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In recent years, research on human umbilical cord mesenchymal stem cells (hUCMSCs) derived from human umbilical cord tissue has accelerated and entered clinical application research. Compared with mesenchymal stem cells (MSCs) from other sources, hUCMSCs can be extracted from different parts of umbilical cord or from the whole umbilical cord. It has the characteristics of less ethical controversy, high differentiation potential, strong proliferation ability, efficient expansion in vitro, avoiding immune rejection and immune privilege, and avoids the limitations of lack of embryonic stem cells, heterogeneity, ethical and moral constraints. hUCMSCs avoid the need for embryonic stem cell sources, heterogeneity, and ethical and moral constraints. Bone defects are very common in clinical practice, but completely effective bone tissue regeneration treatment is challenging. Currently, autologous bone transplantation and allogeneic bone transplantation are main treatment approaches in clinical work, but each has different shortcomings, such as limited sources, invasiveness, immune rejection and insufficient osteogenic ability. Therefore, to solve the bottleneck of bone tissue regeneration and repair, a great amount of research has been carried out to explore the clinical advantages of hUCMSCs as seed cells to promote osteogenesis. However, the regulation of osteogenic differentiation of hUCMSCs is an extremely complex process. Although a large number of studies have demonstrated that the role of hUCMSCs in enhancing local bone regeneration and repair through osteogenic differentiation and transplantation into the body involves multiple signaling pathways, there is no relevant article that summarize the findings. This article discusses the osteogenesis-related regulatory mechanisms of hUCMSCs, summarizes the currently known related mechanisms, and speculates on the possible signals. [ABSTRACT FROM AUTHOR]

Stable silver nanosol (AgNP) was prepared by the light-wave procedure. Based on the Galvanic replacement reaction (GRR) of Au(III) on AgNP surface and using Victoria blue B (VBB) as molecular probes, a surface-enhanced Raman scattering (SERS) quantitative analysis of trace Au(III) was developed. VBB has no SERS signal in the dispersed AgNP sol substrate. Addition of NaCl, the VBB produced strong surface-enhanced Raman signals at 1381 cm −1 in the aggregated AgNP sol substrate. When Au(III) is present in the system, the surface Ag atoms interact with Au(III) to form Ag + and Au due to the potential difference, and the Au atom and AgCl deposited on the AgNP surface to reduce the SERS activity significantly and result in SERS signal quenching. The quenched SERS signal is linear to Au(III) concentration in the range of 25–625 nmol/L, with a detection limit of 8 nmol/L. The GRR system can be also monitored by resonance Rayleigh scattering (RRS) spectroscopy, Au can be detected by SERS and RRS methods, and the former is more sensitive. [ABSTRACT FROM AUTHOR]

In pH 5.5 2-( N-morpholino)-ethanosulfonic acid buffer solution containing 0.25 M NaCl at 80 °C, the single-stranded substrate DNA hybridizes with the enzyme DNA to form double-stranded DNA (dsDNA). The substrate chain of dsDNA could be cracked catalytically by UO to produce a short single-stranded DNA (ssDNA) that adsorbed on the nanogold (NG) surface to form a stable nanogold-ssDNA conjugate and then further combine with rhodamine 6G (RhG) to form a NG-ssDNA-RhG conjugate that can be monitored by the surface-enhanced resonance Raman scattering (SERRS) spectral technique at 1,360 cm. Under the selected conditions, the increased SERRS intensity Δ I was linear to UO concentration in the range of 5-125 nmol/L, with a detection limit of 1.6 nmol/L. Using a 0.5-μmol/L Hg as enhancer, a 2.5-100-nmol/L UO can be determined. [ABSTRACT FROM AUTHOR]

exhibited catalytic effect on the cracking reaction of double-stranded DNA (dsDNA) to form a short single-stranded DNA (ssDNA) that protected the nanogold (NG) to produce stable NGssDNA conjugate. The un-protected NG was aggregated to form NG aggregates (NGA) that appeared a resonance scattering (RS) peak at 542 nm. Unlike NGA, the NGssDNA exhibited a strong catalytic activity on the Cu2O particle reaction of Fehling reagent-glucose that can be monitored by RS technique at 608 nm. When theconcentration increased, the NGssDNA increased, and the RS intensity at 608 nm increased. The increased RS intensity ΔI608 nmwas linear to theconcentration in the range of 15–200 pmol L−1, with a regression equation of ΔI608 nm = 1.24 C + 4.6, and a detection limit of 5 pmol L−1. This new RS assay was applied to assayin water sample, with satisfactory results. [ABSTRACT FROM AUTHOR]

In pH 5.5 2-( N-morpholino)-ethanosulfonic acid buffer solution containing 0.0125 M NaCl at 80 °C, the single-stranded substrate DNA hybrid with enzyme DNA to form double-stranded DNA (dDNA). The substrate chain of dDNA could be cracked catalytically by UO to produce a short single-stranded DNA (ssDNA) that adsorbed on the nanogold (NG) surface to form stable NGssDNA conjugate, and the unadsorbed NG take place aggregation to produce the NG aggregations in blue color. Both NG and NGssDNA exhibited strong catalytic activity on the gold particle reaction between HAuCl and ascorbic acid that can be monitored by resonance scattering (RS) spectral technique at 620 nm. However, the catalytic effect of NG aggregation was very weak and it cannot be separated from the cracked reaction solution. When the UO concentration increased, the ssDNA increased, the NGssDNA increased, the formed gold particles increased, and the RS intensity at 620 nm increased. The increased RS intensity Δ I was linear to UO concentration in the range of 3.35-23.45 pM, with a regression equation of Δ I = 27.6 C + 29.1, and detection limit of 0.1 pM. This new RS assay was applied to analysis of UO in water sample with satisfactory results. [ABSTRACT FROM AUTHOR]

In pH 1.99 sodium acetate-HCl buffer solutions at 60 °C, Rhodamine B exhibited a strong fluorescence peak at 584 nm using an excitation wavelength of 548 nm. The fluorescence quenching occurred when FeO nanoparticles catalyzed HO oxidation of Rhodamine B. Under the chosen conditions, the fluorescence intensity at 584 nm decreased when the concentration of HO increased. The fluorescence quenching intensity is linear with the concentration of HO in the range of 10-200 nmol/L. Thus, a new and simple and sensitive nanocatalytic fluorescence method was proposed for the determination of HO in synthetic sample, with satisfactory results. [ABSTRACT FROM AUTHOR]

The resonance scattering spectral probe for Pb was obtained using aptamer-modified AuPd Nanoalloy. In the pH 7.0 NaHPO-NaHPO buffer solution, the aptamer interacted with AuPd nanoalloy particles to form stable aptamer-AuPd nanoalloy probe for Pb that is stable in high concentration of salt. The probe combined with Pb ions to form a G-quadruplex and to release AuPd nanoalloy particles that aggregate to form big particles which led the resonance scattering (RS) intensity enhancing. The reaction solution was filtered by 0.15 μm membrane to obtain the filtration containing aptamer-AuPd nanoalloy probe that has strong catalytic effect on the electrodeless nickel particle plating reaction between Ni(II) and PO that exhibited a strong RS peak at 508 nm. The RS intensity at 508 nm decreased when the Pb concentration increased. The decreased intensity (Δ I) is linear to the concentration of 0.08-42 nM Pb, with regress equation of $$ \Delta {I_{{5}0{\rm{8nm}}}} = {16}.{3}\,c + {1}.{5} $$, correlation coefficient of 0.9965, and detection limit of 0.04 nM Pb. The RS assay was applied to the analysis of Pb in wastewater, with satisfactory results. [ABSTRACT FROM AUTHOR]

