Ag+-doped boron quantum dots with enhanced stability and fluorescence enabling versatile practicality in visual detection, sensing, imaging and photocatalytic degradation

In this work, a metal-doping strategy was put forward to construct metal-doped borophene and the corresponding zero-dimensional boron. Through theoretical calculations, Ag⁺ acts as the optimal metal ions to prepare Ag⁺-doped borophene derived boron quantum dots (Ag-BQDs). As predicted theoretically, doping of Ag⁺ endows borophene with enhanced stability of electronic structures. The newly emerging Ag-BQDs were experimentally acquired from ultrasonic-assisted liquid-phase exfoliation of bulk boron and solvothermal treatments. According to theoretical and experimental studies, the improved stability and fluorescence (FL) of Ag-BQDs are due to the formation of strong B-Ag bonding to competitively suppress B-O bonding. The function enables the maximal protection of borophene electronic structures from oxidization, destruction and reconfiguration. Because of Ag-BQDs with relatively higher colloidal and FL stability over BQDs, potential applications of Ag-BQDs were further explored in promising fields toward FL visualization in aqueous solutions and on filter paper, employed as a chemosensor of Fe³⁺ for FL sensing and visual detection at the solid/liquid phases, utilized for multiple FL bio-imaging at the levels of fresh plants, live animals and live cells of fresh plants, and applied to photocatalytic degradation of organic dyes and anticancer drug. Experimental results demonstrate excellent performances of Ag-BQDs in multiple applications, including versatile FL sensing and visual detection, unique multi-channel FL bio-imaging and visible-light-driven photodegradation of organic pollutants, toxic and harmful substances. This work can promote the development of metal-ion-doped low- dimensional nanomaterials with improved stability and FL properties for significant applications.

Ratiometric upconversion luminescence nanoprobes from construction to sensing, imaging, and phototherapeutics

In terms of the combined advantages of upconversion luminescence (UCL) properties and dual-signal ratiometric outputs toward specific targets, the ratiometric UCL nanoprobes exhibit significant applications. This review summarizes and discusses the recent advances in ratiometric UCL nanoprobes, mainly including the construction of nanoprobe systems for sensing, imaging, and phototherapeutics. First, the construction strategies are introduced, involving different types of nanoprobe systems, construction methods, and ratiometric dual-signal modes. Then, the sensing applications are summarized, involving types of targets, sensing mechanisms, sensing targets, and naked-eye visual detection of UCL colors. Afterward, the phototherapeutic applications are discussed, including bio-toxicity, bio-distribution, biosensing, and bioimaging at the level of living cells and small animals, and biomedicine therapy. Particularly, each section is commented on by discussing the state-of-the-art relevant studies on ratiometric UCL nanoprobe systems. Moreover, the current status, challenges, and perspectives in the forthcoming studies are discussed. This review facilitates the exploration of functionally luminescent nanoprobes for excellent sensing, imaging, biomedicine, and multiple applications in significant fields.

Metal-Doped Boron Quantum Dots for Versatile Detection of Lactate and Fluorescence Bioimaging

To improve the stability and fluorescence (FL) of monoelemental boron nanomaterials, this work put forward a metal-coordination strategy to explore emerging metal-doped boron quantum dots, Co@BQDs. Through theoretical calculations, B-Co bonding as predicted can suppress the B-O reaction and protect the electronic structures of exfoliated two-dimensional (2D) boron from oxidation and decomposition upon exposure to oxygen. In experimental studies, Co²⁺ was added into a dispersion liquid of bulk boron and subjected to probe sonication to promote Co²⁺ adsorption on the surface of exfoliated 2D boron, followed by Co²⁺ coordination with exposed boron atoms. Solvothermal treatment of exfoliated 2D boron resulted in the generation of Co²⁺-doped 0D boron Co@BQDs. Experimental results confirm that Co@BQDs have higher colloidal and FL stability than BQDs as a reference. B-Co bonding formation to suppress the B-O reaction ensures the high stability of exfoliated boron structures. A dispersion liquid of Co@BQDs with stable and bright FL was used for visual FL imaging of solutions and solid substrates. Based on enzymatic and cascade oxidation-induced FL quenching of Co@BQDs, a novel FL bio-probe of lactate was explored. This bio-probe, with a broad detection range of 0.01-10 mM and a low detection limit of 3.1 μM, enables FL sensing of lactate in biosamples and shows high detection recoveries of 98.0-102.8%. Moreover, this bio-probe realized versatile FL imaging and visual detection of lactate in liquid/solid-phase systems. These results demonstrate great prospects of Co@BQDs as emerging and efficient imaging reagents for long-term tracking and bioimaging applications.

