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Flap endonuclease 1 (FEN1) is a structure-specific nuclease, which catalyzes the removal of 5' overhanging DNA flap from a specific DNA structure. FEN1 has been considered as an important biomarker for cancer diagnosis since it is over-expressed in various types of human tumor cells and closely related to cancer development. Nanoprobes gradually become basic tools for analyzing biomarkers variations in vivo. Here, we utilized aminoated mesoporous silica nanoparticles (NH 2 -MSNs) with a rich porous structure as the fluorescence nanoprobes to entrap the rhodamine 6G (Rh6G) molecules. Then gold nanoparticles linked specific single-stranded DNA (AuNPs-ssDNA) as a molecular gate was used to coat the NH 2 -MSNs surface. The fluorescence signal was weak when the fluorescence molecules were blocked by the AuNPs-ssDNA. In the presence of FEN1, it recognized and cleaved the specific ssDNA to release the Rh6G from NH 2 -MSNs, which resulted in recovered fluorescence signals. Thus, the sensitive detection of FEN1 activity was realized by controlled-release of Rh6G. The fluorescence signal showed a good linear relationship with the logarithm of FEN1 activity ranging from 0.05 to 1.75 U with a detection limit of 0.03 U. Moreover, confocal imaging demonstrated that the proposed biosensor could distinguish tumor cells from normal cells. Therefore, this technique contributes to clinical diagnostic and therapeutic monitoring., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The immunosuppressive tumor microenvironment (TME) poses tremendous challenges for efficient immunotherapy. Smart nanomedicine is designed to modulate immunosuppressive TMEs based on the combination of dual-enhanced photodynamic therapy (PDT) triggered immunogenic cell death (ICD) and relieved hypoxic microenvironment. Copper(II) metalated metal-organic framework nanosheets (Cu-TCPP(Al)) are the foundation of the nanomedicine, and platinum nanoparticles (Pt NPs) and folate are subsequently introduced onto the Cu-TCPP(Al) surface (Cu-TCPP(Al)-Pt-FA). Upon targeted cellular uptake, intracellular GSH concentration is decreased because of the specific adsorption between GSH and Cu II ; meanwhile, Pt NPs possess catalase-like activity, which can continuously depose intracellular H 2 O 2 to O 2 to alleviate the hypoxic TME. The two factors synergistically improve the ROS concentration for dual-enhanced PDT. The highly toxic ROS can correspondingly cause amplified oxidative stress and then trigger the ICD. The ICD process stimulates antigen-presenting cells and activates the systemic antitumor immune response. Furthermore, the relieved hypoxic TME increases the infiltration of cytotoxic T lymphocytes (CTLs) at the tumor site, which can promote the transformation of the immunosuppressive M2 macrophage to immunoactive M1 phenotype. The easily prepared yet versatile nanomedicine possesses an excellent antitumor effect with the cooperation of dual-enhanced PDT and immunotherapy.