Abstract: Single strand DNA (ssDNA) was used to modify nanogold to obtain a nanogold-aptamer resonance scattering (RS) probe (NGssDNA) for Hg2+, based on the formation of stable thymine-Hg2+-thymine (T-Hg2+-T) mismatches and aggregation of the released nanogold particles. After removing the aggregated particles by filtrate membrane, the excess NGssDNA in the filtration solution exhibit catalytic effect on the gold particle reaction between HAuCl4 and ascorbic acid (AA) that appear as RS peak at 596nm. When Hg2+ concentration increased, the RS intensity at 596nm decreased. The decreased intensity is linear to Hg2+ concentration in the range of 0.00008–0.888ng/mL Hg2+, with detection limit of 0.000034ng/mL. The nanogold-aptamer catalytic RS assay was applied to determination of Hg2+ in water with satisfactory results. [Copyright &y& Elsevier]

Abstract: A novel and sensitive resonance scattering (RS) spectral immunoassay for the determination of microalbumin (Malb) was developed, based on the catalytic effect of immunonanogold (ING) probe on Fehling reagent–glucose reaction, and resonance scattering effect of Cu2O particles. Nanogold particles in size of 10nm were used to label goat anti-human microalbumin (GMalb) to obtain an ING probe (AuGMalb) for Malb. The probe produced unspecific aggregation in pH 5.0 citric acid–Na2HPO4 buffer solutions. Upon addition of Malb, the dispersed ING complex formed. The ING complex in supernatant was obtained by centrifuging and was used as catalyst for the reaction between Fehling reagent and glucose to form the Cu2O particles to amplify the resonance scattering signal at 610nm. With addition of Malb, the ING complex in the supernatant increased and the RS intensity at 610nm (I 610nm) enhanced linearly. The enhanced intensity ΔI 610nm was proportional to the Malb concentration in the range of 0.014–0.43ngml−1, with a detection limit of 7.2pgml−1. The proposed method was applied to detect Malb in human urine sample with satisfactory results. [Copyright &y& Elsevier]

Abstract: Nanogold exhibits strong catalytic effect on the slow reaction between glucose and Fehling reagent at 70°C. The production of Cu2O particles have two stronger resonance scattering (RS) peaks at 390nm and 505nm. The catalytic effect of nanogold-labeled goat anti-human IgG (AuIgG) on the reaction was investigated with the RS technique. Coupled the immunoreaction and the immunonanogold catalytic reaction and centrifugal technique, a highly sensitive and selective RS method was developed for the detection of immunoglobulin G (IgG) as a model. With the concentration of IgG increased, the RS intensity at 505nm decreased. The decreased intensity at 505nm ΔI 505 nm was proportional to IgG concentration in the range of 0.13–53.3ngmL−1, with a detection limit of 0.04ngmL−1 IgG. This new immunonanogold–catalytic Cu2O–particle RS bioassay was applied to the determination of IgG in serum sample, with high sensitivity, good selectivity, and low cost. [Copyright &y& Elsevier]

Abstract: Gold nanoparticles in size of about 10nm was used to label goat anti-human complement 3 (anti-C3) to obtain a sensitive and selective immunoresonance scattering spectral probe for C3. It was based on the immune reaction between labeled anti-C3 and C3 in the pH 5.6 Na2HPO4–citric acid buffer solutions and in presence of polyethylene glycol (PEG). The resonance scattering (RS) intensity at 560nm enhanced greatly with C3. Well linear relationships between the enhanced RS intensity (△I RS) and the C3 concentration in the range of 8.33–200ngml−1 were obtained, with a detection limit of 2.8ngml−1 and the limit of quantification 8.51ngml−1 for C3. The convenient and selective and sensitive assay was applied to quantification of C3 in human sera, with satisfactory results. [Copyright &y& Elsevier]

Abstract: Yellow silver nanoparticles in water phase were prepared by microwave synthesis method. Study found that there is a fluorescence peak at 465nm and a strongest resonance scattering peak at 460nm for the nanoparticles. The resonance scattering intensity at 465nm I 460nm. fluorescence intensity at 465nm F 465 nm and absorbance at 455nm A 455nm were found linear to the concentration c Ag in the range from 0 to 3.5×10−4 mol/L Ag, with linear regression equation for I 460nm =48.1×104 cAg +3.69 and F 465nm =28.7×104 c Ag +3.50 and A 455nm1.23×104 c Ag +0.01, their regression coefficient for 0.9976, 0.9954 and 0.9957, respectively. When the c Ag was over 3.5×10−4 mol/L, the resonance scattering peak and fluorescence peak of 465nm take place red-shift and display luminescence quenching, but the absorption peak place does not change and the absorption intensity enhances. The paper reports the spectral properties of silver nanoparticles in water phase, and offers the principle of interface luminescence electron to state the luminescence effect of silver nanoparticles. [Copyright &y& Elsevier]

The Ag cluster in solution has been prepared by a microwave high-pressure procedure. There is a maximum resonance Rayleigh scattering (RRS) peak at 425 nm (7.06×1014 Hz) and a smaller RRS peak at 850 nm (1/2×7.06×1014 Hz) by synchronous scattering at λex=λem. It is a nonlinear optical medium. When scattering the emission wavelength (λem) as the excited wavelength (λex) at 425 nm (7.06×1014 Hz), a maximum RRS peak was observed at 425 nm (7.06×1014 Hz). A 1/2 fraction scattering peak at 850 nm (1/2×7.06×1014 Hz) was also investigated. When λex is at 850 nm (3.53×1014 Hz), a frequency-doubling scattering peak at 425 nm is observed, and a RRS peak is displayed at 850 nm (3.53×1014 Hz). When theλex is two times longer than the maximum RRS wavelength (the strongest wavelength of pump band λpb) of an atomic cluster, a nonlinear scattering frequency-doubling peak (λpb) exhibits at half of the λex, which is stronger than the RRS peak. This phenomenon is defined as pump effect. [ABSTRACT FROM AUTHOR]

A new catalytic kinetic method has been proposed for the determination of Se from 8.0×10−9 to 8.0×10−8 M, using the fact that Se(IV) can catalyze the slow reaction between KClO3 and phenylhydrazine sulfate (PH) in 0.1 M H2SO4 solution at 100 °C. The reduction product of ClO3−, Cl−, reacts with Ag+ to form (AgCl)n nanoparticles. The nanoparticles exhibit a maximum resonance scattering spectral peak at 470 nm. The intensity of resonance scattering light at 470 nm is linear with respect to the Se concentration, using the fixed-reaction time procedure. The factors influencing the determination of Se were examined. This catalytic resonance scattering spectral method has been applied to the analysis of Se in real samples, with satisfactory results. [Copyright &y& Elsevier]

A novel resonance scattering spectral method has been proposed for the determination of trace amounts of chlorides in the range of 2×10−7–8×10−6 mol/l. It was based on the photochemical reaction system of AgNO3–NaCl–sodium oxalic to form the (AgCl)nucleus (n)(Ag)shell (s) nanoparticle. There is a strongest resonance scattering peak at 470 nm and a maximum absorption peak at 425 nm. The concentration of chlorides is proportional to the intensity of resonance scattering at 470 nm. The nonlinear resonance scattering peaks of the nanoparticle system have been also considered, according to the theory of the interaction between the surface electron of nanoparticle and the incidence photon. [Copyright &y& Elsevier]