Monoelemental two-dimensional boron nanomaterials beyond theoretical simulations: From experimental preparation, functionalized modification to practical applications

During the past decade, there is an explosive growth of theoretical and computational studies on 2D boron-based nanomaterials. In terms of extensive predictions from theoretical simulations, borophene, boron nanosheets and 2D boron derivatives show excellent structural, electronic, photonic and nonlinear optical characteristics, and potential applications in a wide range of fields. In recent years, previous studies have reported the successful experimental preparations, superior properties, multi-functionalized modifications of various 2D boron and its derivatives, which show many practical applications in significant fields. To further promote the ever-increasing experimental studies, this present review systematically summarizes recent progress on experimental preparation methods, functionalized modification strategies and practical applications of 2D boron-based nanomaterials and multifunctional derivatives. Firstly, this review summarizes the experimental preparation methods, including molecular beam epitaxy, chemical vapor deposition, liquid-phase exfoliation, chemical reaction, and other auxiliary methods. Then, various strategies for functionalized modification are introduced overall, focusing on borophene derivatives, boron-based nanosheets, atom-introduced, chemically-functionalized borophene and boron nanosheets, borophene or boron nanosheet-based heterostructures, and other functionalized 2D boron nanomaterials. Subsequently, various potential applications are discussed in detail, involving energy storage, catalysis conversion, photonics, optoelectronics, sensors, bio-imaging, biomedicine therapy, and adsorption. We comment the state-of-the-art related studies concisely, and also discuss the current status, probable challenges and perspectives rationally. This review is timely, comprehensive, in-depth and highly attractive for scientists from multiple disciplines and scientific fields, and can facilitate further development of advanced functional low-dimensional nanomaterials and multi-functionalized systems toward high-performance practical applications in significant fields.

A petal-shaped MOF assembled with a gold nanocage and urate oxidase used as an artificial enzyme nanohybrid for tandem catalysis and dual-channel biosensing

A facile one-pot precipitation method was employed to prepare a petal-shaped hybrid under mild conditions. The hybrid is composed of urate oxidase (UOx) encapsulated into a zeolite-like metal-organic framework (MOF) with the doping of a hollow gold nanocage (AuNC). As one of the MOF-enzyme composites, a UOx@MOF(AuNC) hybrid with the features of artificial nanoenzymes was developed as a novel dual-channel biosensing platform for fluorescence (FL) and electrochemical detection of uric acid (UA). As for FL biosensing, enzymatic catalysis of the hybrid in the presence of UA triggered tandem catalysis and oxidation reactions to cause FL quenching. UA was linearly detected in the 0.1-10 μM and 10-300 μM ranges, with the limit of detection (LOD) of 20 nM. As for electrochemical biosensing, the hybrid was dropped on a glassy carbon electrode (GCE) surface to construct a hybrid/GCE platform. Based on the redox reaction of UA on the platform surface, UA was linearly detected in the 0.05-55 μM range, with a LOD of 15 nM. Experimental results confirmed that the hybrid-based dual-channel biosensing platform enabled selective and sensitive responses to UA over potential interferents. The platform has an excellent detection capability in physiological samples. The dual-channel biosensing platform facilitates the exploration of new bioanalysis techniques for early clinical diagnosis of diseases.

