range of 10 fM to 1 nM. The limit of detection was 5 fM. This ECL biosensor has been used to analyze miRNA-10b expression in GBM tumor tissues, which possessed the great potential value for clinical diagnosis., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Qiang MA reports financial support was provided by National Natural Science Foundation of China.., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Tumor-derived extracellular vesicles detection has emerged as an important clinical liquid biopsy approach for cancer diagnosis. In this work, we developed a novel hybrid plasmonic nanocavity consisting of hexagonal Au nanoplates nanoarray, SnS 2 /Au nanosheet layer and biomimetic lipid bilayer. Firstly, the hybrid plasmonic nanocavity combined the optical confinement for the ECL regulation and the biological recognition for the detection of extracellular vesicles. Secondly, MXene-derived Ti 2 N QDs have been prepared as ECL nanoprobe to label extracellular vesicles. Moreover, biomimetic lipid bilayer with specific aptamer was used to identify extracellular vesicles and integrate Ti 2 N QDs into the nanocavity with membrane fusion strategy. Due to the significant electromagnetic field enhancement at the cavity region, the hybrid plasmonic nanocavity provided strong field confinement to concentrate and redistribute the ECL emission of QDs with a 9.3-fold enhancement. The hybrid plasmonic nanocavity-based ECL sensing system improved the spatial controllability of EVs analysis and the accurate resolution of specific protein. It achieved the sensitive detection of extracellular vesicles in ascites and successfully distinguished the peritoneal metastasis of gastric cancer., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Herein, a novel electrochemiluminescence (ECL) and differential pulse voltammetry (DPV) dual-mode-based molecularly imprinted (MIP) sensor had been established for the detection of enrofloxacin (ENR) in eggs. Firstly, bismuth sulfide quantum dots (Bi 2 S 3 QDs) as ECL luminophore were synthesized. Furthermore, a MIP film with ionic liquid (ILs), Bi 2 S 3 QDs, and ENR was prepared via the electrochemical polymerization procedure on the electrode. As ENR was identified and captured by the imprinted cavities, the electron transfer pathway was blocked on the electrochemical interface, resulting in the decrease of both DPV signals and ECL signals. As a novel synchronous dual-mode sensing strategy, a pulsed voltage was applied to produce both the DPV signal and ECL signal simultaneously. The ECL and DPV response showed the good linear relationships with the concentration of ENR with the ranges of 0.5 Nm-25 μM and 5 nM-25 μΜ and the detection limits of 0.13 nM and 1.59 nM, respectively., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Gastric cancer (GC) was one of the most common cancers with high mortality. The detection of GC peritoneal metastasis had important significance. In this work, we have developed the novel electrochemiluminescence (ECL) biosensor to detect microRNA in GC extracellular vesicle (EV). Firstly, in situ growth of Cu nanocluster (Cu NC) on the metal-organic frameworks (MOFs) nanosheet was achieved successfully. Due to the confinement effect, Cu NCs in the porous structure of Zn MOF possessed the high quantum yield and good stability. Meanwhile, Zn MOF provided good electrochemical activity for the ECL reaction. Furthermore, the nanosized MOFs did not only act as sensing platform to load Cu NCs and link biomolecules, but also reduce steric hindrance effect for biomolecular recognition. Additionally, Au NPs/MXene and phospholipid layer were prepared and modified on the electrode, which can regulate electron transfer and improve the target recognition efficiency. The Cu NCs/Zn MOF nanosheet-based ECL sensor was employed to detect miRNA-421 from 1 fM to 1 nM with a detection limit of 0.5 fM. Finally, extracellular vesicles form clinic GC patient ascites were extracted and analyzed. The results showed that the constructed biosensor can be used for the GC peritoneal metastasis diagnosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Metal-organic frameworks (MOFs) porous material have obtained more and more attention during the past decade. Among various MOFs materials, luminescent MOFs with specific chemical characteristics and excellent optical properties have been regarded as promising candidates in the research of cancer biomarkers detection and bioimaging. Therefore, the latest advances and the principal biosensing and imaging strategies based on the luminescent MOFs were discussed in this review. The effective synthesis methods of luminescent MOFs were emphasized firstly. Subsequently, the luminescent principle of MOFs has been summarized. Furthermore, the luminescent MOF-based sensing mechanisms have been highlighted to provide insights into the design of biosensors. The designability of LMOFs was suitable for different needs of biorecognition, detection, and imaging. Typical examples of luminescent MOF in the various cancer biomarkers detection and bioimaging were emphatically introduced. Finally, the future outlooks and challenges of luminescent MOF-based biosensing systems were proposed for clinical cancer diagnosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Mass probes attached with aptamers and mass tags offer excellent specificity and sensitivity for multiplexed detection, wherein the dissociation of mass tags from the mass probes is as important as their labeling. Herein, aggregation-induced emission luminogen (AIEgen)-tagged mass probes (AIEMPs) were established to analyze estrogens, which integrated aptasensor with an explosive mass-tag signal amplification strategy via a simple ultrasound-assisted emulsification of nanoliposomes. The AIEMPs were assembled by the hybridization of aptamer-modified Fe 3 O 4 nanoparticles (Fe NPs@Apt) and nanoliposomes loaded with massive AIEgen mass tags and partially complementary DNA strands (AIE NLs@cDNA). The aptamer was preferentially and specifically bound to estrogen, resulting in the detachment of AIE NLs from AIEMPs. Subsequently, the AIEMPs were deposited with electrospray solvents for explosive release of mass tags. Using nanoelectrospray ionization mass spectrometry (nanoESI-MS), the AIEMP-based aptasensor achieved ultrasensitive analysis of estrogens with limits of detection of 0.168-0.543 pg/mL and accuracies in the range of 87.9-114.0%. Compared to direct nanoESI-MS detection, the AIEMP-based aptasensor provides a signal amplification of four orders of magnitude. Furthermore, the utilization of different AIEMPs enables multiplexed detection of three estrogens with a miniature mass spectrometer, showing promising potential for on-site detection. This work expands the diversity of mass-tagging strategy and provides a versatile mass probe-based aptasensor platform for routine MS detection of trace analytes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Plasmonic nanocavity possessing highly light field confinement and electromagnetic field enhancement can concentrate and enhance the luminescence signal. The plasmonic nanocavity has the great potential value in biosensing research and improve analytical sensitivity. In this work, we constructed a plasmonic nanocavity between circular Au nanoplate-film and spherical Au nanoparticle with tetrahedral DNA nanostructures. The nanocavity structure can regulate the local density of optical states and provide the field restriction to enhance the spontaneous ECL radiation of PEDOT-S dots. Additionally, Au nanoparticle acted as nanoantenna which localized and modulated ECL to directional emission. Because the plasmonic nanocavity effectively collected and redistributed ECL signal, the emission was enhanced by 5.9 times with polarized characteristics. The proposed plasmonic nanocavity-based ECL sensor was further used to detect exosomal miRNA-223-3p in ascites. The detection results indicated the novel sensing strategy can assist early diagnosis of peritoneal metastasis of gastric cancer., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Although luminescence metal organic framework (MOFs) has displayed the significant advantages, the limitations in the electrochemical performance (e.g. rapid charge recombination rates and inadequate charge transport) limited the sensing application of MOFs. Herein, a novel Cu-MOFs/BiVO 4 nanorod-based electrogenerated chemiluminescence (ECL) sensor has been developed. Firstly, Cu-MOFs with strong luminescence were synthesized via the three-layer approach as ECL emitter. Furthermore, BiVO 4 nanorods was modified on the electrode as the actuator to improve the electrochemical activity of Cu-MOFs in the ECL process. As an n-type semiconductor, BiVO 4 formed a complementary structure with p-type semiconductor Cu-MOF. Therefore, electrons in the conduction band of BiVO 4 transferred to that of Cu-MOF. As a result, more electrons reacted with coreactant on the surface of Cu-MOF, which effectively enhanced the ECL performance of 2D Cu-MOFs nanosheets. As a result, the quantitation of KRAS gene was realized in the linear range of 0.1 pM-1 nM with a detection limit of 0.02 fM. Moreover, the detection of KRAS gene in actual colorectal cancer samples was also carried out with good recovery, which offered a broad application possibility for ECL research and clinical analysis., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Qiang MA reports financial support was provided by National Natural Science Foundation of China. Qiang MA reports a relationship with Key Research and Development Projects of Jilin Provincial Science and Technology Development Plan that includes: funding grants., (Copyright © 2023 Elsevier B.V. All rights reserved.)