Nanosilver was modified by aptamer (ssDNA) to obtain a resonance scattering (RS) probe (AgssDNA) for melamine (MA). Based on the catalytic effect of the probe on the Fehling particle reaction, a nanocatalytic RS assay is proposed for the determination of 0.02–1.06 μg L−1MA. [ABSTRACT FROM AUTHOR]

A new, stable and high-catalytic activity ferrocene-doped polystyrene nanosphere (PNFer) sol was prepared by the hydrogel procedure and characterized by electron microscopy and molecular spectroscopy. Results show that the nanosol exhibits excellent catalysis of the new indicator nanoreaction between AgNO3 and sodium formate to generate nanosilver with strong surface-enhanced Raman scattering (SERS), resonance Rayleigh scattering (RRS) and surface plasmon resonance absorption (Abs) trimode molecular spectral signals. This new nanocatalytic amplification trimode indicator reaction was coupled with the G-quadruplex DNAzyme catalytic amplification of Pb2+ aptamer to fabricate a new SERS quantitative/RRS/Abs assay platform for the determination of ultratrace amounts of Pb2+. The Pb2+ content in water samples was analyzed with satisfactory results. [ABSTRACT FROM AUTHOR]

AbstractNanosurface-imprinted polymer nanoprobes (Fe3O4@MIP) were prepared by microwave synthesis using Fe3O4 as a nanosubstrate, aspirin as a template, α-methacrylic acid (MAA) as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linking agent, and 2,2'-azobisisobutyronitrile (AIBN) as an initiator. Characterization of Fe3O4@MIP revealed that the spectral probe exhibited strong resonance Rayleigh scattering (RRS) for aspirin. With the increase in aspirin concentration, the RRS energy transfer (RRS-ET) was enhanced, and the signal at 370 nm decreased, providing a linear range from 0.25 to 12.5 μmol/L and a detection limit (DL) of 0.08 μmol/L. The developed protocol was used for the determination of aspirin in drugs with recoveries from 93.2 to 102.6. [ABSTRACT FROM AUTHOR]

A new coinage metal nanocluster surface molecularly imprinted polymethacrylic acid nanoprobe (NC@MIP) for the selective determination of 2,4,6-trichlorophenol (TCP) was prepared via microwave synthesis using 2,4,6-trichlorophenol as a template molecule, copper nanoclusters (CuNC) as a nanosubstrate, and methacrylic acid as a polymer monomer. It was found that the copper nanocluster MIP (CuNC@MIP) shows the strongest catalytic performance for the reduction of HAuCl4 by hydrazine hydrate for the on-site generation of gold nanoparticles (AuNPs) with the surface plasmon resonance (SPR) effects of resonance surface-enhanced Raman scattering (SERS) and resonance Rayleigh scattering (RRS) as well as absorption (Abs). When TCP was added, the CuNC@MIP nanoprobe and TCP-formed CuNC@MIP–TCP nanoenzyme with stronger catalytic activity generated more AuNPs, and the trimodal analytical signal was enhanced linearly. Therefore, a new SERS/RRS/Abs trimodal sensing platform for TCP was constructed, which was simple, rapid, sensitive, and selective. For each mode, the linear ranges were 0.0075–0.075, 0.010–0.10, and 0.010–0.10 nmol L−1, and the detection limits were 0.0010, 0.021, and 0.043 nmol L−1, respectively. The relative deviation of TCP in different water quality was 0.47%–2.5% and the recovery rate was 94.6%–108.6%. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new Au@MIP difunctional probe was prepared. • The indicator nanoreaction of HAuCl 4 -vanillin was studied. • The probe was not only recognized CAR but also catalyzed the AuNP nanoreaction. • A new SERS/RRS/Abs trimode analytical platform was developed. • The analytical platform was sensitive and selective. Although gold nanoparticle (AuNP) surface molecularly imprinted polymers (Au@MIP) were not fresh, this is of interest to spectral analysts due to their possession of high affinity for the target molecules, strong nanocatalysis to amplify the signals, and good stability to obtain accuracy. New avenues of molecular spectroscopy with straightforward, sensitivity and selectivity can be established using Au@MIP nanosol. In this article, a new carbendazim (CAR) Au@MIP nanocatalytic probe was prepared and the new Au@MIP-CAR-HAuCl 4 -vanillin (VAN) nano indicator reaction was constructed with in situ-generated AuNP as indicator, which with surface-enhanced Raman scattering (SERS), resonance Rayleigh scattering (RRS) and absorption (Abs) effects. Due to space constraints, these imprinted points show high selectivity in the recognition of CAR whose size and shape correspond to the template. The Au@MIP was sensitively detected CAR using SERS/RRS/Abs techniques, with determination range of 0.1–10, 1.5–17.5 and 9.0–30.0 nmol/L, the detection limits of 0.08, 1.0 and 5.0 nmol/L CAR respectively. In addition, the nanocatalytic mechanism was studied. [ABSTRACT FROM AUTHOR]

Malachite green (MG) is highly toxic, persistent, and carcinogenic, and its widespread use is a danger to the ecosystem and a threat to public health and food safety, making it necessary to develop new sensitive multimode molecular spectroscopy methods. In this work, a new copper-based nanomaterial (CuNM) was prepared by a high-temperature roasting using a copper metal–organic framework (CuMOF) as precursor. The as-prepared CuNM was characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy, transmission electron microscopy (TEM), and BET surface area analysis. CuNM was found to catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by H2O2 to produce the oxidation product TMBOX; however, subsequently, the MG aptamer (Apt) could be adsorbed on the CuNM surface by intermolecular interaction, which would inhibit the catalytic performance. After the addition of MG to be tested, the CuNM previously adsorbed by the Apt was transformed into its free state, thus restoring its catalytic activity. This new nanocatalytic indicator reaction could be monitored by surface-enhanced Raman scattering (SERS)/resonance Rayleigh scattering (RRS)/fluorescence (FL)/absorption (Abs) quadruple-mode methods. The SERS determination range was 0.004–0.4 nmol L−1 MG, with a limit of detection of 0.0032 nM. In this way, a rapid, stable, and sensitive method for the determination of MG residues in the environment was established. [ABSTRACT FROM AUTHOR]

The stable Cu 2 O nanocubic (Cu 2 ONC) sol was prepared, based on graphene oxide (GO) catalysis of glucose-Fehling's reagent reaction, and its absorption and resonance Rayleigh scattering (RRS) spectra, transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) were examined. Using the as-prepared Cu 2 ONC as RRS probe, and coupling with the neomycin sulfate (NEO) complex reaction, a new, simple, sensitive and selective RRS-energy transfer (RRS-ET) method was established for detection of neomycin sulfate, with a linear range of 1.4–112 μM and a detection limit of 0.4 μM. The method has been applied to the detection of neomycin sulfate in samples with satisfactory results. [ABSTRACT FROM AUTHOR]