Emerging metal ion-coordinated black phosphorus nanosheets and black phosphorus quantum dots with excellent stabilities

In this work, emerging metal ion-coordinated black phosphorus nanosheets (M@BPNSs) and quantum dots (M@BPQDs) were prepared via the sonication-assisted liquid-phase exfoliation of bulk black phosphorus (BP) crystals in the presence of a metal ion (M) and solvothermal reaction of the exfoliated few-layer M@BP nanosheets. Based on theoretical calculations, a bonding mode exists between M and BP. Consequently, the adsorption energies of M on BP via the bonding mode are lower than that of M on BP via the non-bonding mode. Under the bonding mode, the adsorption energy of Zn2+ (-2.04 eV) on BP is lower than other M. Zn2+, serves as the preferred M and can be easily adsorbed on the surface of BP. We experimentally prepared emerging M@BPNSs and M@BPQDs, characterized, and compared various morphologies, microstructures and spectra under different conditions. It is verified, that the surface coordination of M with BP protects BP from oxidization and degradation of its nanostructures upon exposure to O2 and H2O. In comparison to the bare BPNSs, Zn@BPNSs showed high microstructural stability. Moreover, in comparison to bare BPQDs, Zn@BPQDs exhibited high colloidal stability and excellent stabilities with fluorescence and photothermal conversion performances. The long-term stabilities are due to the M-coordination with BP through P-M bonding on BP nanostructures. Thus, the excellent long-term stabilities in microstructure, fluorescence and photothermal conversion levels endow the emerging two-dimensional M@BPNSs and zero-dimensional M@BPQDs with great prospects towards promising applications, especially in electronics, optoelectronics, optical and biomedical fields.

Mn-Doping-induced hierarchical petal growth of a flower-like 3D MOF assembled with black phosphorous nanosheets as an electrochemical aptasensor of human stress-induced phosphoprotein 1

Herein, we report the preparation of Mn-doped Ni-based metal-organic frameworks (Mn-MOF) with 3D hierarchical flower-like superstructures through solvothermal synthesis. The Mn-MOF was assembled with 2D black phosphorous nanosheets (BPNSs) to achieve novel 2D/3D BPNSs/Mn-MOF nanocomposites, followed by the direct coupling of methylene blue (MB)-labeled DNA aptamer on the interface of the nanocomposites-modified glassy carbon electrode (GCE). The aptamer/BPNSs/Mn-MOF/GCE platform was utilized for the capture and efficient detection of stress-induced phosphoprotein 1 (STIP1). Experimental results confirmed that Mn-doping-induced the hierarchical petal growth of the flower-like 3D MOF and its assembly with BPNSs. GCE surface modifications with various components were studied by measuring electrochemical curves. The morphologies, microstructures and spectra of products were characterized. The optimal conditions used for electrochemical measurements were assessed. A smart aptasensor was explored by the aptamer/BPNSs/Mn-MOF/GCE that had multiple attractive merits, including synergistic effects of components, porous superstructures of hierarchical flower-like 3D Mn-MOF and specific aptamer-target recognition. The merits endowed this aptasensor with selective and sensitive signal responses to STIP1 over interferences. This aptasensor enabled the efficient detection of STIP1 in a broad range of 2 × 10^-3-1 × 10⁴ ng mL^-1, accompanied by a low limit of detection of 1 pg mL^-1. This aptasensor realized the successful determination of STIP1 in practical samples, exhibiting high reliability and practicability.