In this work, a novel electrochemiluminescence (ECL) sensor has been developed to detect the miRNA-522 in the tumor tissues of triple-negative breast cancer (TNBC) patients. Au NPs/Zn MOF heterostructure was obtained by in situ growth and used as novel luminescence probe. Firstly, zinc-metal organic framework nanosheets (Zn MOF NSs) were synthesized with Zn 2+ as the central metal ion and 2-aminoterephthalic acid (NH 2 -BDC) as the ligand. 2D MOF nanosheets with ultra-thin layered structure and relatively large specific surface areas can enhance the catalytic activity in the ECL generation. Furthermore, the electron transfer capacity and the electrochemical active surface area of MOF were greatly improved by the growth of Au NPs. Therefore, Au NPs/Zn MOF heterostructure showed the significant electrochemical activity in the sensing process. In addition, the magnetic Fe 3 O 4 @SiO 2 @Au microspheres were used as capture units in the magnetic separation step. The magnetic spheres with hairpin aptamer H1 can capture target gene. Then the captured miRNA-522 triggered the target catalyzed hairpin assembly (CHA) sensing process and linked Au NPs/Zn MOF heterostructure. The concentration of miRNA-522 can be quantified by the ECL signal enhancement of the Au NPs/Zn MOF heterostructure. Due to the high catalytic activity of Au NPs/Zn MOF heterostructure and their unique structural and electrochemical properties, the prepared ECL sensor achieved high-sensitive detection of miRNA-522 in the range of 1 fM to 0.1 nM with the detection limit of 0.3 fM. This strategy can provide a potential alternative for miRNA detection in medical research and clinical diagnosis of triple negative breast cancer., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2023 Elsevier B.V. All rights reserved.)

MiRNAs played critical roles in triple negative breast cancer (TNBC) as potential biomarkers. Herein, an efficient signal "off-on" mode-biosensor based on electrochemiluminescence resonance energy transfer (ECL-RET) was successfully constructed for the miRNA-150-5p determination in TNBC. The ECL-RET regulated-sensing platform consisted of NiMn-LDHs nanoflowers, the artificially assembled phospholipid bilayers and hairpin DNA-labeled Eu-doped MoS 2 QDs. Firstly, Eu-doped MoS 2 QDs with high quantum efficiency were prepared as the ECL-RET donors. And NiMn-layer double hydroxides (LDHs) nanoflowers with wide UV-vis absorption spectra as the ECL-RET acceptors. Secondly, due to the hairpin DNA structure, the closed distance between ECL-RET donor-acceptor pair can quench the luminescence signal of Eu-doped MoS 2 QDs. When miRNA-150-5p was captured, the hairpin DNA structure changed to a rodlike configuration and enlarged the distance between Eu-doped MoS 2 QDs and NiMn-LDHs. As a result, the recovery of ECL signal can be observed as a signal "turn off-on" mode. Furthermore, the hydrophilicity of the lipid bilayer can reduce the nonspecific adsorption and improve the flexibility of the hairpin DNA efficiently. Therefore, based on the ECL-RET regulation strategy, the biosensor was employed to detect miRNA-150-5p from 10 fM to 1 nM with a detection limit of 1.5 fM. The constructed biosensor can effectively differentiate TNBC patient tumor and healthy breast fibroadenoma. The ECL-RET regulation strategy provided a new biosensing pathway for ultrasensitive detection of biomolecules and promoted the development of diagnosis and treatment of TNBC., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

In this work, a novel plasmonic heterodimer with controllable hot spot was designed and applied to regulate surface plasmon coupling electrochemiluminescence (SPC-ECL) polarization sensing system. The heterodimer nanostructure consisted of individual Au-Ag core-shell nanocubes (Au@Ag NC) and Au nanospheres (Au NS), which were precisely assembled by thiol-DNA and biotin-streptavidin. The asymmetric nanostructure can significantly modulate the ECL intensity and emission polarization angle based on the synergy of the surface plasmon coupling (SPC) effect and the lightning rod effect with extraordinary field enhancement in the hot spot region. As a result, the isotropic ECL signal of zinc-doped nitrogen dots (Zn-N dots) was regulated in the directional emission. Furthermore, the SPC-ECL biosensor was successfully applied to detect miRNA-182 in triple-negative breast cancer (TNBC) tissues. The research on the established relationship between ECL polarization analysis and plasmonic heterodimers can provide a new pathway for the development of ECL sensing platforms.