[Display omitted] • Highly catalytic and stable TbMOF@Au was prepared by solvothermal-reduction method. • The new SERS/RRS/Abs catalytic indicator reaction was utilized to amplify signal. • A triple-mode molecular spectral method was developed for MAL. • The detection limit of MAL is as low as 0.21 ng/mL. Terbium metal–organic framework (TbMOF) was prepared by microwave method with 1,3,5-benzenetricarboxylic acid as ligand. With HAuCl 4 as precursor and NaBH 4 as reducing agent, TbMOF-loaded gold nanoparticles (AuNPs) catalyst (TbMOF@Au 1) was prepared rapidly and characterized by transmission electron microscope (TEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. It was found that TbMOF@Au 1 has a strong catalytic effect on the HAuCl 4 -Cys nanoreaction, and the produced AuNPs have a strong resonant Rayleigh scattering (RRS) peak and surface plasmon resonance absorption (Abs) peak at 370 nm and 550 nm, respectively. With the addition of the molecular probe Victoria blue 4R (VB4r), AuNPs have a strong surface-enhanced Raman scattering (SERS) effect, the target analyte molecules are trapped in between the nanoparticles and a hot spot effect created in the process resulting in an extremely high SERS signal. A new SERS/RRS/Abs triple-mode analysis method for Malathion (MAL) was established by coupling this new TbMOF@Au 1 catalytic indicator reaction with MAL aptamer (Apt) reaction, and its SERS detection limit was 0.21 ng/mL. The SERS quantitative analysis method has been applied to the analysis of fruit samples with the recovery of 92.6–106.6 % and the precision of 2.72–8.16 %. [ABSTRACT FROM AUTHOR]

Liquid crystals (LCs) are a very important display material. However, the use of LC, especially LC-loaded nanoparticles, as a catalyst to amplify the analytical signal and coupled with specific aptamer (Apt) as a recognition element to construct a highly sensitive and selective three-mode molecular spectral assay is rarely reported. In this article, five LCs, such as cholesteryl benzoate (CB), were studied by molecular spectroscopy to indicate the liquid crystal nanoparticles in the system, and highly catalytic and stable CB loaded-nanosilver (CB@AgNPs) sol was prepared. The slope procedure was used to study the catalysis of the five LCs and CB@AgNPs on the new indicator reaction between AgNO3 and sodium formate (Fo) to produce silver nanoparticles (AgNPs) with a strong surface plasmon resonance absorption (Abs) peak at 450 nm, a resonance Rayleigh scattering (RRS) peak at 370 nm and a surface enhanced Raman scattering (SERS) peak at 1618 cm−1 in the presence of molecular probes. By coupling the new CB@AgNPs catalytic indicator reaction with the Apt reaction, a new CB@AgNPs catalytic amplification-SERS/RRS/Abs trimode biosensoring platform was constructed for detecting inorganic pollutants, such as Pb2+, Cd2+, Hg2+ and As3+. [ABSTRACT FROM AUTHOR]

A new Fe metal–organic framework-loaded liquid crystal 4-octoxybenzoic acid (FeMOF@OCTB) nanosol was synthesized using 1,3,5-phthalic acid, ferrous sulfate, and OCTB as precursors. The FeMOF@OCTB exhibits good stability and strong catalytic effect for the polyethylene glycol 400-Ag (I) indicator reaction, which was evaluated rapidly by the slope procedure. The generated silver nanoparticles have a strong surface-enhanced Raman scattering (SERS) effect and a surface plasmon resonance absorption (Abs) peak at 420 nm. This new bimodal nanosilver indicator reaction was coupled with the isocarbophos (IPS)-aptamer (Apt) reaction. A FeMOF@OCTB nanocatalytic amplified-SERS/Abs bimodal Apt assay for IPS was established. The SERS assay can detect IPS in the concentration range 0.02–1.2 nM, with a detection limit of 0.010 nM. It has been applied to the determination of IPS in rice samples. The relative standard deviation was 4.4–5.8%, and the recovery was 97.7–104%. An Ag nanosol plasmon SERS/Abs dimode aptamer assay was fabricated for trace isocarbophos, based on highly catalysis MOF@OCTB nanoenzyme. [ABSTRACT FROM AUTHOR]

A new di-recognition nitrogen-doped carbon dot nanosurface aptamer molecularly imprinted polymer (CD NAg @MIPApt) nanocatalytic di-functional probe was prepared by microwave irradiation. The probe was utilized nitrogen-doped silver carbon dots (CD NAg) as the matrix, glyphosate (Gly) as the template molecule, α-methyl acrylate as the monomer, ethylene glycol dimethacrylate as the cross-linker, and aptamer as the biorecognition element. It could not only recognize Gly but also exhibits catalytic amplification function. It was found that CD NAg @MIPApt catalyzed the redox reaction of polyethylene glycol 400 (PEG400)-AgNO 3 to generate silver nanoparticles (AgNPs). The AgNPs indicator component exhibit the effects of surface-enhanced Raman scattering (SERS), resonance Rayleigh scattering (RRS) and surface plasmon resonance absorption (Abs). In the presence of Gly, it binds to the surface imprinted site of CD NAg @MIPApt, to reduce AgNPs generation due to the catalytic activity of CD NAg @MIPApt decreasing. Thus, the SERS/RRS/Abs signal values decreased linearly. The linear ranges of SERS/RRS/Abs assay were 0.1–2.5 nM, 0.25–2.75 nM and 0.5–5 nM respectively. The detection limits were 0.034 nM, 0.071 nM and 0.18 nM Gly. • A new CD NAg @MIPApt probe with di-recognition and di-function was prepared. • Apt was not only enhanced the sensitivity but also improved the selectivity. • The probe exhibits strong catalysis of the new nanoreaction to form AgNPs. • The in situ generated AgNPs are of strong SERS, RRS and Abs effects. • A new, simple, selective and sensitive trimode method for Gly was established. [ABSTRACT FROM AUTHOR]

Endemic fluorosis has gained increasing attention as a public health concern, and the escalating risk of colitis resulting from excessive fluoride intake calls for effective mitigation strategies. This study aimed to investigate the potential mechanisms underlying the alleviation of fluoride-induced colitis by Tea polysaccharides (TPS). Under conditions of excessive fluoride intake, significant changes were observed in the gut microbiota of rats, leading to aggravated colitis. However, the intervention of TPS exerted a notable alleviating effect on colitis symptoms. Antibiotic intervention and fecal microbiota transplantation (FMT) experiments provided evidence that TPS-mediated relief of fluoride-induced colitis is mediated through its effects on the gut microbiota. Furthermore, TPS supplementation was found to modulate the structure of gut microbiota, enhance the relative abundance of Limosilactobacillus vaginalis in the gut microbiota, and promote the expression of short-chain fatty acid (SCFAs) receptors in colonic tissue. Notably, L. vaginalis played a significant role in alleviating fluoride-induced colitis and facilitating the absorption of butyric acid in the rat colon. Subsequent butyric acid intervention experiments confirmed its remarkable alleviating effect on fluoride-induced colitis. Overall, these findings provide a potential preventive strategy for fluoride-induced colitis by TPS intervention, which is mediated by L. vaginalis and butyric acid. [Display omitted] • Tea polysaccharides (TPS) significantly alleviate fluoride-induced colitis in rats. • TPS-mediated relief of fluoride-induced colitis is mediated through its effects on the gut microbiota. • Limosilactobacillus vaginalis is identified as a crucial mediator in alleviating fluoride-induced colitis by TPS. • TPS and L. vaginalis enhance the absorption of butyric acid and up-regulate the colonic expression of GPR41 and GPR43. • TPS holds promise as a preventive and therapeutic approach for fluoride-induced colitis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Liquid crystal trans -4-(3,4-difluorophenyl)-4′-n-pentylbicyclohexyl as resonance Rayleigh scattering probe was studied. • The complex of Cr6+ diphenylcarbazide resulted in the RRS weakening. • The resonance Rayleigh scattering-energy transfer method for Cr6+ is facile and sensitive. Hexavalent chromium (Cr6+) has strong oxidizing property and toxicity. It has been identified as a carcinogen with obvious carcinogenic effect by the International Anti-cancer Research Center. Therefore, it has a great significance to establish a simple and sensitive method for Cr6+. In the solution, liquid crystal (LC) trans, trans -4-(3,4-difluorophenyl)-4′-n-pentylbicyclohexyl (DP) exhibits strong resonance Rayleigh scattering (RRS) effect due to formation DP nanoparticles. It was used firstly as nanoprobe, to establish a simple and sensitive RRS energy transfer (RRS-ET) method for the determination of trace Cr6+ in water samples. The Cr6+ reacts with diphenylcarbazide (DCB) to produce purple complex. It is adsorbed on the nanoprobe surface, the purple complex as energy receptor and DP as energy donor to produce RRS-ET phenomenon, to make the RRS signal of 370 nm decreasing. In the range of 3–30 nmol/L Cr6+, with the increase of concentration, the RRS signal decreased linearly at 370 nm, with a detection limit of 0.49 nmol/L. This new RRS-ET method was applied to the determination of Cr6+ in water samples, with recovery of 96.0–104.7% and the relative standard deviation (RSD) of 4.44–9.98%. [ABSTRACT FROM AUTHOR]