Assembly of Black Phosphorus Nanosheets and MOF to Form Functional Hybrid Thin-Film for Precise Protein Capture, Dual-Signal and Intrinsic Self-Calibration Sensing of Specific Cancer-Derived Exosomes

As the emerging and noninvasive biomarkers, exosomes play an important role in cancer screening, cancer-related immune response, and the physiological process. The sensitive, specific, and efficient detection of cancer cell-derived exosomes is of significance for early cancer diagnosis of patients. This work developed a novel dual-signal and intrinsic self-calibration aptasensor of exosomes based on a functional hybrid thin-film platform. This platform was constructed via facile assembly of black phosphorus nanosheets (BPNSs) and ferrocene (Fc)-doped metal-organic frameworks (ZIF-67) on indium tin oxide (ITO) slice, followed by combining methylene blue (MB)-labeled single- strand DNA aptamer on ITO slice. The resultant aptamer-BPNSs/Fc/ZIF-67/ITO platform had dual redox-signal responses of MB (labeled on aptamer) and Fc (doped into ZIF-67). In the presence of specific cancer cell-derived exosomes, the redox current of MB regularly reduced and that of Fc (as reference) hardly changed. An intrinsic self-calibration aptasensor was achieved and enabled sensitive detection of exosomes, showing a limit of detection down to 100 particles mL^-1. The aptasensor with a capability of precise protein capture can efficiently determine specific cancer cell-derived exosomes in practical human serum and plasma samples from healthy individuals and breast cancer patients. In light of excellent performances, this aptasensor can be expanded to multiple biomarkers from cell line exosomes and is beneficial for exploring advanced techniques for high-performance detection of exosomes derived from different types of cancer cells. This work promotes the development of current techniques for early cancer screening and clinical diagnosis.

Preparation and applications of electrochemical chemosensors based on carbon-nanomaterial-modified molecularly imprinted polymers

The past few decades have witnessed a rapid development in electrochemical chemosensors (ECCSs). The integration of carbon nanomaterials (CNMs) and molecularly imprinted polymers (MIPs) has endowed ECCSs with high selectivity and sensitivity toward target detection. Due to the integrated merits of MIPs and CNMs, CNM-modified MIPs as ECCSs have been widely reported and have excellent detection applications. This review systematically summarized the general categories, preparation strategies, and applications of ECCSs based on CNM-modified MIPs. The categories include CNM-modified MIPs often hybridized with various materials and CNM-encapsulated or CNM-combined imprinting silica and polymers on working electrodes or other substrates. The preparation strategies include the polymerization of MIPs on CNM-modified substrates, co-polymerization of MIPs and CNMs on substrates, drop-casting of MIPs on CNM-modified substrates, self-assembly of CNMs/MIP complexes on substrates, and so forth. We discussed the in situ polymerization, electro-polymerization, and engineering structures of CNM-modified MIPs. With regard to potential applications, we elaborated the detection mechanisms, signal transducer modes, target types, and electrochemical sensing of targets in real samples. In addition, this review discussed the present status, challenges, and prospects of CNM-modified MIP-based ECCSs. This comprehensive review is desirable for scientists from broad research fields and can promote the further development of MIP-based functional materials, CNM-based hybrid materials, advanced composites, and hybrid materials.

Melamine-Induced Decomposition and Anti-FRET Effect from a Self-Assembled Complex of Rhodamine 6G and DNA-Stabilized Silver Nanoclusters Used for Dual-Emitting Ratiometric and Naked-Eye-Visible Fluorescence Detection

In this work, blue-emitting silver nanoclusters (AgNCs) were prepared in a matrix of single-stranded deoxyribonucleic acid (DNA) on the basis of ambient hydrothermal reactions. DNA acted as the stabilizer or coating agent, and NaBH₄ was used as the reducing agent. Through the interactions between rhodamine 6G (Rh6G) and the synthesized DNA-AgNCs, the self-assembled complex of DNA-AgNC-Rh6G was generated. Meanwhile, fluorescence emission of AgNCs was weakened as a result of fluorescence-resonance-energy transfer (FRET) from AgNCs (donor) to Rh6G (acceptor). In the DNA-AgNC-Rh6G complex aqueous suspension, the addition of melamine induced obvious emission recovery of AgNCs and fluorescence decrease of Rh6G, attributable to melamine-induced decomposition of the self-assembled complex and anti-FRET effects. There was a well-plotted linear relationship of ratiometric fluorescence intensities ( I_AgNCs/ I_Rh6G) versus melamine concentration in the range of 0.1-10 μM, with a low detection limit of 25 nM. Responses of I_AgNCs/ I_Rh6G to melamine were highly selective and sensitive over potential interferents. A novel dual-emitting ratiometric fluorescence sensor of melamine was facilely constructed on the basis of the DNA-AgNC-Rh6G complex. In particular, the sensor enabled visual fluorescence detection of melamine both in aqueous solution and on wetted filter paper. Superior detection results of the sensor were experimentally obtained and confirmed its high feasibility for melamine detection in practical samples.