Exosomes play an important role in the proliferation, adhesion and migration of cancer cells. In this study, we have developed a novel electrochemiluminescence (ECL) sensor based on MoS 2 QDs-MXene heterostructure and Au NPs@biomimetic lipid layer to detect exosomal miRNA. MoS 2 QDs-MXene heterostructure had been prepared as the luminescence probe. Ti 3 C 2 T x MXene nanosheets possessed the large specific surface area, excellent flexibility and superior conductivity. MoS 2 QDs on the MXene nanosheets worked as the radiation center to generate strong ECL signal. Meanwhile, Au NPs with biomimetic lipid layer have been modified on the electrode, which retained the lipid dynamics and excellent antifouling property. When miRNA-135b was recognized on the Au NPs@biomimetic lipid layer, MoS 2 QDs-MXene heterostructure was linked on the electrode and further extended the outer Helmholtz plane. As a result, the self-luminous Faraday cage-mode sensing system has been used to detect miRNA-135b from 30 fM to 20 nM with a detection limit of 10 fM. Furthermore, gastric cancer exosomal miRNA in the ascites of clinical patients has been detected successfully. The sensing system can be served as a versatile platform with huge application potential in the field of exosome detection., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

In this study, a novel surface plasmon-coupled electrochemiluminescence (SPC-ECL) biosensor was developed based on bismuth nano-nest and Ti 3 CN quantum dots (Ti 3 CN QDs). First, MXene derivative QDs (Ti 3 CN QDs) with excellent luminescence performance were prepared as the ECL luminescent. The N doping in Ti 3 CN QDs can effectively improve the luminescence performance and catalytic activity. Therefore, the luminescence performance of QDs has been effectively improved. Furthermore, the bismuth nano-nest structure with a strong localized surface plasmon resonance effect has been designed as the sensing interface via the electrochemical deposition method. It was worth noticed that the morphology of bismuth nanomaterials can be controlled effectively on the electrode surface by the step potential method. Due to the abundant surface plasmon hot spots generated between the bismuth nano-nests, the isotropic ECL signal of Ti 3 CN QDs can be not only significantly enhanced by 5.8 times but also converted into polarized emission. Finally, the bismuth nano-nest/Ti 3 CN QD-based SPC-ECL sensor was used to quantify miRNA-421 in the range of 1 fM to 10 nM. The biosensor has been successfully used for miRNA in ascites samples from gastric cancer patients, which indicated that the SPC-ECL sensor developed in this study has great potential for clinical analysis.

Cu nanoclusters (NCs) have attracted a lot of attention due to the excellent properties. However, the low luminescence and poor stability limited the Cu NC-based sensing research. In this work, Cu NCs were in situ synthesized on CeO 2 nanorods. On the one hand, the aggregated induced electrochemiluminescence (AIECL) of Cu NCs has been observed on the CeO 2 nanorods. On the other hand, the substrate of CeO 2 nanorods acted as catalysis, which reduced the excitation potential and further enhanced the ECL signal of Cu NCs. It was noticed that CeO 2 nanorods also greatly improved the stability of Cu NCs. The resulted high ECL signals of Cu NCs can be kept constant for several days. Furthermore, MXene nanosheets/Au NPs has been employed as electrode modification materials to construct the sensing platform to detect miRNA-585-3p in triple negative breast cancer tissues. Au NPs@MXene nanosheets not only enlarged the specific interface area of the electrodes and the number of reaction sites, but also modulated electron transfer to amplify the ECL signal of Cu NCs. The biosensor had a low detection limit (0.9 fM) and a wide linear range (1 fM to 1 μM) for the detection of miRNA-585-3p in the clinic tissues., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

In this work, a novel ECL biosensor has been developed based on bimetallic MXene derivative QDs (Mo 2 TiC 2 QDs) and SnS 2 nanosheets/lipid bilayer to detect the gastric cancer marker miRNA-27a-3p. On the one hand, the inter-band excitation of Mo 2 TiC 2 QDs can inject the additional carriers, which were less suppressed by boundary effects and made a significant contribution to the luminescence process. Semiconductor Mo 2 TiC 2 further inhibited the formation of internal electric field and potential oxidation. Therefore, Mo 2 TiC 2 QDs processed superior luminous intensity and better stability. On the other hand, SnS 2 nanosheets coated with phospholipid bilayer were designed as sensing interface. SnS 2 nanosheets not only enhanced the luminous intensity of Mo 2 TiC 2 QDs by virtue of their large surface area and low dielectric constant, but also improved the stability of lipid bilayer. Due to the excellent properties and synergy work of Mo 2 TiC 2 QDs and the lipid bilayer-modified SnS 2 nanosheets, the sensing system displayed high sensitivity and good reproducibility in the analysis application. As a result, the biosensor displayed good linear correlation between the ECL intensity and the concentration of miRNA-27a-3p over a wide range from 1 fM to 10 nM with the detection limit as low as 1 fM. The sensing system including the joint contribution of Mo 2 TiC 2 QDs, SnS 2 nanosheets and lipid bilayers had great potential for clinical applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Exosomes of cancer cells play an important role in the proliferation, adhesion, and migration of tumors. Especially, exosomes in the tumor microenvironment can reflect the proliferation of tumors directly, thus serving as ideal referenced markers of the possibility and grade of malignancy in neoplasms. However, the sensitive and accurate detection of exosomes remains challenging. In this work, a novel three-dimensional (3D) plasmonic nanostructure was constructed for exosomal miRNA detection. It combined the advantages of Au nanostar monolayer and Ag nanowire monolayer to provide multiple hot spots. Moreover, Au nanostar monolayer changed the isotropic electrochemiluminescence (ECL) into polarized emission. The Ag nanowire monolayer worked as waveguides for the light direction. As a result, the polarized resolution and intensity of ECL signal were improved. The polarized ECL emission was significantly increased by 47.1 times. This high-resolution polarized ECL sensor was used for detecting exosomal miRNA-146b-5p in the thyroid tumor microenvironment. This sensor showed the linear range from 1 fM to 1 nM with a detection limit of 0.3 fM. The satisfactory results indicated the developed 3D plasmonic nanostructure-based ECL sensor had great potential in biosensing and clinical diagnosis.

Exosomes are a class of the nanosized extracellular vesicles, which have emerged as representative liquid biopsy biomarkers. To date, the electrochemical nanosensors are of great significance in the exosome detection with the advantages of easy operation, high accuracy and reliable repeatability. Especially, the growing field of nano interface has provided the electrochemical sensing platforms for the accurate exosomes analysis. The incorporation of multiple nanomaterials can take advantages and synergistic properties of functional units. So, based on the integration of with nanomaterial-based signal transduction and specific biorecognition, the nano-sensing interface provides excellent electrochemical features owing to rapid mass transport and excellent conductivity. The nano-sensing interface with a wide variety of morphologies and structure also provides the large active surface area for the immobilization of bio-capturing agents. Furthermore, through the design of nanostructured electrode array, the efficiency of transducer can be greatly improved. It should be noticed that the elaboration of a proper sensor requires the profound knowledge of the nano-sensing interface. Therefore, this article presents a review of the recent advance in exosomes detection based on the electrochemical nano-sensing interface, including electrochemical analysis principles, exosome sensing mechanisms, nano-interface construction strategies, as well as the typical diagnosis application. In particular, the article is focused on the exploration of the various electrochemical sensing performance of nano-interface in the exosome detection. We have also prospected the future trend and challenge of the electrochemical nano-sensing interface for exosomes analysis in clinical cancer diagnosis., (Copyright © 2022 Elsevier B.V. All rights reserved.)