A neodymium metal–organic framework (MOFNd) was prepared using 1H-pyrazole-3,5-dicarboxylic acid (H3pdc) and 2-pyrazinecarboxylic acid as ligands. Through the addition of HAuCl4 as a precursor and NaBH4 as a reducing agent, a new MOFNd-loaded nanogold (AuNPs) (Au@MOFNd) nanosol with good stability and high catalytic activity was conveniently prepared via a solvothermal-reduction method and characterized. It was found that the indicator reaction of reducing HAuCl4 by Na2SO3 to generate AuNPs was slow. Au@MOFNd strongly catalyzes this nanoreaction, and the produced AuNPs exhibit a strong resonance Rayleigh scattering (RRS) peak at 370 nm, and a strong surface-enhanced Raman scattering (SERS) peak at 1617 cm−1 with the addition of the molecular probe Victoria blue 4R (VB4r). A novel SERS/RRS di-mode quantitative analysis method for glyphosate (GLY) was established by coupling this new Au@MOFNd catalytic indicator reaction with the aptamer (Apt) reaction of GLY, with SERS and RRS detection limits of 0.02 nM and 0.3 nM, respectively. It has been applied to the analysis of soil samples with a recovery rate of 93.0%–106.5% and precision of 2.2%–4.1%, and the results were satisfactory. [ABSTRACT FROM AUTHOR]

Background: The incidence of adenocarcinoma of the esophagogastric junction (AEG) has rapidly increased in recent years. Popular surgical approaches for AEG are proximal gastrectomy (PG) and total gastrectomy (TG), but it is controversial as to which approach is superior. Therefore, we conducted a systematic review and meta-analysis to evaluate the short- and long-term clinical outcomes of PG and TG for AEG. Methods: PubMed, Embase, Web of Science, and Cochrane Library were searched from inception to 1 June 2021. The Newcastle–Ottawa scale was used to conduct quality assessments, and RevMan (Version 5.4) was used to perform the meta-analysis. Results: In all, 1,734 patients with Siewert II/III AEG in 12 studies were included in the meta-analysis. PG was associated with less number of harvested lymph nodes (WMD = − 9.00, 95% CI − 12.61 to − 5.39, P < 0.00001), smaller tumor size (WMD = − 1.02, 95% CI − 1.71 to − 0.33, P = 0.004), shorter hospital length of stay (WMD = − 3.99, 95% CI − 7.27 to − 0.71, P = 0.02), and better long-term nutritional status compared with TG. Overall complications, other complications, and overall survival were not significantly different between the two groups. Moreover, subgroup analysis revealed that the occurrence of anastomotic strictures and reflux esophagitis was associated with the use of novel gastrointestinal tract (GI) anastomoses (double-tract reconstruction, jejunal interposition, and semi-embedded valve anastomosis) after PG. Conclusions: Based on the available evidence, we recommend that surgeons accept PG combined with multiple novel anastomoses as an optimal surgical approach in patients diagnosed with resectable Siewert type II/III AEG. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel magnetic nanosurface MIP nanoprobe (Fe 3 O 4 @MIP) was synthesized. • Fe 3 O 4 @MIP efficiently catalyzed the AuNP reaction of HAuCl 4 -fructose. • A sensitive SERS/RRS dimode method was established with Fe 3 O 4 @MIP probe. • Fe 3 O 4 @MIP can be separated by magnet, to improve the sensitivity. Three functional magnetic nanocatalytic probe, which integrates recognition, catalytic amplification, and separation enrichment, is a new approach to construct a simple, fast, highly selective, and sensitive analytical method. In this article, a new magnetic nanosurface molecularly imprinted polymer nanoprobe (Fe 3 O 4 @MIP) with trifunctionality was rapidly prepared using a microwave-assisted method with magnetic Fe 3 O 4 nanoparticles as a substrate, chloramphenicol (CAP) as a template molecule, and methacrylic acid as a functional monomer. The characterized nanoprobe was found that could specifically recognize CAP, strongly catalyze the new indicator nanoreaction of fructose (DF)-HAuCl 4. The gold nanoparticles (AuNPs) exhibit strong resonance Rayleigh scattering (RRS) and surface enhanced Raman scattering (SERS) effects. Upon addition of CAP, the SERS/RRS signals were linearly weakened. Accordingly, a new SERS/RRS analysis platform for highly sensitive and selective determination of CAP was constructed. The SERS linear range was 0.0125–0.1 nmol/L, with detection limit (DL) of 0.004 nmol/L CAP. Furthermore, it could be combined with magnet-enriched separation to further improve the sensitivity, with a DL of 0.04 pmol/L CAP. The SERS method has been used for the determination of CAP in real samples, with relative standard deviations of 2.37–9.89 % and the recovery of 95.24–107.1 %. [ABSTRACT FROM AUTHOR]

Highlights: [•] O3 oxidize I− to produce . [•] react with victoria blue B to form association particle. [•] The RRS peak intensity is linear with O3 concentration. [•] The method is simple, fast and sensitive. [ABSTRACT FROM AUTHOR]

A simple, sensitive and selective RRS method for the determination of Cr(VI) with nanosurface molecularly imprinted polyacrylamide nanoprobe. [Display omitted] • A new AgNCs@MIP nanoprobe was prepared with Ag nanocluster as substrate. • The nanoprobe can recognize chromate to cause RRS signal decreasing. • A selective and sensitive RRS method was established for determination of trace chromate. This article was used potassium dichromate as the template molecule, silver nanoclusters as the nano matrix, acrylamide as the monomer, ethylene glycol dimethacrylate (EGDMA) as the crosslinking agent, and azodiisobutyronitrile (AIBN) as the initiator to prepare a new silver nanocluster surface MIP (AgNCs@MIP) nanoprobe for chromate. Upon addition of Cr(VI), it selectively adsorbs on the surface of AgNCs@MIP nanoprobes. The dichromate ion absorption peak at 350 nm overlaps with the AgNCs@MIP RRS peak at 370 nm, resulting in strong RRS energy transfer (RRS-ET) and a decrease in the RRS intensity. The decreased RRS intensity is directly proportional to the concentration of dichromate ions in the range of 0.0025–0.015 µmol/L, with a detection limit of 0.8 nmol/L. Therefore, a simple, fast, sensitive and selective RRS method for the determination of trace Cr(VI) in mineral water has been established, with a relative standard deviation of 9.2–9.8 % and recovery of 95.20 %—103.60 %. [ABSTRACT FROM AUTHOR]