Consuming glucose by glucose oxidase (GOx) has attracted great interest in cancer starvation therapy, but the therapeutic effect is severely limited by the tumor hypoxia environment. Herein, to overcome such limitation, cancer cell membranes disguised biomimetic nanoreactors were elaborately established for synergetic cancer starvation therapy and cascade amplificated hypoxia activated chemotherapy. Via a metallothionein-like self-assembly and infiltration approach, GOx and hypoxia activated prodrug banoxantrone (AQ4N) were efficiently loaded into metal-organic framework ZIF-8 nanocarriers to yield nanoreactor AQ4N/GOx@ZIF-8. Subsequently, the biomimetic nanoreactor (AQ4N/GOx@ZIF-8@CM) was obtained by camouflaging the nanoreactor with cancer cell membrane, which endowed the biomimetic nanoreactor homotypic targeting, immune escape and prolonged blood circulation features. Once targeted accumulating into tumor sites, the acid environment triggered the decomposition of ZIF-8, then encapsulated GOx and AQ4N were released. GOx would rapidly exhaust endogenous glucose and O 2 to shut off the energy supply of tumor cells for starvation treatment. Furthermore, the aggravated tumor intracellular hypoxia environment would activate the cytotoxicity of AQ4N for chemotherapy. In vitro and in vivo results demonstrated that the designed biomimetic nanoreactor exhibited negligible systemic toxicity, besides, the combination of starvation therapy and cascade amplified hypoxia activated chemotherapy significantly inhibited the tumor growth and improved the therapeutic efficacy., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Multidrug resistance is a major cause of failure in the clinical cancer therapy, in which the overexpression of P-glycoprotein (P-gp) plays a crucial role. Herein, we fabricate a theranostic nanoprobe with the function of simultaneous detection and inhibition of P-gp to diagnose and combat multidrug-resistant cancer in vitro and in vivo. For constructing the nanoprobe, elacridar modified quantum dots (QDs-Ela), acting as a gatekeeper, are grafted onto the doxorubicin (DOX) loaded, folic acid (FA) decorated mesoporous silica nanoparticles (MSNs). Upon targeted uptake by multidrug-resistant cancer cells, Bel-7402/ADR are used as a model, the acidic environment results in QDs-Ela removal from the nanoprobe, and subsequent DOX release. The removed QDs-Ela could specifically combine with P-gp in the cancer cell membrane and inhibit their active sites, which prevents the efflux of intracellular DOX and increases the retention of DOX. Another way, the fluorescence intensity of the binding QDs-Ela quantifies the P-gp expression level. Subsequently, in vitro and in vivo experiments both demonstrate the enhanced multidrug-resistant cancer therapy efficacy, i.e., nanoprobe has 10 times better curative effect than free DOX. In addition, due to the conjugation of FA, the nanoprobe exhibits a selective cell targeting ability to Bel-7402/ADR cells. This nanoplatform paves a new avenue for the accurate treatment of multidrug-resistant cancers.

The selective and quantitative detection of cellular H2O2 is essential for understanding its roles in physiology and pathology. A new electrochemical H2O2 biosensor, fabricated by immobilizing horseradish peroxidase onto dendritic mesoporous silica nanoparticles (HRP/DMSNs), is employed for living cell H2O2 detection. Taking advantage of the large pore volume and highly accessible internal surface areas of DMSNs, HRP/DMSNs display higher enzymatic loading, better stability and bioactivity in comparison with HRP on nonporous silica nanoparticles (NSNs). Therefore, a HRP/DMSN modified GCE (HRP/DMSNs/GCE) shows attractive electrochemical performance for sensitive and selective detection of H2O2 in 0.1 M pH 7.0 PBS, with a low Kappm value of 11.48 μM and a low detection limit of 0.11 μM. In addition, HRP/DMSNs/GCE is successfully applied to detect H2O2 released from a PC12 cell triggered by ascorbic acid (AA). The detected H2O2 amount is close to the reported values. The developed biosensor has potential in the dynamic detection of the flux of H2O2 from living cells for further evaluation of oxidative stress in cells.

MicroRNA (miRNA) is found to be up-regulated in many kinds of cancer and therefore is classified as an oncomiR. Herein, we design a multifunctional fluorescent nanoprobe (FSiNP-AS/MB) with the AS1411 aptamer and a molecular beacon (MB) co-immobilized on the surface of the fluorescent dye-doped silica nanoparticles (FSiNPs) for target-cell-specific delivery and intracellular miRNA imaging. The FSiNPs were prepared by a facile reverse microemulsion method from tetraethoxysilane and silane derivatized coumarin that was previously synthesized by click chemistry. The as-prepared FSiNPs possess uniform size distribution, good optical stability and biocompatibility. In addition, there is a remarkable affinity interaction between the AS1411 aptamer and the nucleolin protein on the cancer cell surface. Thus, a target-cell-specific delivery system by the FSiNP-AS/MB is proposed for effectively transferring a MB into the cancer cells to recognize the target miRNA. Using miRNA-21 in MCF-7 cells (a human breast cancer cell line) as a model, the proposed multifunctional nanosystems not only allow target-cell-specific delivery with the binding affinity of AS1411, but also can track simultaneously the transfected cells and detect intracellular miRNA in situ. The proposed multifunctional nanosystems are a promising platform for a highly sensitive luminescent nonviral vector in biomedical and clinical research.