In this work, a highly efficient electrochemiluminescence (ECL) biosensor was developed based on the nanosponge-hydrogel system for uric acid (UA) detection. First, the nanosponge consisted of polylactic acid glycolic acid (PLGA) nanoparticles immobilized with MoS 2 quantum dots (QDs) and urate oxidase (UAO). The marked loading capability of PLGA nanoparticles enables loading many biomolecules and QDs for the specific recognition of UA. Urate oxidase on the nanosponge can catalyze UA to generate H 2 O 2 in situ, which further triggers the ECL signal for the MoS 2 QDs. Furthermore, the biocompatible acrylamide-based hydrogel not only effectively retained the functionalities of the chimeric nanosponge-hydrogel, but also provided structural integrity and engineering flexibility on the electrode for ECL sensing applications. In addition, there were many ester groups and amide bonds in the nanosponge-hydrogel structure. Therefore, many electron can be excited in the ECL process due to the large number of lone electron pairs on oxygen and nitrogen atoms. This resulted in a seven-fold ECL enhancement of the MoS 2 QDs. Finally, the nanosponge-hydrogel structure-based ECL biosensor was successfully used in real clinical serum assays. This showed a good analytical performance for UA detection (100-500 μmol/L) with a limit of detection of 20 μmol/L., (© 2022 John Wiley & Sons Ltd.)

In this work, a polarization-resolved electrochemiluminescence (ECL) sensor for microRNA-155 (miRNA-155) detection has been constructed based on the surface plasmon coupling effect. In the sensing system, nitrogen dots (N dots) were employed as ECL emitters. As a surface-enhanced structure, a gold nanorod vertical array was constructed on the electrode surface by the volatilization-induced self-assembly. The coupling of the adjacent gold nanorods in the array can generate significant local electromagnetic fields. Due to the anisotropy of gold nanorods and the hot spot effect of the vertical array, the ECL signal of N dots was greatly improved at a specific polarization angle. In addition, the catalytic hairpin self-assembly strategy was used to amplify the nucleic acid analyte signal. As a result, the polarization-resolved ECL sensor can detect miRNA-155 sensitively, which is related to triple-negative breast cancer.

In this work, a novel electrochemiluminescence (ECL) sensor has been developed to detect miRNA-210 in the serum of triple negative breast cancer (TNBC) patients. The luminous MoS 2 nanosheets were synthesized via the solvothermal method and served as ECL emitters for the first time. As a result, the ECL properties of as-prepared MoS 2 nanosheets were significantly improved. Furthermore, the biomimetic magnetic vesicles were used as capture platform in the ECL sensing strategy. Due to the highly efficient fluidity and magnetic property, the biomimetic vesicles with hairpin aptamers can capture target gene in the serum. After magnetic separation, the captured miRNA-210 can trigger the target-catalyzed hairpin assembly (CHA) sensing process on the magnetic electrode and hybridize MoS 2 nanosheets labeled probe DNA. The concentration of miRNA-210 can be quantified by the ECL enhancement of the MoS 2 nanosheets. This approach has achieved the sensitive detection for miRNA-210 in a range from 1 fM to 100 pM with the detection limit of 0.3 fM. The luminous MoS 2 nanosheets-based ECL sensing system with the biomimetic vesicles would provide a new pathway to explore 2D nanomaterials for developing a wide range of bioanalytical applications., (Copyright © 2021. Published by Elsevier B.V.)

MXene material has been gradually studied in recent years due to its fascinating characteristics. This work developed a novel MXene-derived quantum dots (MQDs) @gold nanobones (Au NBs) heterostructure as the electrochemiluminescence (ECL) sensor. First, MXene and MQDs were synthesized via the green preparation process, which avoided the harm of hydrofluoric acid to humans and the environment. There was a strong ECL signal enhancement in the MQD@Au NBs heterostructure. On the one hand, Au NBs with surface plasmon resonance (SPR) effect acted as an "electronic regulator" that can transfer electrons to itself to control over-injection of electrons into the conduction band of MQDs. The luminous signal of MQDs can be efficiently generated and significantly amplified in the ECL sensing process. On the other hand, the work function of MQDs with excellent conductivity was relatively close to that of Au NBs in the heterostructure. So, ECL quenching caused by short-distance electron transfer between luminophore and Au nanomaterial has been effectively suppressed. The MQD@Au NBs heterostructure-based ECL sensing system was applied to determine miRNA-26a in the serum of patients with triple-negative breast cancer. It not only provides ideas for the green synthesis of MXene but also provides a guide for the application of MQD@Au NBs heterostructure in the field of ECL sensing.

This work focused on the construction of a nanomaterial-patterned structure for high-resolved ECL signal modulation. Due to the surface coupling effect, the different shapes and distribution states of surface plasmonic nanomaterials not only affect the luminescence intensity enhancement but also decide the electrochemiluminescence (ECL) polarization characteristics. Herein, tin disulfide quantum dots were synthesized via a solvothermal method as ECL emitters. Compared with other nanostructures, Au nanotriangle (Au NT) displayed both the localized surface plasmon resonance electromagnetic enhancement effect and the tip amplification effect, which had significant hot spot regions at three sharp tips. Therefore, self-assembled Au NT-based patterned structures with high density and uniform hot spots were constructed as ideal surface plasmonic materials. More importantly, the distribution states of the hot spots affect the polarization characteristics of ECL, resulting in directional ECL emission at different angles. As a result, a polarization-resolved ECL biosensor was designed to detect miRNA 221. Moreover, this polarization-resolved biosensor achieved good quantitative detection in the linear range of 1 fM to 1 nM and showed satisfactory results in the analysis of the triple-negative breast cancer patients' serum.

The accurate and sensitive detection of glucose from secretory clinical samples, such as tears and saliva, remains a great challenge. In this research, a novel ultrasensitive glucose detection method consisting of a glucose oxidase (GOx), pistol-like DNAzyme (PLDz), and CRISPR-Cas12a system is proposed. First, the oxidation of glucose catalyzed by GOx leads to the production of H 2 O 2 ; the self-cleavage activity of PLDz is activated after recognition of the produced H 2 O 2 . The two procedures triggered by COx and PLDz play an important role in accurately identifying glucose and converting glucose signals to nucleic acids. The obtained PLDz fragments can be recognized by the Cas12 enzyme and thus activate the trans -cleavage activity of the Cas12a enzyme. Finally, the surrounding reporter probes are cut by the Cas12a enzyme to produce fluorescence signals. In summary, an ultra-sensitive and specific fluorescence method has been developed for glucose detection from secretory clinical samples, which could potentially contribute to the noninvasive diagnosis of diabetes mellitus.