• Highly catalytic PdMOF and di-functional PdMOF@MIP probe were prepared. • The nanoprobe exhibits recognition of OTC and catalysis of HAuCl 4 -NaH 2 PO 2 to generate AuNPs. • The in situ generated AuNPs as indicator can be monitoring by SERS. • A trimode molecular spectral method for ultratrace oxytetracycline was established. • The SERS method is of simplicity, high sensitivity and selectivity. In this paper, a new Pd metal organic framework (PdMOF) surface molecularly imprinted polyaniline nanocatalytic probe (PdMOF@MIP) with dual functions of recognition and catalysis was synthesized. It is found that the PdMOF@MIP nanoprobe can not only identify OTC but also catalyze the new nanoreaction of NaH 2 PO 2 -HAuCl 4 to generate gold nanoparticles (AuNPs), and the generated AuNPs could be traced by surface-enhanced Raman scattering (SERS). When OTC specifically binds to PdMOF@MIP to generate PdMOF@MIP-OTC conjugate, its catalytic effect is weakened and the analytical signal is reduced linaerly. Accordingly, a new, highly sensitive, selective and simple SERS/RRS/Abs trimode detection platform for OTC was constructed. The linear range of SERS was 0.0625 ng/mL ∼ 1.75 ng/mL and the limit of detection was 0.015 ng/mL. This new nanocatalytic probe detection strategy can also be used for the selective detection of other antibiotics such as tetracycline and doxycycline, respectively. In addition, the nanocatalytic mechanism has been investigated. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) can be prepared from various organic (abundant) compounds that are rich in surfaces with –OH, –COOH, and –NH2 groups. Therefore, CDs exhibit good biocompatibility and electron transfer ability, allowing flexible surface modification and accelerated electron transfer during catalysis. Herein, CDs were prepared using a hydrothermal method with fructose, saccharose, and citric acid as C sources and urea as an N dopant. The as-prepared CDs were used to catalyze AgNO3–trisodium citrate (TSC) to produce Ag nanoparticles (AgNPs). The surface-enhanced Raman scattering (SERS) intensity increased with the increasing CDs concentration with Victoria blue B (VBB) as a signal molecule. The CDs exhibited a strong catalytic activity, with the highest activity shown by fructose-based CDs. After N doping, catalytic performance improved; with the passivation of a wrapped aptamer, the electron transfer was effectively disrupted (retarded). This resulted in the inhibition of the reaction and a decrease in the SERS intensity. When bisphenol A (BPA) was added, it specifically bound to the aptamer and CDs were released, recovering catalytical activity. The SERS intensity increased with BPA over the concentration range of 0.33–66.67 nmol/L. Thus, the aptamer-adjusted nanocatalytic SERS method can be applied for BPA detection. [ABSTRACT FROM AUTHOR]

In pH 3.1 HCOOH-HCOONa buffer solution, liquid crystal 5CB was used as the probe to generate a strong resonance Rayleigh scattering (RRS) peak at 450 nm. Gold nanoparticles (AuNPs) could catalyse the reaction of phosphomolybdic acid (PMo)-formic acid (FA) to form phosphomolybdenum blue (PMoB), which caused the RRS strength of PMo at 450 nm to decrease linearly. Hg2+ could have an electrostatic substitution reaction with AuNPs, thereby inhibiting the catalytic effect of AuNPs, and the RRS peak was enhanced. In the range of 2.5 × 10−9 mol/L–4.5 × 10−8 mol/L Hg2+, as the concentration of Hg2+ increased, the catalytic effect of AuNPs gradually weakened, and the peak value of RRS at 450 nm (ΔI) was linearly increased. The regression equation is ΔI450nm = 27.988C−5.6159, and the detection limit is 1.0 nmol/L. The method has been used to detect Hg2+ in wastewater with satisfactory results. [ABSTRACT FROM AUTHOR]

Highly sensitive and selective resonance Rayleigh scattering (RRS) and surface enhanced resonance Raman scattering (SERRS) spectral detection technique are developed by combining the functional nucleic acid including aptamer and DNAzyme, and nanoparticle such as gold/silver (NG/NS) aggregation and catalysis reaction. The recent progress of resonance scattering spectral technologies including RRS and SERRS are reviewed in this paper. [ABSTRACT FROM AUTHOR]

Abstract: The 5nm nanosilver was prepared by the sodium borohydride procedure, using sodium citrate as a stabilizing reagent. The nanosilver particle was combined with the aptamer for K+ to form aptamer–nanosilver complex that was stabile in pH 7.0 Na2HPO4–NaH2PO4 buffer solutions and in the presence of high concentration of NaCl. In 85°C water bath, K+ interacted with the aptamer to form very stable G-quadruplex that cannot stabilize the nanosilver particle. The uncombined nanosilver particles are aggregated to big particles in high concentration of NaCl, that led to the resonance scattering (RS) intensity at 470nm increased greatly. Under the selected conditions, the increased RS intensity (ΔI) is linear to K+ concentration in the range of 0.060–3350μmol/L, with a regression equation of ΔI =0.177C +0.55, a correlation coefficient of 0.9964, and a detection limit of 0.006μmol/L K+. The aptamer–nanosilver RS assay has been applied to determination of K+ in serum and rain water, with satisfactory results. [Copyright &y& Elsevier]

Abstract: Gold nanoparticles in diameter of 10nm were used to label rabbit anti-human chorionic gonadotrophin (RhCG) antiserum to obtain a resonance scattering spectral probe (AuRhCG) for human chorionic gonadotrophin (hCG). The immunoreaction between AuRhCG and hCG take place to form hCG–AuRhCG immunocomplex in pH 5.0 citric acid–Na2HPO4 buffer solution. The immunocomplex solutions were centrifuged to obtain the supernatant solution. The AuRhCG in the supernatant solution exhibited strong catalytic effect on the particle reaction between Ag+ and hydroquinone to produce gold–silver composite particles in pH 3.4 citric acid–trisodium citrate buffer solution. There is a stronger resonance scattering (RS) peak at 423nm for the particles. With the addition of hCG, the AuRhCG in the supernatant solution decreased, and the RS intensity at 423nm decreased. The decreased RS intensity ΔI 423nm was proportional to the concentration of hCG in the range of 2.5–208.3mIU/mL with a detection limit of 0.83mIU/mL. This method has been applied to the determination of hCG in urine samples, with satisfactory results. [Copyright &y& Elsevier]

Abstract: A gold-labeled immunoresonance scattering spectral probe for trace prealbumin (PA) was prepared by using gold nanoparticles in size of 9.0nm to label goat anti-human prealbumin polyclonal antibody. The immune reaction between the gold-labeled antibody and prealbumin took place in pH 7.6 Na2HPO4–NaH2PO4 buffer solution. In the presence of polyethylene glycol PEG-10000, the labeled gold nanoparticles were released and aggregated which brought the resonance scattering intensity (I RS) at 580nm to enhance greatly. The ΔI RS is proportional to the prealbumin concentration in the range from 16.67 to 666.67ng/mL, with a detection limit of 4.1ng/mL. This simple, sensitive and selective assay was applied to determination of prealbumin in human plasma, with satisfactory results. [Copyright &y& Elsevier]