The development of a nanobody-based electrochemiluminescent immunosensor for procalcitonin quantification is described. A highly specific and enhanced sensitivity of target detection was achieved by CdTe quantum dot encapsulated silica nanoparticle-assisted signal amplification.

A novel glucose sensing strategy by using bi-enzyme coated monodispered silica nanoparticles (SiO2) was proposed. The monodispered SiO2 was synthesized according to our previously reported seed-growth methods. Glucose oxidase (GOD) and horseradish peroxidase (HRP) were simultaneously covalent immobilized on the surface of SiO2 nanoparticles through the cross-linker of glutaraldehyde. The immobilized bi-enzyme remained their bioactivities well for the substrate reaction. Thus, the resultant SiO2-GOD/HRP nanocomposites could be used as catalyst for enzymatic substrate reactions in the presence of 3,3',5,5'-tetramethylbenzidine (TMB) as chromogenic reagent and glucose as substrate. The factors of affecting the catalytic activities of enzymes were optimized. Under optimal conditions, the absorbance at 450 nm in UV-visible spectra increased with the glucose concentration, which could be used for glucose detection with a linear range from 0.5 μM to 250 μM and a detection limit of 0.22 μM at a signal-to-noise ratio of 3σ. Considering the potential of making pills using this SiO2-GOD/HRP, the present strategy has good prospect in the clinic science and other fields in future., (Copyright © 2014 Elsevier B.V. All rights reserved.)

MicroRNAs (miRNAs) has been identified as diagnostic and prognostic biomarkers and predictors of drug response for many diseases, including a broad range of cancers, heart disease, and neurological diseases. The noninvasive theranostics system for miRNAs is very important for diagnosis and therapy of the cellular disease. Herein, a target-cell-specific theranostics nanoprobe for target-cell-specific delivery, cancer cells and intracellular miRNA-21 imaging, and cancer cell growth inhibition was proposed. The nanoprobe (FS-AS/MB) was prepared by simultaneously coupling of the AS1411 aptamer and miRNA-21 molecular beacon (miR-21-MB) onto the surface of Ru(bpy)₃²⁺-encapsulated silica (FS) nanoparticles. The FS nanoparticles synthesized by a facile reverse microemulsion method showed nearly monodisperse spherical shape with a smooth surface, good colloidal stability, a fluorescence quantum yield of ~21%, and low cytotoxicity. The antibiofouling polymer PEG grafted onto a silica shell reduced nonspecific uptake of cells. The ability of FS-AS/MB for target-specific cells delivery, simultaneous cancer cells, intracellular miRNA-21 imaging, and inhibition of miRNA-21 function and suppression of cell growth in vitro, were also demonstrated. The results of the present study suggested that the proposed nanoprobes would be a promising theranostics for different cancers by imaging and inhibiting other intracellular genes.