In this research, a novel Ag 3 PO 4 NPs@MoS 2 nanosheet-based electrochemiluminescence (ECL) sensing system was developed to provide an effective method for tumor gene detection. At first, fluorine, sulfur-doped BN quantum dot (F, S-BN QD) were prepared as ECL emitter. Sulfur dopant can provide more reactive sites in the ECL reaction. Fluorine atoms in the QD structure further improved the stability of the crystal. Furthermore, Ag 3 PO 4 NP@MoS 2 nanosheets were fabricated via a hydrothermal route as ECL reaction catalyst. On the one hand, Ag 3 PO 4 NP@MoS 2 nanosheets promoted the generation of more oxidant of coreactant in the F, S-BN QD/H 2 O 2 coreactant ECL pathway. On the other hand, the excellent conductivity of Ag 3 PO 4 NP@MoS 2 nanosheets facilitated the electron transfer and effectively reduce the damage of F, S-BN QD by excessive hot electrons. Finally, the proposed biosensor was designed to accurately quantify K-ras tumor gene from 10 fM to 100 pM with a limit of detection (LOD) of 0.2 fM. The sensing system was used to detect K-ras gene in human colorectal cancer tumor and tumor-adjacent tissues samples with satisfactory results. The amplified ECL sensing strategy with Ag 3 PO 4 NPs@MoS 2 nanosheet has significant potential value in the clinical detection., (Copyright © 2021 Elsevier B.V. All rights reserved.)

A smart electrochemiluminescent (ECL) sensor has been designed in this work. The sensing system consisted of Ag NPs-Ti 3 AlC 2 nanosheets (Ag-TACS) as the self-luminous Faraday cage and biomimetic magnetic vesicles as the functional substrate. By engineering the structure and properties of Ti 3 AlC 2 nanosheets to induce the Faraday-cage effect, the outer Helmholtz plane (OHP) was extended to contribute to ECL enhancement. Compared with the Faraday cage that further incorporated luminous materials, the self-luminous Faraday cage in the "direct label" model kept all the luminous materials on the OHP. Meanwhile, biomimetic magneticvesicles with highly efficient fluidity were used to improve the sensing efficiency and obtain a perfect Faraday-cage structure to enhance the ECL signals. The highest ECL enhancement (ca. 25 times) has been achieved by the synergistic effect of the Faraday cage and biomimetic magnetic vesicles. This sensing system was used to detect the wild-type K-ras gene in the colorectal tumor tissue. It provides not only an important guide for the novel ECL sensing concept but also a smart modulation system of the electromagnetic field.

A novel multiplex electrochemiluminescence (ECL) polarization assay was developed to detect breast cancer-related genes BRCA1 and BRCA2 simultaneously based on the polarization characteristics of surface plasmon-coupled electrochemiluminescence (SPC-ECL). In this work, boron nitride quantum dots (BN QDs) were used as ECL emitters, and gold nanoparticles (Au NPs) and gold-coated silver nanoparticles (Ag@Au NPs) were employed as surface plasmon materials. The surface plasmon coupling resonance of different metal NPs not only enhanced the ECL intensity but also converted the isotropic emission into directional emission. This study revealed the relation between the structure of metal nanomaterials and SPC-ECL, and a high polarization-resolved sensing system was designed to detect multitarget DNA from 100 aM to 1 nM simultaneously. Polarization-based multiple ECL analysis has broad prospects in related cancer diagnosis and treatment evaluation.

Herein, we constructed a DNA-mediated Au-Au dimer-based surface plasmon coupling electrochemiluminescence (SPC-ECL) sensor. In the SPC-ECL sensing system, graphite phase carbon nitride quantum dots (GCN QDs) worked as an ECL emitter. A DNA rigid chain structure was employed to connect two Au NPs in an equilateral triangle configuration to form the Au-Au dimers. Due to the hot spot effect, the designed Au-Au dimers had a strong electromagnetic field intensity, which can greatly enhance the ECL signal of GCN QDs than a single Au nanoparticle. The gap distance of dimers can be effectively regulated by the DNA length, which resulted in different electromagnetic field intensities. Therefore, the different SPC-ECL amplification effects on the GCN QD signal by Au-Au dimers have been revealed. The maximum ECL signal of GCN QDs can be enhanced fourfold based on the Au-Au dimers with a gap distance of 2 nm. Furthermore, the biosensor showed good analytical performance for the detection of breast cancer susceptibility gene 1 (BRCA1 genes) (1 fM-1 nM) with a detection limit of 0.83 fM. This work provided an effective and precise SPC-ECL sensing mode for the diagnosis and prognosis of breast cancer.

Herein, Fe 3 O 4 NP@ZIF-8/MoS 2 QD-based electrochemiluminescence (ECL) biosensor with nanosurface energy transfer strategy was successfully developed for point-of-care determination of ATP. With the porous structure and poor electron transfer ability, Fe 3 O 4 NP@ZIF-8 complex was first used as an excellent catalyst in ECL. The complex catalyzed the coreactant for more free radicals and hindered the quenching effect of Fe 3 O 4 nanoparticles (NPs) on quantum dots (QDs). In ECL-nanosurface energy transfer (NSET) system, through the specific binding of complementary DNA linked to MoS 2 QDs (QDs-cDNA) and aptamer linked to Au NPs, interaction between the point dipole of MoS 2 QDs and the collective dipoles of Au NPs quenched ECL signal. When ATP was captured by aptamer, the ECL-NSET system was taken apart, which resulted in the recovery of ECL signal. Moreover, changes of the ECL imaging can be captured by a smartphone, which enabled point-of-care determination of ATP from 0.05 nmol L -1 to 200 nmol L -1 with LOD of 0.015 nmol L -1 . With superior specificity and stability, the sensing system showed significant potential about the application of catalysts coated with ZIF and NSET in point-of-care ECL determination., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In recent years, electrochemiluminescence (ECL) nanosensing systems have undergone rapid development and made significant progress in ultrasensitive analysis and cell imaging. Because of the unique advantages of high selectivity, ultra-sensitivity, and good reproducibility, ECL nanosensors can open new paths for cancer diagnosis. With the development of ECL nanosensors, high-throughput analysis, visual detection and spatially resolved ECL imaging of single cells are being realized. The innovations of ECL nanosensors consist of electrochemical excitation, coreactant catalysis, light radiation and luminescence signal amplification, which involve several fields such as nanotechnology, catalysis, optics, and electrochemistry. The developments of ECL instruments also relate to imaging technology. Herein, we review the construction modes, sensing strategies and cancer diagnosis applications of ECL nanosenors. Firstly, the nano-components of the ECL sensing system are discussed. The construction and signal amplification methods of the nanosensing system are emphasized. Secondly, the high-efficiency cancer identification strategies are presented, including protein tumor marker detection, nucleic acid assay, cancer cell identification and exosome detection. The recent advances in representative examples of ECL nanosenors in cancer diagnosis are highlighted, including high-throughput ECL analysis, in situ assay, visual ECL detection, single-cell imaging diagnosis, and so on. Finally, the challenges are featured based on the recent development of the ECL nanosensing system in the clinical diagnosis. The ECL nanosensors provide effective and reliable analytical methods and open new paths for cancer diagnosis. It is noteworthy that the prospects of the ECL nanosensing system in clinical diagnosis are instructive to the developments of other nanosensor research.