Reduced graphene oxide/nile blue/gold nanoparticles complex-modified glassy carbon electrode used as a sensitive and label-free aptasensor for ratiometric electrochemical sensing of dopamine

In this work, glassy carbon electrode (GCE) surface was modified by drop-coating graphene oxide (GO) and nile blue (NB) to form GO/NB/GCE. By using a one-step coreduction treatment under cyclic voltammetry (CV) scanning, gold nanoparticles (AuNPs) were electrodeposited onto GO/NB/GCE surface, simultaneously generating reduced GO (rGO). AuNPs from the prepared rGO/NB/AuNPs/GCE was combined with 5'-SH-terminated aptamer of dopamine (DA) via Au-S coupling to fabricate aptamer-rGO/NB/AuNPs/GCE system. DA specifically combined with its aptamer modified on rGO/NB/AuNPs/GCE surface. CV, electrochemical impedance spectroscopy, square wave voltammetry responses of this system as the working electrode were measured. With the addition of DA, the peak current intensities located at -0.45 V (I_NB) and 0.15 V (I_DA) showed gradually decreased and increased changes, respectively. There was a good linear (R² = 0.9922) relationship between lg(I_DA/I_NB) and the logarithm of DA concentration (lgC_DA) in the C_DA range from 10 nM to 0.2 mM, showing a low detection limit of 1 nM. This system as a novel, sensitive and label-free aptasensor was used for ratiometric electrochemical sensing of DA. Experimental results verified that this aptasensor possessed high stability, selectivity and sensitivity towards DA detection, over potential interferents. This aptasensor efficiently determined DA in real biological samples, together with high detection recoveries of 97.0-104.0%.

A bimetallic nanoparticle/graphene oxide/thionine composite-modified glassy carbon electrode used as a facile ratiometric electrochemical sensor for sensitive uric acid determination

A novel and facile ratiometric electrochemical sensor was developed for sensitive determination of uric acid.

Specific enzymatic synthesis of 2,3-diaminophenazine and copper nanoclusters used for dual-emission ratiometric and naked-eye visual fluorescence sensing of choline

This work reports a novel biosensor for dual-emission ratiometric and visual fluorescence detection of choline.

Ratiometric fluorescence, solution-phase and filter-paper visualization detection of ciprofloxacin based on dual-emitting carbon dot/silicon dot hybrids

This study demonstrates the ratiometric fluorescence, solution-phase and filter-paper visual detection of ciprofloxacin based on dual-emitting carbon dot/silicon dot hybrids.

Black phosphorus quantum dots: synthesis, properties, functionalized modification and applications

This review article provides the first systematic summary of zero-dimensional black phosphorus quantum dots, from their synthetic methods, properties, and functionalized modification to their applications.

RETRACTED: Facilely self-assembled magnetic nanoparticles/aptamer/carbon dots nanocomposites for highly sensitive up-conversion fluorescence turn-on detection of tetrodotoxin

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor following concerns raised by a reader. The article uses two electron micrographs which have been used in other publications as well, denoting different samples. Fig. 1A is identical to Fig. 3E in RSC Adv., 2013,3, 20959-20969 doi: 10.1039/C3RA43120G despite describing different samples. Fig. 2A is identical to Fig. 1B in Sensors & Actuators B: Chemical, vol 245, pp 386-394 https://doi.org/10.1016/j.snb.2017.01.166 and Fig. 1A in Materials Letters vol 195 pp 131-135 https://doi.org/10.1016/j.matlet.2017.02.119 despite describing different samples. These problems with the data presented cast doubt on all the data, and accordingly also the conclusions based on that data, in this publication. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process., http://dx.doi.org/10.1016/j.talanta.2017.08.043.