Nitric oxide synthase (NOS) plays a critical role in a number of key physiological and pathological processes. Investigation of electron-transfer reactions in NOS would contribute to a better understanding of the nitric oxide (NO) synthesis mechanism. Herein, we describe an electrochemically driven catalytic strategy, using a nanocomposite that consisted of the oxygenase domain of neuronal NOS (D290nNOSoxy), indium tin oxide (ITO) nanoparticles and polyvinyl alcohol (PVA). Fast direct electron transfer between electrodes and D290nNOSoxy was observed with the heterogeneous electron transfer rate constant (ket) of 154.8 ± 0.1s(-1) at the scan rate of 5 Vs(-1). Moreover, the substrate N(ω)-hydroxy-L-arginine (NHA) was used to prove the concept of electrochemically driven biocatalysis of D290nNOSoxy. In the presence of the oxygen cosubstrate and tetrahydrobiopterin (BH4) cofactor, the addition of NHA caused the decreases of both oxidation current at +0.1 V and reduction current at potentials ranging from -0.149 V to -0.549 V vs Ag/AgCl. Thereafter, a series of control experiments such as in the absence of BH4 or D290nNOSoxy were performed. All the results demonstrated that D290nNOSoxy biocatalysis was successfully driven by electrodes in the presence of BH4 and oxygen. This novel bioelectronic system showed potential for further investigation of NOS and biosensor applications., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Simultaneous detection of multianalytes associated with a particular cancer is beneficial for disease diagnosis. Here, a facile immunosensing strategy was designed to allow simultaneous electrochemical detection of dual proteins, in a single run. CdSe and PbS water-soluble quantum dots (QDs) were prepared and coated on monodisperse silica nanoparticles as labels for proteins detection. Rabbit immunoglobulin G antigen (IgG) and carcinoembryonic antigen (CEA) were chosen as model proteins for analysis. After a typical sandwich immunoassay, CdSe and PbS QDs labels were introduced onto the Au substrates' surface, which were then dissolved and could be simultaneously monitored by square-wave-voltammetric (SWV) stripping measurements. Under selected conditions, IgG and CEA could be assayed in the ranges of 0.05-40 ng mL(-1) and 0.05-25 ng mL(-1), respectively. The proposed method possessed high sensitivity, good precision, and satisfactory reproducibility and regeneration., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Background: The detection of Epstein-Barr virus-derived latent membrane protein 1 (LMP-1) is essential for understanding its contribution to the development of malignancy in epithelial cells and the early screening of nasopharyngeal carcinoma tumors. It is important to explore novel means for enhancing detection sensitivity of LMP-1., Methods: The current strategy for enhancing sensitivity is based on signal amplification of LMP-1/cadmium telluride (CdTe) quantum dots (QDs) functionalized silica nanosphere labels (Si/QD/Ab2). Si/QD/Ab2 was fabricated by covalently binding LMP-1 antibody (denoted Ab2) to CdTe QDs, which have been previously coated onto the surface of silica nanoparticles with EDC Chemistry. The as-prepared Si/QD/Ab2 label can be brought to a modified gold slice by a "sandwiched" immunoreaction, which was confirmed by SEM images and detected by square wave voltammetry (SWV)., Results: The amount of captured Si/QD/Ab2 by sandwiched immunoreaction was related to the concentration of LMP-1 in the incubation solution. The calibration range for LMP-1 detection was found to be 0.001 to 10 ng/ml with a correlation coefficient of 0.9897 and the lowest detectable concentration of 0.001 ng/ml. Compared with traditional sandwich immunoassay, the detection sensitivity of presented approach was enhanced largely due to the large surface area of silica nanoparticle carriers, which increased in CdTe QDs loading per sandwiched immunoreaction., Conclusion: The ease of functionalization, good monodispersed sizes and uniformity of the silica nanoparticles allows the QDs coated silica nanospheres to be highly suited for immunological labeling of trace protein analysis. The proposed method is simple, selective, reproducible, and can be extended to study protein-protein, peptide-protein, and DNA-protein interaction., (Copyright © 2010 Elsevier B.V. All rights reserved.)

A novel strategy for sensitive detection of biomarkers using horseradish peroxidase (HRP)-functionalized silica nanoparticles as the label is presented. The enzyme-functionalized silica nanoparticles were fabricated by coimmobilization of HRP and alpha-fetoprotein antibody (anti-AFP, the secondary antibody, Ab2), a model protein, onto the surface of SiO(2) nanoparticles using gamma-glycidoxypropyltrimethoxysilane (GPMS) as the linkage. Through "sandwiched" immunoreaction, the enzyme-functionalized silica nanoparticle labels were brought close to the surface of gold substrates, as confirmed by the scanning electron microscopy (SEM) images. Enhanced detection sensitivity was achieved where the large surface area of SiO(2) nanoparticle carriers increased the amount of HRP bound per sandwiched immunoreaction. The electrochemical and chemiluminescence measurement showed 29.5- and 61-fold increases in detection signals, respectively, in comparison with the traditional sandwich immunoassay. The improved particle synthesis using a "seed-particle growth" route yielded particles of narrow size distribution, which allowed consistent loading of HRP and anti-AFP on each microsphere and ensured subsequent immunosensing possessed high sensitivity and reproducibility. This strategy was successfully demonstrated as a simple, cost-effective, specific, and potent method to detect AFP in practical samples.