The first polarized-electrochemiluminescence (ECL) biosensor is reported in this work. Surface plasmon coupling ECL (SPC-ECL) strategy is developed for the amplified polarization light of fluorine-doped BN quantum dot (F-BN QD) emitters. The generation of polarized-ECL is attributed to the characteristic of polarization-angle-dependent SPC effect. A polarized sandwich-type biosensor based on F-BN QDs and Au nanoparticles (Au NPs) is established to detect the K-ras gene. The polarized-ECL sensor is more sensitive with lower detection limit than the isotropic ECL sensing system. The sensor can quantify the K-ras gene from 0.1 fM to 10 nM, with the detection limit as 0.03 fM. This work not only explores polarized SPC-ECL, but also offers a new analytical method for clinical diagnosis. The generation of polarized-ECL and the amplification strategy of the SPC effect opens a new path for ECL-resolved analyses.

Excessive secretion of PTH leads to disturbance of calcium and phosphorus metabolism in the body, which promotes bone, kidney, digestive system and nervous system diseases. Due to the short half-life of PTH, it becomes a difficult issue for PTH detection in the clinical diagnosis field. We explored a competitive immunofluorescent sensing mode based on FRET of two-color CdTe QDs for ratiometric PTH 1-84 antigen detection. The FRET effect and ratiometric fluorescence between the two-color CdTe QDs motivated accurate quantification of PTH 1-84 antigen concentration from 0.01 ng mL -1 to 0.08 ng mL -1 with a limit of detection of 3 pg mL -1 . More importantly, under UV irradiation, samples with different concentrations of PTH 1-84 antigen achieved fluorescence visualization, which provides huge possibility for the practical application of PTH 1-84 antigen point-of-care detection.

Nonmetallic plasmonic MoS 2 nanosheets were synthesized by hydrothermal top-down method. MoS 2 nanosheets had shown strong surface plasmon coupling (SPC) light absorption in the visible and near-infrared region. Herein, the nonmetallic plasmonic MoS 2 nanosheets were employed to enhance the electrochemiluminescence (ECL) signal of sulfur doped boron nitrogen QDs (S-BN QDs) in this work. It is important to regulate the distance between ECL luminophore and plasmonic nanoparticles. On one hand, too closed distance can cause energy or electron transfer, which could quench the ECL intensity of nano-luminophore. On the other hand, plasmonic nanostructure cannot significantly affect the luminescence in the far distance. Therefore, we discussed the distance-dependent plasmon-enhanced ECL in detail with different length DNA chains. Furthermore, we constructed a hybridization chain reaction (HCR) amplification ECL sensing mode with the SPC-ECL strategy. The proposed DNA sensor can quantify hepatitis C virus (HCV) gene from 0.5 pmoL/L to 1 nmoL/L with a limit of detection (LOD) of 0.17 pmoL/L., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Although graphite phase carbon nitride quantum dots (GCN QDs) showed some advantages in the electrochemiluminescence (ECL) analytical research, the low ECL efficiency limited the potential sensing application. Herein, we synthesized sulfur-doped graphite phase carbon nitride quantum dots (S-GCN QDs) to fabricate a sandwich sensor based on amplified surface plasmon coupling ECL (SPC-ECL) mode. Sulfur doping can change the surface states of QDs effectively and produced new element vacancy. As a result, the ECL efficiency of S-GCN QDs was 2.5× over GCN QDs. Furthermore, compared with the big gap between the ECL peak of GCN QDs (620 nm) and the absorption peak of Au NPs, the doped sulfur elements in S-GCN QDs generated new ECL emission peaks at 555 nm, which was closed to the absorption peak of Au NPs at 530 nm. Due to the wavelength-dependent surface plasmon coupling effect, the ECL peak of S-GCN QDs at 555 nm had greater amplitude of enhancement in the sensing system. The proposed biosensor can quantify the K-RAS gene from 50 fM to 1 nM with a limit of detection (LOD) of 16 fM. We were the first to provide insight into the role of wavelength-dependent surface plasmon coupling in enhancing the sensitivity of ECL biosensor.

In this work, polydopamine electrochemiluminescence (ECL)-organic nanoparticles (EONs) based immunosensing strategy was designed for parathyroid hormone (PTH) detection. Dopamine is oxidized and polymerized to form polydopamine organic nanoparticle via self-polymerization process. Unlike the low photoluminescent efficiency and unsatisfactory fluorescence characters of the fluorescent organic nanoparticles (FONs), the polydopamine EONs do not only show unique physicochemical properties and excellent biocompatibility, but also provide ideal electrochemical properties and bright ECL signals, which can be employed as high-quality ECL luminophores. The ECL-related properties and performance of the EONs are further discussed in this paper. The sensing method has a linear response in the range of 0.05-8 ng/mL with a detection limit of 17 pg/mL. The applicability of this method is evaluated through the determination of PTH in human plasma samples with satisfactory results. To our best knowledge, this was the first time about the exploration of polydopamine organic nanoparticles as ECL luminophores in the biosensing application., (Copyright © 2019 Elsevier B.V. All rights reserved.)

This work describes a surface plasmon coupling electrochemiluminescence (SPC-ECL) method for the determination of the Shiga toxin-producing Escherichia coli (STEC) gene. Firstly, gold nanoparticles (Au NPs) were encapsulated into a solid silica core (AuNP@SiO 2 ). Secondly, graphite phase carbon nitride quantum dots (g-C 3 N 4 QDs) were embedded in the mesoporous silica shell (mSiO 2 ) to form nanospheres of type AuNP@C 3 N 4 QD@mSiO 2 . It is found that the surface plasmon coupling effect of the Au NPs in the solid silica core strongly enhances the ECL of the g-C 3 N 4 /K 2 S 2 O 8 system. The mSiO 2 carry much of the ECL luminophore (g-C 3 N 4 QDs), and the co-reactant can readily pass the mesopores to react with QDs to give an ECL reaction. Because of these two features, the ECL is 3.8 times stronger compared to ECL sensing using g-C 3 N 4 QDs only. Finally, AuNP@C 3 N 4 QD@mSiO 2 was linked to the probe DNA to construct a competitive DNA sensor. When no target DNA is added, most of the capture DNA on the electrode is complementary to the probe DNA of AuNP@C 3 N 4 QD@mSiO 2 -probe DNA. At this time, the ECL signal is the strongest. When the target DNA is added, some of the capture DNA is paired with it and the remaining capture DNA is paired with the probe DNA. Consequently, less luminophore reaches the electrode and the signal is weaker. The method works in the 0.1 pM to 1 nM concentration range and has a 9 fM detection limit. It was successfully applied to the ultrasensitive determination of the STEC gene in human serum. Graphical abstract Schematic illustration for the "egg-yolk puff" structured ECL sensor based on Au NPs, g-C 3 N 4 QDs, and mesoporous silica shell.