Facile construction of reduced graphene oxide–carbon dot complex embedded molecularly imprinted polymers for dual-amplification and selective electrochemical sensing of rutoside

This article reported reduced graphene oxide–carbon dot embedded molecularly imprinted polymers for sensitive and selective electrochemical sensing of rutoside.

Glycerol-regulated facile synthesis and targeted cell imaging of highly luminescent Ag2Te quantum dots with tunable near-infrared emission

In this work, highly luminescent and emission tunable Ag2Te quantum dots (QDs) were facilely prepared by using water-dispersed glycerol as viscous solvent and CH3COOAg/Na2TeO3 as Ag/Te precursors. Viscous glycerol was utilized to slow the nucleation and growth of QDs at 200°C, and enabled the isolation of QDs with different emission wavelengths. Experimental results revealed that the as-prepared Ag2Te QDs exhibited tunable near-infrared emission from 930 to 1084nm, high photoluminescence (PL) quantum yields (QYs, more than 20%), good photostability and low cytotoxicity. After surface coating of a thin silica shell (∼1.4nm), the resulting NH2 terminated Ag2Te@SiO2-NH2 displayed enhanced PL QYs, higher photostability and biocompatibility when compared with the original Ag2Te QDs. Through a facile carboxy-amine coupling, folic acid (FA) was grafted with Ag2Te@SiO2-NH2 to form Ag2Te@SiO2-FA nanocomposites, which were used for targeted PL imaging of folate receptor over-expressed tumor cells.

Retraction: N, S co-doped graphene quantum dots from a single source precursor used for photodynamic cancer therapy under two-photon excitation

Retraction of ‘N, S co-doped graphene quantum dots from a single source precursor used for photodynamic cancer therapy under two-photon excitation’ by Rijun Gui et al., Chem. Commun., DOI: 10.1039/C4CC09280E.

A plasmonic aptasensor for ultrasensitive detection of thrombin via arrested rolling circle amplification

A sensitive signal generation mechanism for gold nanoparticle growth by reducing gold ions with hydrogen peroxide is applied in a plasmonic aptasensor, achieving naked-eye detection of thrombin at the single-molecule level based on the specific interaction of aptamer-thrombin via an arrested rolling circle amplification to yield horseradish peroxidase (HRP)-mimicking DNAzymes as biocatalysts.

Retracted Article: CuS nanocrystal@microgel nanocomposites for light-regulated release of dual-drugs and chemo-photothermal synergistic therapy in vitro

This article reported the facile synthesis of CuS nanocrystal@microgel nanocomposites that were further developed towards the light-regulated release of dual-drugs and chemo-photothermal synergistic therapy in vitro.

Carbon nanomaterials-based electrochemical aptasensors

Carbon nanomaterials (CNMs) have attracted increasing attention due to their unique electrical, optical, thermal, mechanical and chemical properties. CNMs are extensively applied in electronic, optoelectronic, photovoltaic and sensing devices fields, especially in bioassay technology. These excellent properties significantly depend on not only the functional atomic structures of CNMs, but also the interactions with other materials, such as gold nanoparticles, SiO2, chitosan, etc. This review systematically summarizes applications of CNMs in electrochemical aptasensors (ECASs). Firstly, definition and development of ECASs are introduced. Secondly, different ways of ECASs about working principles, classification and construction of CNMs are illustrated. Thirdly, the applications of different CNMs used in ECASs are discussed. In this review, different types of CNMs are involved such as carbon nanotubes, graphene, graphene oxide, etc. Besides, the newly emerging CNMs and CNMs-based composites are also discoursed. Finally, we demonstrate the future prospects of CNMs-based ECASs, and some suggestions about the near future development of CNMs-based ECASs are highlighted.