A new gold nanosol SERS method for ultratrace atrazine by a difunctional surface molecular imprinted polymethacrylate probe. [Display omitted] • A new AuNP@MIP nanoprobe was prepared. • The nanoprobe not only has recognition function but also has catalytic function. • The new nano indicator reaction of glyoxal-HAuCl 4 is in situ generated AuNP. • A new SESR sensor platform was created for ultratrace ATZ. A new type of bifunctional nanosurface molecularly imprinted polymer nanoprobe (Au@MIP) was prepared using methacrylic acid as functional monomers respectively, gold nanoparticles (AuNP) as nanosubstrate. The Au@MIP nanoprobe not only has recognition function but also has catalytic function. The findings demonstrate that the AuNP@MIP nanoprobes, prepared with methacrylic acid as the functional monomer, very strongly catalyzed the new nano indicator reaction of glyoxal (GO)-HAuCl 4. In situ generated AuNP sol exhibits strong surface-enhanced Raman scattering (SESR) effects. After adding atrazine (ATZ), the signals were significantly boosted. As a result, a new SESR trimode sensor platform was created for ultratrace ATZ. The linear ranges for ATZ was 0.005–0.0625 nmol/L, with detection limits of 0.0012 nmol/L. Moreover, the SERS method was used to determine the content of ATZ in corn samples, achieving relative standard deviations (RSDs) of 6.53–9.57 % and recoveries of 96.4 %–108.2 %. [ABSTRACT FROM AUTHOR]

• Liquid crystal nanosurface imprinted polymers were prepared by microwave procedure. • CBU@MIP not only recognized ML but also catalyzed the new nanogold indicator reaction of HAuCl 4 -SF. • A SERS and RRS dimode analytical platform was established for ultratrace ML. • The SERS/RRS platform has high sensitivity, selectivity and accuracy. In this paper, a new dimode scattering spectral method for rapid detection of ultratrace melamine (ML) in dairy products was established by coupling nanosurface molecular imprinting technology with nanocatalytic amplification reaction of liquid crystal particles. It was found that liquid crystal cholesteryl butyrate (CBU) nanosurface imprinted polymers (CBU@MIP) not only recognized ML but also catalyzed the nano indicator reaction of HAuCl 4 -sodium formate to produce gold nanoparticles with surface-enhanced Raman scattering (SERS) and resonance Rayleigh scattering (RRS) effect. When ML was added, it specifically combined with CBU@MIP to form CBU@MIP-ML conjugates with strong catalytic activity, and SERS and RRS signals increased linearly with the detection limits of 0.0072 pmol/L and 0.093 pmol/L respectively. The method was applied to the determination of ML in dairy products and plastic tablewares with relative standard deviation (RSD) of 2.2–4.4 % and 1.6–4.7 %, and recovery of 95.4 %-108.3 % and 95.9–108.6 % respectively. [ABSTRACT FROM AUTHOR]

A novel highly active silver single-atom catalyst (AgSAC) was prepared by a microwave-assisted solvothermal method using silver covalent organic frameworks (AgMOF) as precursors. It was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), infrared (IR), and surface-enhanced Raman scattering (SERS). The experiment found that AgSAC has excellent catalytic performance and can heavily catalyze the nano-reaction of chloroauric acid-malic acid (HAuCl 4 –H 2 Mi) to generate gold nanoparticles (AuNPs). The produced AuNPs have strong SERS, resonance Rayleigh scattering (RRS) and surface plasmon resonance absorption (Abs) signals. Aflatoxin B1 aptamer (Apt AFB1) can be adsorbed to the surface of AgSAC through electrostatic interaction, to reduce the catalytic activity of AgSAC and the SERS/RRS/Abs signal of the system. When the target molecule (AFB1) was added, it will specifically bind to Apt AFB1 and release AgSAC, restoring the catalytic activity of AgSAC, thereby restoring the SERS/RRS/Abs signal of the system. Based on this, a simple and sensitive aptamer sensing analysis platform for trace AFB1 was established, and a reasonable catalytic amplification mechanism of AgSAC was proposed. The SERS method exhibited the highest sensitivity, with a linear range of 0.005–0.225 μg/L and a detection limit of 0.002 μg/L. Principle of aptamer-mediated SERS/RRS for AFB1 based on AgSAC catalysis. [Display omitted] • A highly active silver single-atom catalyst (AgSAC) was synthesized with AgMOF. • A new AgSAC-HAuCl 4 -H 2 Mi catalytic indicator was constructed. • The nanocatalytic amplification reaction was coupled with aptamer mediation. • A highly sensitive SERS/RRS platform was proposed for trace Aflatoxin B1. [ABSTRACT FROM AUTHOR]

The N and Fe doped carbon dot (CD NFe) was prepared by microwave procedure. Using CD NFe as the nano-substrate, fipronil (FL) as the template molecule and α-methacrylic acid as the functional monomer, the molecular imprinted polymethacrylic acid nanoprobe (CD NFe @MIP) with difunction was synthesized by microwave procedure. The CD NFe @MIP was characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier infrared spectroscopy, and other techniques. The results show that the nanoprobe not only distinguish FL but also has a strong catalytic effect on the HAuCl 4 –Na 2 C 2 O 4 nanogold indicator reaction. When the nanoprobes specifically recognize FL, their catalytic effect is significantly reduced. Since the AuNPs generated by HAuCl 4 reduction have strong surface-enhanced Raman scattering (SERS) and resonance Rayleigh scattering (RRS) effects, a SERS/RRS dual-mode sensing platform for detecting 5–500 ng/L FL was constructed. The new analytical method was applied to detect FL in food samples with a relative standard deviation (RSD) of 3.3–8.1 % and a recovery rate of 94.6–104.5 %. [Display omitted] • A new N/Fe doped carbon dot nanosurface molecularly imprinted polymethacrylate nanoprobe (CD NFe @MIP) was synthesized. • CD NFe @MIP can strongly catalyze the reaction of HAuCl 4 –Na 2 C 2 O 4 system to generate the indicator product AuNPs. • A SERS/RRS dual-mode sensing platform was established coupling the AuNPs reaction with CD NFe @MIP specific recognition. • The SERS/RRS platform has high sensitivity, selectivity and accuracy. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA), as a typical endocrine disruptor, poses a serious threat to human health. Therefore, it is urgent to establish a rapid, sensitive, and simple method for the determination of BPA. In this paper, based on the aptamer-mediated single-atom Fe carbon dot catalyst (SAFe) catalyzing the HAuCl4-ethylene glycol (EG) nanoreaction, a new SERS/RRS di-mode detection method for BPA was established. The results show that SAFe exhibits a strong catalytic effect on the HAuCl4-EG nanoreaction, which could generate purple gold nanoparticles (AuNPs) with resonance Rayleigh scattering (RRS) signals and surface-enhanced Raman scattering (SERS) effects. After the addition of BPA aptamer (Apt), it could encapsulate SAFe through intermolecular interaction, thus inhibiting its catalytic action, resulting in the reduction of AuNPs generated and the decrease of RRS and SERS signals of the system. With the addition of BPA, Apt was specifically combined with BPA, and SAFe was re-released to restore the catalytic ability; the generated AuNPs increased. As a result of this RRS and SERS signals of the system recovered, and their increment was linear with the concentration of BPA. Thus, the quantification of 0.1–4.0 nM (RRS) and 0.1–12.0 nM (SERS) BPA was realized, and the detection limits were 0.08 nM and 0.03 nM, respectively. At the same time, we used molecular spectroscopy and electron microscopy to study the SAFe-HAuCl4-ethylene glycol indicator reaction, and proposed a reasonable SAFe catalytic reaction mechanism. [ABSTRACT FROM AUTHOR]