The selective and quantitative detection of cellular H2O2 is essential for understanding its roles in physiology and pathology. A new electrochemical H2O2 biosensor, fabricated by immobilizing horseradish peroxidase onto dendritic mesoporous silica nanoparticles (HRP/DMSNs), is employed for living cell H2O2 detection. Taking advantage of the large pore volume and highly accessible internal surface areas of DMSNs, HRP/DMSNs display higher enzymatic loading, better stability and bioactivity in comparison with HRP on nonporous silica nanoparticles (NSNs). Therefore, a HRP/DMSN modified GCE (HRP/DMSNs/GCE) shows attractive electrochemical performance for sensitive and selective detection of H2O2 in 0.1 M pH 7.0 PBS, with a low Kappm value of 11.48 μM and a low detection limit of 0.11 μM. In addition, HRP/DMSNs/GCE is successfully applied to detect H2O2 released from a PC12 cell triggered by ascorbic acid (AA). The detected H2O2 amount is close to the reported values. The developed biosensor has potential in the dynamic detection of the flux of H2O2 from living cells for further evaluation of oxidative stress in cells. [ABSTRACT FROM AUTHOR]

Bright blue luminescent graphene quantum dots (GQDs) with major graphitic structured nanocrystals and a photoluminescence (PL) quantum yield of 15.5% were synthesized and used to monitor DNA damage. The GQDs were prepared by ultraviolet irradiation without using a chemical agent. The as-prepared GQDs showed excitation-dependent PL and stable electrochemiluminescence (ECL) behaviors. Gold nanoparticles (AuNPs) were linked with a probe of single-stranded DNA (cp53 ssDNA) to form AuNPs-ssDNA. The ECL signal of the GQDs could be quenched by non-covalent binding of the AuNPs-ssDNA to the GQDs, due to the occurrence of an electrochemiluminescence resonance energy transfer between the GQDs and the AuNPs. When AuNPs-ssDNA was then hybridized with target p53 DNA to form AuNPs-dsDNA, the non-covalent interaction between the GQDs and the ds-DNA weakened and the ECL of the GQDs recovered. This engendered an ECL sensor for the detection of target p53 ssDNA, with a detection limit of 13 nM. The resultant ECL sensor could be used for DNA damage detection based on its different bonding ability to damaged target p53 ssDNA and cp53 ssDNA linked AuNPs. The presented method could be expanded to the development of other ECL biosensors, for the quantification of nucleic acids, single nucleotide polymorphisms or other aptamer-specific biomolecules. [ABSTRACT FROM AUTHOR]

Abstract: An amperometric biosensor for the determination of glycated hemoglobin in human whole blood is proposed. The principle is based on the electrochemical measurement of ferroceneboronic acid (FcBA) that has been specifically bound to the glycated N-terminus. Hemoglobin is immobilized on a zirconium dioxide nanoparticle modified pyrolytic graphite electrode (PGE) in the presence of didodecyldimethylammonium bromide (DDAB). The incubation of this sensor in FcBA solution leads to the formation of an FcBA-modified surface due to the affinity interaction between boronate and the glycated sites of the hemoglobin. The binding of FcBA results in well-defined redox peaks with an E 0′ of 0.299V versus Ag/AgCl (1M KCl). The square wave voltammetric response of the bound FcBA reflects the amount of glycated hemoglobin at the surface. This signal increases linearily with the degree of glycated hemoglobin from 6.8 to 14.0% of total immobilized hemoglobin. The scheme was applied to the determination of the fraction of glycated hemoglobin in whole blood samples. [Copyright &y& Elsevier]

Direct electrochemistry and thermal stability of hemoglobin (Hb) immobilized on a nanometer-sized zirconium dioxide (ZrO2) modified pyrolytic graphite (PG) electrode were studied. The immobilized Hb displayed a couple of stable and well-defined redox peaks with an electron transfer rate constant of (7.90±0.93) s−1 and a formal potential of −0.361 V (−0.12 V versus NHE) in 0.1 M pH 7.0 PBS. Both nanometer-sized ZrO2 and dimethyl sulfoxide (DMSO) could accelerate the electron transfer between Hb and the electrode. Spectroscopy analysis of the Hb/ZrO2/DMSO film showed that the immobilized Hb could retain its natural structure. This modified electrode showed a high thermal stability up to 74 °C and an electrocatalytic activity to the reduction of hydrogen peroxide (H2O2) without the aid of an electron mediator. The electrocatalytic response showed a linear dependence on the H2O2 concentration ranging from 1.5 to 30.2 μM with a detection limit of 0.14 μM at 3σ. The apparent Michaelis–Menten constant KMapp for H2O2 sensor was estimated to be (0.31±0.02) mM, showing a high affinity. [Copyright &y& Elsevier]