Aptamer-functionalized hydrogel as effective anti-cancer drugs delivery agents

An aptamer-functionalized hydrogel has been developed, which can be regulated by the AS1411 aptamer with the sol-gel conversion. Also the hydrogel can be further utilized for the controlled encapsulation and release of the cancer drugs. Specially, the AS1411 initiates the hybridization of acrydite-modified oligonucleotides to form the hydrogels and the presence of the target protein nucleolin leads the gel to dissolve as a result of reducing the cross-linking density by competitive target-aptamer binding. Based on the rheology of hydrogels, it is possible to utilize this material for storing and releasing molecules. In this research, the cancer drug doxorubicin is encapsulated inside the gel during the formation of the hydrogel and then released in the presence of nucleolin. Further experiments are carried out to prove the specific recognition of target matter. In vitro researches confirm that the aptamer-functionalized hydrogels can be used as drug carriers in targeted therapy and other biotechnological applications.

Room-temperature phosphorescence logic gates developed from nucleic acid functionalized carbon dots and graphene oxide

Room-temperature phosphorescence (RTP) logic gates were developed using capture ssDNA (cDNA) modified carbon dots and graphene oxide (GO). The experimental results suggested the feasibility of these developed RTP-based "OR", "INHIBIT" and "OR-INHIBIT" logic gate operations, using Hg(2+), target ssDNA (tDNA) and doxorubicin (DOX) as inputs.

HER-2-induced PI3K signaling pathway was involved in the pathogenesis of gastric cancer

Human epidermal growth factor receptor-2 (HER-2) overexpression was closely associated with the tumor growth and invasion, we here aimed to investigate the mechanism of HER-2 mediation in the pathogenesis of gastric cancer (GC). We first detected the expression of HER-2 in GC cell line SGC-7901 and then examined the levels of nuclear factor-κB (NF-κB), matrix metalloproteinase-9 (MMP-9) and intercellular adhesion molecule-1 (ICAM-1) and the association between them by molecular methods. Statistical analysis was used to compare the significance. We further detected the possible molecular mechanism involved in their relationship in the SGC-7901 genesis. The MMP-9, NF-κB and secretory type (s-ICAM-1) levels were significantly greater in peripheral blood serum from SGC-7901 than healthy control GES-1 (P<0.01). ICAM-1, MMP-9 and NF-κB mRNA and protein levels were more highly expressed in SGC-7901 than healthy control GES-1. The expression levels of NF-κB, MMP-9 and ICAM-1 were positively related in GC cell line SGC-7901, which was HER-2 positive. The HER-2 positive SGC-7901 secreted more transforming growth factor beta 1 (TGF-β1) and resultantly activated MMP-9 to enhance s-ICAM-1 secretion and further studies showed that phosphatidylinositol-3 kinase (PI3K)/Akt/NF-κB signaling pathway was involved in GC pathogenesis. The GC cells that express the HER-2 oncogene spur the activation of NF-κB that can upregulate the expression of ICAM-1 and induce the expression of MMP-9, which hydrolyzes ICAM-1 into s-ICAM-1 to promote tumor immune escape. TGF-β1-induced PI3K/Akt/NF-κB signaling pathway was involved in the pathogenesis of GC and they could be a new target for cancer therapy. The GC cells that express the HER-2 oncogene spur the activation of NF-κB that can upregulate the expression of ICAM-1 and induce the expression of MMP-9, which hydrolyzes ICAM-1 into s-ICAM-1 to promote tumor immune escape. TGF-β1-induced PI3K/Akt/NF-κB signaling pathway was involved in the pathogenesis of GC and they could be a new target for cancer therapy.

N, S co-doped graphene quantum dots from a single source precursor used for photodynamic cancer therapy under two-photon excitation

Using polythiophene derivatives as single source precursors, nitrogen (N) and sulfur (S) co-doped graphene quantum dots (NS-GQD) were prepared. Under two-photon excitation (800 nm), the NS-GQD exhibited excellent photostability and high (1)O2 generation, and therefore were developed as photodynamic therapy agents for cancer treatment.