At temperature of 75 °C, the ethanol-HAuCl4 reaction to generate gold nanoparticles is relatively slow (AuNPs), and the noble metal nanoparticles can catalyze this nanoreaction. Sulfite can reduce PdCl2-H2PtCl6 to generate PtPd nanoalloy (PtPd) and strong catalysis to generate red AuNPs, which has a strong RRS peak at 370 nm. When Victoria blue 4R (VB4R) is added, it produced a strong SERS peak at 1617 cm−1. We use SERS, RRS, absorption spectroscopy, electron microscopy, and other techniques to study the catalytic reaction of PtPd nanoalloy and propose a new mechanism for the nanoalloy catalytic reactions. When the SO32−concentration in the system gradually increases, the AuNPs produced by the catalytic reaction gradually increase and the RRS/SERS peak intensity increases linearly. Based on the nanoalloy catalytic amplification strategy, a new and sensitive RRS/SERS coupled dual-mode detection method for SO32− was constructed, with linear range of 0.13–12.1 μg·L−1 and a DL of 0.02 μg·L−1. [ABSTRACT FROM AUTHOR]

In the hybrid communication scenario of the Heterogeneous Cloud Radio Access Network and Device-to-Device in 5G, spectrum efficiency promotion and the interference controlling caused by spectrum reuse are still challenges. In this article, a novel resource management method, consisting of power and channel allocation, is proposed to solve this problem. An optimization model to maximum the system throughput and spectrum efficiency of the system, which is constrained by Signal to Interference plus Noise Ratio requirements of all users in diverse layers, is established. To solve the non-convex mixed integer nonlinear optimization problem, the optimization model is decomposed into two sub-problems, which are all solvable quasi-convex power allocation and non-convex channel allocation. The first step is to solve a power allocation problem based on solid geometric programming with the vertex search method. Then, a channel allocation constructed by three-dimensional hypergraph matching is established, and the best result of this problem is obtained by a heuristic greed algorithm based on the bipartite conflict graph and µ -claw search. Finally, the simulation results show that the proposed scheme improves the throughput performance at least 6% over other algorithms. [ABSTRACT FROM AUTHOR]

New multifunctional nanomaterial preparation and its application to trace pollutant analysis are interesting to peoples. Using terbium metal-organic framework loaded gold nanoparticles (MOF Tb @Au) as the nanosubstrate and 3-aminopropyltriethoxysilane (APTES) as the functional monomer, a new bifunctional nanosurface molecularly imprinted polymer nanoprobe of MOF Tb @Au@MIP with strongly recognition and catalytic amplification functions was prepared by the microwave sol-gel procedure. It was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier infrared spectroscopy (FTIR) and other techniques. The nanoprobe was found to specifically recognize malathion (MAL) and catalyze the L-cysteine (Cys)-HAuCl 4 nanogold indicator reaction to amplify the molecular spectral signal. The gold nanoparticles (AuNPs) generated in the system show a strong surface-enhanced Raman scattering (SERS) effect, resonant Rayleigh scattering (RRS) peak and UV absorption (Abs) peak at 1615 cm−1, 370 nm and 520 nm, respectively. Based on this, a new SERS/RRS/Abs trimode method for the detection of MAL can be established. It has been applied to the analysis of cereal samples with satisfactory recoveries of 95.2–107.4% and precision of 3.76–9.06%. [Display omitted] • A new SMIP was synthesized with nanosubstrate of MOF@AuNP. • The SMIP has recognition and catalytic amplification difunction. • A new HAuCl 4 -cysteine-SMIP nanocatalytic indicator reaction was discovered. • A new SERS/RRS/Abs trimode analytical platform was developed to determine malathion. [ABSTRACT FROM AUTHOR]

[Display omitted] • Highly catalytic and stable CD N was prepared by microwave hydrothermal method. • A new dual-mode SERS/RRS method was developed for Pb2+. • The detection limit of Pb2+ is as low as 0.11 nmol/L. Nitrogen-doped carbon dots (CD N) were prepared by microwave hydrothermal method using ammonium citrate (AC) and ethylenediaminetetraacetic acid (EDTA) as precursor. It was characterized by transmission electron microscopy (TEM) and infrared spectroscopy (IR). The CD N was found to catalyze the reduction of HAuCl 4 to produce gold nanoparticles (AuNP), among which fructose was an effective reducing agent. Using malachite green (MG) as a molecular probe, the surface enhanced Raman scattering (SERS) intensity at 1617 cm−1 and the resonance Rayleigh scattering (RRS) intensity at 375 nm increased linearly with increasing CD N concentration, respectively. The catalytic activity of CD N is inhibited because the aptamer (Apt) can be adsorbed on the surface of the catalyst CD N. The aptamer (Apt)-Pb2+ reaction and CD N -Apt adsorbing reaction were competitive reaction. When there is Pb2+ that binds more tightly to Apt, Apt is desorbed, and the catalytic ability of CD N is restored. Accordingly, an Apt-mediated nanocatalytic amplification SERS/RRS platform for quantitative detection of lead ions was constructed. For the SERS method, the linear range was 0.5–120 nmol/L with DL of 0.11 nmol/L. For the RRS method, the Pb2+ concentration was linear in the range of 50–400 nmol/L with the RRS intensity, and the DL was 15.32 nmol/L. The analysis platform uses CD N catalyzed nanoreactions to generate AuNP products with SERS activity as a substrate, thus overcoming the shortcomings of Pb2+ without scattering activity, and realizing the possibility of SERS and RRS detection of metal ions. It was used for the determination of Pb2+ in real samples with relative standard deviations were 0.94–2.71 % and recovery was 99.00–103.70 %, respectively. In addition, the mechanism of CD N nanoenzyme heterogeneous catalysis of nano-gold reactions was discussed. [ABSTRACT FROM AUTHOR]

A fluorometric clenbuterol immunoassay is described that uses S- and N-co-doped carbon quantum dots as the fluorescent probe. Strongly fluorescent S/N-doped carbon quantum dots (S/N-CDs) were synthesized by hydrothermal method using fructose as the carbon precursor and L-cysteine as S/N sources. The S/N-CDs were characterized by transmission electron microscopy, energy dispersive spectroscopy and Fourier transform infrared spectroscopy (FTIR). Under 350 nm photoexcitation, they display strong purple fluorescence with an emission peak at 405 nm. In pH 4.0 solution, the amino groups (confirmed by FTIR) on the carbon quantum dots were coupled to clenbuterol antibody (Ab) by amine–amine coupling reaction to quench the fluorescence. If clenbuterol (Clen) is added, it binds to the Ab to generate a stable Ab-Clen immunocomplex and free S/N-CD. This causes the fluorescence of nanoprobe to be restored. The fluorescence of the system increases linearly in the 0.07–1.7 ng·mL−1 Clen concentration range. The probe of type S/N4-CD displays the best sensitivity. The detection limit is 23 pg·mL−1. [ABSTRACT FROM AUTHOR]