Because boron nitride quantum dots (BN QDs) have a wider gap (5.0-6.0 eV) than other QDs, the edge configurations, chemical functionalities, and heteroatom dopants can decrease and regulate the band gap of BN QDs, thereby ameliorating the QDs' properties. Now, the precise control and regulation of BN QDs are still at an early stage and is a challenging task. Therefore, we used thiourea and l-cysteine as different sulfur precursors to regulate the BN QDs' optoelectronic properties in this study. It is interesting that two kinds of S-regulated BN QDs present significantly different electrochemiluminescence (ECL) properties and electro-optical activity. Furthermore, a ratiometric and enzyme-free ECL sensing mode is constructed with the amplified surface plasmon coupled-ECL (SPC-ECL) strategy. The proposed DNA sensor can quantify the BRAF gene from 1 pmol/L to 1.5 nmol/L with a limit of detection (LOD) of 0.3 pmol/L. The change of BN QDs' ECL signal was easily observed with a smartphone camera. This work for the first time provides insight into the role of sulfur regulation in enhancing ECL efficiency and the electro-optical activity of BN QDs.

In this work, a novel surface plasmon resonance (SPR) enhanced electrochemiluminescence (ECL) biosensing model was first designed based on Au NPs@polydopamine (PDA)@CuInZnS QDs nanocomposite. Au NPs were coated with the PDA layer via the electrostatic force. CuInZnS QDs were bound on the surface of Au NPs@PDA nanocomposite. CuInZnS QDs worked as ECL luminophore in the sensing application. PDA shell not only controlled the separation length between Au NPs and QDs to induce SPR enhanced ECL response, but also limited the potential charge transfer and ECL quenching effect. As a result, the nanocomposite ECL intensity was twice that of QDs with K 2 S 2 O 8 . The tumor suppressor p53 gene was detected in the amplified ECL sensing system. The sensing method has a linear response in the range of 0.1 nmol/L to 15 nmol/L with a detection limit of 0.03 nmol/L. The DNA biosensor based on the nanocomposite showed excellent sensitivity, selectivity, reproducibility and stability and was applied in spiked human serum samples with satisfactory results., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A novel kind of water-dispersible molecularly imprinted nanohybrids containing multi-walled carbon nanotubes (MWCNTs) was prepared via the combination of co-assembly and photocrosslinking, and employed to construct an electrochemical sensor. A photo-crosslinkable amphiphilic copolymer (Poly(AA-co-VMc-co-EHA), PDHES) was firstly synthesized, which could co-assemble with MWCNTs in the presence of template molecule (paracetamol, PCM) in aqueous solution, generating photo-crosslinkable molecularly imprinted nanohybrids (MIP-MWCNTs). A robust MIP-MWCNTs film was formed on the electrode surface via the deposition of MIP-MWCNTs nanohybrids and the subsequent photo-crosslinking. After extracting paracetamol molecules, an electrochemical MIP-MWCNTs sensor was successfully developed. The as-prepared MIP-MWCNTs sensor showed a significantly wide linear detection range (0.1-2500 μM) and low detection limit (0.02 μM), owing to the large surface area of MIP-MWCNTs nanohybrids and superior electrical conductivity of MWCNTs, which affords a direct channel for the electron transfer from the recognition cavities to the electrode surface and thus enhances the response signal. In addition, good selectivity toward paracetamol (the imprinting factor α is 7.5) and ultrafast response time (less than 180 s) of MIP-MWCNTs sensor have also been demonstrated. The MIP-MWCNTs sensor also exhibited satisfactory repeatability and stability, which has been successfully utilized to measure paracetamol in urine samples with good results, demonstrating a promising feature for applications in medical diagnostics., (Copyright © 2018 Elsevier B.V. All rights reserved.)

In this paper, a facilely prepared electrochemiluminescence (ECL) biosensor was developed for Escherichia coli O157:H7 quantitative detection based on a polydopamine (PDA) surface imprinted polymer (SIP) and nitrogen-doped graphene quantum dots (N-GQDs). N-GQDs with a high quantum yield of 43.2% were synthesized. The uniform PDA SIP film for E. coli O157:H7 was established successfully with a facile route. The dopamine and target bacteria were electropolymerized directly on the electrode. After removal of the E. coli O157:H7 template, the established PDA SIP can selectively recognize E. coli O157:H7. Accordingly, E. coli O157:H7 polyclonal antibody (pAb) was labeled with N-GQDs. The bioconjugation of SIP-E. coli O157:H7/pAb-N-GQDs can generate intensive ECL irradiation with K 2 S 2 O 8 . As a result, E. coli O157:H7 was detected with the ECL sensing system. Under optimal conditions, the linear relationships between the ECL intensity and E. coli O157:H7 concentration were obtained from 10 1 colony-forming units (CFU) mL -1 to 10 7 CFU mL -1 with a limit of detection of 8 CFU mL -1 . The biosensor based on this SIP film was applied in water sample detection successfully. The N-GQD-based ECL analytical method for E. coli O157:H7 was reported for the first time. The sensing system had high selectivity to the target analyte, provided new opportunities for use, and increased the rate of disease diagnosis and treatment and the prevention of pathogens.

In this work, a novel multiplex electrochemiluminescence (ECL) DNA sensor has been developed for determination of hepatitis B virus (HBV) and hepatitis C virus (HCV) based on multicolor CdTe quantum dots (CdTe QDs) and Au nanoparticles (Au NPs). The electrochemically synthesized graphene nanosheets (GNs) were selected as conducting bridge to anchor CdTe QDs551-capture DNA(HBV) and CdTe QDs607-capture DNA(HCV) on the glassy carbon electrode (GCE). Then, different concentrations of target DNA(HBV) and target DNA(HCV) were introduced to hybrid with complementary CdTe QDs-capture DNA. Au NPs-probe DNA(HBV) and Au NPs-probe DNA(HCV) were modified to the above composite film via hybrid with the unreacted complementary CdTe QDs-capture DNA. Au NPs could quench the electrochemiluminescence (ECL) intensity of CdTe QDs due to the inner filter effect. Therefore, the determination of target DNA(HBV) and target DNA(HCV) could be achieved by monitoring the ECL DNA sensor based on Au NPs-probe DNA/target DNA/CdTe QDs-capture DNA/GNs/GCE composite film. Under the optimum conditions, the ECL intensity of CdTe QDs551 and CdTe QDs607 and the concentration of target DNA(HBV) and target DNA(HCV) have good linear relationship in the range of 0.0005-0.5 nmol L(-1) and 0.001-1.0 nmol L(-1) respectively, and the limit of detection were 0.082 pmol L(-1) and 0.34 pmol L(-1) respectively (S/N = 3). The DNA sensor showed good sensitivity, selectivity, reproducibility and acceptable stability. The proposed DNA sensor has been employed for the determination of target DNA(HBV) and target DNA(HCV) in human serum samples with satisfactory results., (Copyright © 2016 Elsevier B.V. All rights reserved.)