An electrochemical sensor for the sensitive detection of rutin based on a novel composite of activated silica gel and graphene

A novel sensor based on a silica gel–graphene composite for sensitive and selective detection of rutin.

Retracted Article: Facile fabrication of water-dispersible AgInS2 quantum dots and mesoporous AgInS2 nanospheres with visible photoluminescence

This article reported the facile preparation of water-dispersible near-infrared-emitting AgInS₂ quantum dots and mesoporous AgInS₂ nanospheres with visible photoluminescence.

Two-photon excited quantum dots with compact surface coatings of polymer ligands used as an upconversion luminescent probe for dopamine detection in biological fluids

Two-photon excited CdTe quantum dots were developed as a novel upconversion luminescent probe for dopamine detection in biological fluids.

Electrodeposition of PtNi bimetallic nanoparticles on three-dimensional graphene for highly efficient methanol oxidation

In the present work, platinum–nickel (PtNi) bimetallic nanoparticles with a uniform diameter of 40 nm were anchored onto a three-dimensional graphene (3DGN) by using the method of electrodeposition.

Single electrode biosensor for simultaneous determination of interferon gamma and lysozyme

Simultaneous detection of multiple biomarkers holds great promise for acute leukemia evaluation. Here, a novel biosensor is developed for simultaneous electrochemical detection of interferon gamma (IFN-γ) and lysozyme (Lys) based on aptamer recognition by coupling "signal-on" and "signal-off" modes. On one Au electrode, two kinds of signaling probes labeled by the thiolated ferrocene (Fc)- and methy blue (MB)- were designed to hybridize with IFN-γ and Lys aptamers respectively to form partial complementary DNA duplexes. In the presence of IFN-γ and Lys, the target-aptamer interaction led to the release of aptamer from duplex DNA structure. The single-stranded signaling probes thus suffered from the conformation changes, which resulted in the decreased (or increased) oxidation peak current of Fc (or MB) according to the "signal-off (or signal-on)" mode. Electrodes were characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under the optimized conditions, the signal changes were quantified using square wave voltammetry (SWV). This proposed biosensor for IFN-γ and Lys possessed linear detection range from 0.01 to 10 nM and 0.1 to 100 nM, with the detection limits of 1.14×10(-3) nM and 0.0164 nM, respectively. Moreover, this biosensor was readily regenerated and proved successful toward the practical analysis. The proposed strategy could provide more integrated and reliable information for acute leukemia evaluation.

Water-soluble multidentate polymers compactly coating Ag2S quantum dots with minimized hydrodynamic size and bright emission tunable from red to second near-infrared region

Hydrodynamic size-minimized quantum dots (QDs) have outstanding physicochemical properties for applications in multicolor molecular and cellular imaging at the level of single molecules and nanoparticles. In this study, we have reported the aqueous synthesis of Ag2S QDs by using thiol-based multidentate polymers as capping reagents. By regulating the composition of the precursors (AgNO3 and sulfur-N2H4·H2O complex) and multidentate polymers (poly(acrylic acid)-graft-cysteamine-graft-ethylenediamine), as well as the reaction time, Ag2S QDs (2.6-3.7 nm) are prepared, displaying tunable photoluminescence (PL) emission from red to the second near-infrared region (687-1096 nm). The small hydrodynamic thickness (1.6-1.9 nm) of the multidentate polymers yields a highly compact coating for the QDs, which results in the bright fluorescent QDs with high PL quantum yields (QYs: 14.2-16.4%). Experimental results confirm that the QDs have high PL stability and ultralow cytotoxicity, as well as high PLQYs and small hydrodynamic sizes (4.5-5.6 nm) similar to fluorescent proteins (27-30 kDa), indicating the feasibility of highly effective PL imaging in cells and living animals.