The enhanced sensitivity for detection of biomarkers based on CdTe quantum dot functionalized silica nanosphere labels can be achieved by an increase in CdTe QD loading per sandwiched immunoreaction. [ABSTRACT FROM AUTHOR]

Abstract: This is to report a practical and convenient method for 3D macroporous Pt synthesis based on the monodispersion silica template. The silica nanospheres were fabricated using an improved Stöber method. The alternative method of tetraethoxysilane (TEOS) addition to the reaction system was found to be helpful in gaining silica spheres with high monodispersion. The diameter of the final silica spheres increased proportionally with adding TEOS. The silica template was built with the self-assembling method by dispersing a dilute suspension of SiO2 nanosphere onto the smooth Au support surface. After evaporating the solvent naturally, a three-dimensional template with some void spaces around the arranged nanospheres, on the Au slide, was obtained. The macroporous Pt was synthesized by electrodeposition of Pt into the void spaces of the template, which was confirmed by SEM images. The surface activities of the resultant macroporous Pt were investigated by comparing the hydrogen adsorption/desorption peaks in H2SO4 and the methanol oxidation activity. The resultant macroporous Pt displayed high activity level during Pt loading of 0.532mgcm−2. The current work presents a useful method for nanoparticle synthesis, 3D template and macroporous material fabrication. [Copyright &y& Elsevier]

Poly(ADP-ribose) polymerase-1 (PARP-1) activity is closely related to tumor, which is a promising biomarker for cancer diagnosis. So far, only a few methods have been developed for PARP-1 activity assay because both PARP-1 and its catalytic products lack valuable optical or electrochemical property. Herein, we propose a more specific method to label probes on great deal of phosphate groups of PAR. Firstly, versatile peptides were used to prepare CuNPs. This peptide not only worked as reducing agent to prepare CuNPs but also had guanidine groups to label PAR autonomously and specifically. Unlike most previously reported methods based on unspecific electrostatic interactions, CuNPs probes covered by guanidine groups labelled PAR with phosphate groups via intense covalent-like interactions. On the other hand, PARP-1 catalyzed the formation of PAR in each isolated reaction container of the detection array, realizing the high-throughput detection and enhancing the detection efficiency. Ultimately, CuNPs were oxidized into Cu2+ and precisely detected by stripping voltammetry. Hence, selectivity and efficiency of PARP-1 detection were both improved. Meanwhile, this approach was successfully used to detect the efficiency of PARP-1 inhibitor and the PARP-1 contents in real cells, indicating its great potential for clinical diagnosis and high-throughput PARP-1 inhibitor screen. Image 1 • Versatile peptide-templated CuNPs were prepared as probe to recognize PAR. • The covalent-like interaction between peptide and phosphate groups was more specific than usual electrostatic attractions. • Numerous phosphate groups of hyper-branched PAR combined large amount of CuNPs, increasing the detection sensitivity. • Detection array increased the detection efficiency greatly. • This high-throughput biosensor has been applied to detect PARP-1 in cancer cells and to evaluate its inhibition. [ABSTRACT FROM AUTHOR]

[Display omitted] • 3D porous graphene aerogel encapsulating NiCo 2 O 4 decorated carbon nanotubes was applied as anode of Li-ion batteries. • 1D nanotubes crosslinked graphene sheets to form 3D framework with active materials dispersed along the framework. • The structure improved the conductivity and alleviate volume expansion effects. • The anode material exhibited high capacity, superior cycle performance and rate performance for LIBs. The huge volume expansion and poor electrical conductivity have seriously hindered the further development of redox-based electrode materials such as NiCo 2 O 4 (NCO). Herein, we designed a novel NiCo 2 O 4 @nitrogen-doped carbon nanotube@3D graphene (NCO@CT@3DG) aerogel through hydrothermal assembly and high-temperature carbonization. In this aerogel, graphene nanosheets constructed the framework of the aerogel and NCO nanoparticles were deposited on the surface of nitrogen-doped carbon nanotubes which served as active materials for Lithium-ion batteries. The NCO decorated carbon nanotubes connecting the graphene sheets served as the scaffold to support the 3D cross-linked graphene network. As anode material of lithium-ion batteries, the optimized NCO@CT@3DG exhibited excellent electrochemical properties with high capacity as well as superior cycle and rate performance, which could maintain the discharge specific capacity of 810.3 mAh/g at the current density of 1.0 A/g after 500 cycles. The excellent properties are ascribed to the synergistic effect of each individual component and the unique graphene aerogels hybrid structure. This study demonstrates the great application prospects of 3DG aerogel hybrid structure in improving electrochemical properties of active materials with high volume expansion and poor conductivity. [ABSTRACT FROM AUTHOR]