In this work, we developed an ultrasensitive "turn on-off" fluorescence nanosensor for lysozyme (Lyz) detection. The novel nanosensor was constructed with the carboxymethyl chitosan modified CdTe quantum dots (CMCS-QDs). Firstly, the CMCS-QDs were fabricated via the electrostatic interaction between amino groups in CMCS polymeric chains and carboxyl groups on the surface of QDs. In the fluorescence "turn-on" step, the strong binding ability between Zn(2+) and CMCS on the surface of QDs can enhance the photoluminescence intensity (PL) of QDs. In the following fluorescence "turn-off" step, the N-acetyl-glucosamine (NAG) section along the CMCS chains was hydrolyzed by Lyz. As a result, Zn(2+) was released from the surface of QDs, and the Lyz-QDs complexes were formed to quench the QDs PL. Under the optimal conditions, there was a good linear relationship between the PL of QDs and the Lyz concentration (0.1-1.2 ng/mL) with the detection limit of 0.031 ng/mL. The developed method was ultrasensitive, highly selective and fast. It has been successfully employed in the detection of Lyz in the serum with satisfactory results., (Copyright © 2014 Elsevier B.V. All rights reserved.)

QD-Au NP@silica mesoporous microspheres have been fabricated as a novel enzyme-mimic nanosensor. CdTe quantum dots (QDs) were loaded into the core, and Au nanoparticles (NPs) were encapsulated in the outer mesoporous shell. QDs and Au NPs were separated in the different space of the nanosensor, which prevent the potential energy or electron transfer process between QDs and Au NPs. As biomimetic catalyst, Au NPs in the mesoporous silica shell can catalytically oxidize glucose as glucose oxidase (GOx)-mimicking. The resultant hydrogen peroxide can quench the photoluminescence (PL) signal of QDs in the microsphere core. Therefore the nanosensor based on the decrease of the PL intensity of QDs was established for the glucose detection. The linear range for glucose was in the range of 5-200 μM with a detection limit (3σ) of 1.32 μM., (Copyright © 2014 Elsevier B.V. All rights reserved.)

In this work, a novel fluorescence "turn off-on" nanosensor for the determination of heparin and heparinase based on CuInS2 quantum dots (QDs) was established. CuInS2 QDs (modified by l-cysteine) featuring amino groups were directly prepared in aqueous solution via a hydrothermal synthesis method. The amino groups on the surface of CuInS2 QDs can interact with sulfate and carboxylate groups in heparin via electrostatic interactions and hydrogen bonding, which led the fluorescence of CuInS2 QDs to "turn-off". However, the heparin could be hydrolyzed into small fragments in the presence of heparinase, which resulted in the fluorescence of CuInS2 QDs being recovered. Therefore, the addition of heparinase to the heparin/CuInS2 QDs system activated the fluorescence of CuInS2 QDs to "turn-on" state. Thus, the determination of heparin and heparinase could be achieved by monitoring the fluorescence "turn off-on". Under the optimum conditions, there was a good linear relationship between I/I0 (I and I0 were the fluorescence intensity of CuInS2 QDs in the presence and absence of heparin, respectively) and heparin concentration in the range of 0.05-15 μmol L(-1) with the detection limit of 12.46 nmol L(-1). The linear detection for heparinase was in the range of 0.2-5 μg mL(-1) with the detection limit of 0.07 μg mL(-1). The proposed nanosensor was employed for the detection of heparin in fetal bovine serum samples with satisfactory results., (© 2013 The Authors. Published by Elsevier B.V. All rights reserved.)

A novel ZnO nanorods/ferrocenyl-alkanethiol (FcC11SH) bilayer structure was prepared and applied for the fabrication of glucose enzymatic biosensor. ZnO nanorod matrix was synthesized by low temperature aqueous method and provided a favorable environment for the immobilization of glucose oxidase (GOx). A monolayer of FcC11SH molecular was self-assembled on the surface of gold electrode and introduced a shuttling way for electronic communication between GOx and electrode. The morphology and structure of prepared ZnO nanorods were characterized by employing scanning electron microscopy (SEM), and X-ray powder diffraction (XRD). Electrochemcial measurements of the sensor revealed a high and reproducible sensitivity of 27.8 μA cm(-2) mM(-1), and a linear range from 0.05 to 1.0mM with a detection limit of 20 μM. A relatively low value of Michaelis-Menten constant about 2.95 mM indicates the enhanced affinity of GOx to glucose. To the best of our knowledge, this is the first time to fabricate the glucose biosensor by using ZnO and FcC11SH bilayer structure., (© 2013 Elsevier B.V. All rights reserved.)

A sensitive and stable label-free electrochemical impedance immunosensor for the detection of Salmonella typhimurium was developed by immobilising anti-Salmonella antibodies onto the gold nanoparticles and poly(amidoamine)-multiwalled carbon nanotubes-chitosan nanocomposite film modified glassy carbon electrode (AuNPs/PAMAM-MWCNT-Chi/GCE). Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to verify the stepwise assembly of the immunosensor. Co-addition of MWCNT, PAMAM and AuNPs greatly enhanced the sensitivity of the immunosensor. The immobilisation of antibodies and the binding of Salmonella cells to the modified electrode increased the electron-transfer resistance (Ret), which was directly measured with EIS using [Fe(CN)6](3-/4-) as a redox probe. A linear relationship of Ret and Salmonella concentration was obtained in the Salmonella concentration range of 1.0×10(3) to 1.0×10(7) CFU mL(-1) with a detection limit of 5.0×10(2) CFU mL(-1). Additionally, the proposed method was successfully applied to determine S. typhimurium content in milk samples with satisfactory results., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

In this article, a kind of simple, sensitive, and rapid quantum dots (QDs)-based multiplex DNA sensor is developed for the simultaneous detection of BRAF and BRCA DNA based on the "nano-on-micro" technique. In our strategy, capture DNA(BRCA) and DNA(BRAF) are simultaneously immobilized on the surface of amino-modified silica microbeads. After blocking with bovine serum albumin (BSA), different concentrations of target DNA(BRCA) and DNA(BRAF) are introduced to hybrid with complementary capture DNA(BRCA) and DNA(BRAF). After hybridization, QDs546-labeled probe DNA(BRAF) and QDs657-labeled probe DNA(BRCA) were added into the above solution so that the unreacted capture DNA(BRCA) and DNA(BRAF) could be detected by QDs657-labeled probe DNA(BRCA) and QDs546-labeled probe DNA(BRAF) simultaneously. We demonstrate that the proposed method is effective for detecting BRAF and BRCA DNA with high sensitivity. The sensor has great potential to expand its application to the early diagnosis of cancers such as breast cancer, ovarian cancer, and papillary thyroid carcinoma., (Copyright © 2013 Elsevier Inc. All rights reserved.)