Dysregulation of human tumor necrosis factor α (TNF-α) production has been implicated in a variety of human diseases. Serum level of TNF-α is frequently detected in clinical diagnosis of cancer patients. Herein, we present an ultrasensitive photoelectrochemical (PEC) sandwich immunosensor for TNF-α detection by utilizing anti-TNF-α nanobody (Nb) orientedly immobilized to the CdS and Mn cosensitized TiO 2 nanorod arrays electrode. Using highly oriented Nb as receptor molecules and a secondary anti-TNF-α nanobody conjugated with ZnS nanoparticles as the signal amplification element, the PEC immunosensor for TNF-α was developed by monitoring the changes in the photocurrent intensity of the electrode resulting from immunoreaction. The proposed method has the linear range from 2.0 pg/mL to 200 ng/mL and the detection limit was 1.0 pg/mL. The method also reveals high specificity to detect TNF-α, with acceptable intra-assay precision and excellent stability. The results for the detection of ten serum samples from lung cancer patients and normal human have good agreement with the clinical data. [ABSTRACT FROM AUTHOR]

Nucleoside diphosphatase kinase A (NDPK-A) is a metastasis-suppressor protein and a biomarker that act on a wide range cancer cells to inhibit the potential metastasis. Herein, we present a simple photoelectrochemical immunosensor based on ZnO nanorod arrays for the sensitive detection of NDPK-A. The ZnO nanorod arrays cosensitized with CdS nanoparticles and Mn 2+ displayed a high and stable photocurrent response under irradiation. After anti-NPDK-A nanobodies were immobilized to the ZnO nanorod arrays, the proposed immunosensor can be utilized for detecting NPDK-A by monitoring the changes in the photocurrent signals of the electrode resulting from immunoreaction. Accordingly, the well-designed immunosensor exhibited a low limit of detection (LOD) of 0.3 pg mL −1 and a wide linear range from 0.5 pg mL −1 to 10 μg mL −1 . The R 2 of the regression curve is 0.99782. Meanwhile, the good stability, reproducibility and specificity of the resulting photoelectrochemical biosensor are demonstrated. In addition, the presented work would offer a novel and simple approach for the detection of immunoreactions and provide new insights in popularizing the diagnosis of NPDK-A. [ABSTRACT FROM AUTHOR]

Abstract: A novel colorimetric immunosensing strategy based on protein-modified gold nanoparticle probes combined with atom transfer radical polymerization (ATRP) technology was proposed. Gold nanoparticles (GNPs, ∼15nm) were functionalized with antibodies through an acylamide-bond between the carboxylic group of 11-mercaptoundecanoic acid that previously self-assembled on the surface of GNPs and the amino group of the protein (here, goat anti-rabbit immunoglobulim G (anti-IgG) used as model). The surface functionalized GNPs were used for IgG capture, which introduced initiator coupled anti-IgG (Ab2*) onto the surface of GNPs through immunoreactions. Subsequently triggered polymer growth resulted in the surface graft of preformed polymer chains onto nanoparticles that altered the optical property of GNPs. A distinct color change occurred. This could be designed for IgG detection. The spectrum absorption and colorimetric detection gave a linear range of 0.5–25ngmL−1 with a detection limit of 0.03ngmL−1 for IgG. The proposed approach showed high sensitivity from both visual and absorbance measurements. In spite of the limitations of available IgG antibodies, this approach could be easily extended to the detection of other biomarkers. [Copyright &y& Elsevier]