Endofungal bacteria and ectomycorrhizal fungi synergistically promote the absorption of organic phosphorus in Pinus massoniana.

Ectomycorrhizal fungi (ECMFs) that are involved in phosphorus mobilisation and turnover have limited ability to mineralise phytate alone. The endofungal bacteria in the ectomycorrhizal fruiting body may contribute to achieving this ecological function of ECMFs. We investigated the synergistic effect and mechanisms of endofungal bacteria and ECMF Suillus grevillea on phytate mineralisation. The results showed that soluble phosphorus content in the combined system of endofungal bacterium Cedecea lapagei and S. grevillea was 1.8 times higher than the sum of C. lapagei and S. grevillea alone treatment under the phytate mineralisation experiment. The S. grevillea could first chemotactically assist C. lapagei in adhering to the surface of S. grevillea. Then, the mineralisation of phytate was synergistically promoted by increasing the biomass of C. lapagei and the phosphatase and phytase activities of S. grevillea. The expression of genes related to chemotaxis, colonisation, and proliferation of C. lapagei and genes related to phosphatase and phytase activity of S. grevillea was also significantly upregulated. Furthermore, in the pot experiment, we verified that there might exist a ternary symbiotic system in the natural forest in which endofungal bacteria and ECMFs could synergistically promote phytate uptake in the plant Pinus massoniana via the ectomycorrhizal system.

A Cuproptosis-Related LncRNA Risk Model for Predicting Prognosis and Immunotherapeutic Efficacy in Patients with Hepatocellular Carcinoma.

Cuproptosis is a novel programmed cell death pathway that is initiated by direct binding of copper to lipoylated tricarboxylic acid (TCA) cycle proteins. Recent studies have demonstrated that cuproptosis-related genes regulate tumorigenesis. However, the potential role and clinical significance of cuproptosis-related long noncoding RNAs (lncRNAs) in hepatocellular carcinoma (HCC) have not been established. We performed a bioinformatics analyses of RNA-sequencing data of HCC patients extracted from The Cancer Genome Atlas (TCGA) dataset to identify and validate a cuproptosis-related lncRNA prognostic signature. Furthermore, we analyzed the clinical significance of the prognostic signature of cuproptosis-related lncRNA in predicting the immunotherapeutic efficacy and the status of the tumor immune microenvironment. The RNA-sequencing data, genomic mutations, and clinical information were downloaded for 374 HCC samples and 50 normal liver samples from TCGA-Liver Hepatocellular Carcinoma (TCGA-LIHC) dataset. Co-expression analysis of Gene-lncRNA pairs with 49 known cuproptosis-related prognostic genes was used to define cuproptosis-related prognostic lncRNAs. We performed the LASSO algorithm and univariate and multivariate Cox regression analysis, respectively, to gradually identify the prognostic risk models of cuproptosis-related lncRNA based on the TCGA-LIHC dataset. Subsequently, the predictive performance of the model was evaluated using receiver operation characteristic (ROC) curves, Kaplan-Meier survival curves, and prognostic nomogram. The analysis of gene-lncRNA co-expression with 49 known cuproptosis-related genes identified 1359 cuproptosis-related lncRNAs in the TCGA-LIHC data set. A prognostic model was constructed with nine cuproptosis-related prognostic lncRNAs (AC007998.3, AC003086.1, AC009974.2, IQCH-AS1, LINC0256 1, AC105345.1, ZFPM2-AS1, AL353708.1 and WAC-AS1) using LASSO regression and Cox regression analyses. Risk scores were calculated for all HCC patient samples based on the four cuproptosis-related lncRNA prognostic models. All HCC patients were divided into high-risk and low-risk subgroups according to a 1:1 ratio column. The Kaplan-Meier survival curve analysis showed that the overall survival rate (OS) of the high-risk group patients was significantly lower than that of the low-risk group. The principal component analysis (PCA) confirmed that the prognostic lncRNA model accurately distinguished between high- and low-risk HCC patients. Furthermore, regression analysis as well as ROC curves confirmed the prognostic value of the risk score. A nomogram with risk scores and other clinicopathological characteristics was constructed. The nomogram accurately predicted the probability of 1-, 3-, and 5-year OS in HCC patients. Tumor mutation burden (TMB) scores were higher for high-risk patients than for low-risk patients. HCC patients in the low-risk group showed lower TIDE scores and greater sensitivity to antitumor drugs than those in the high-risk group. Tumor immune responses and tumor immune cell infiltration were significantly different between the high-risk and low-risk groups of patients with HCC. Our study identified a 9-cuproptosis-related lncRNA signature that accurately predicted prognosis, immunotherapeutic efficacy, and the status of the tumor immune microenvironment in HCC patients. Therefore, this cuproptosis-related lncRNA risk model is a potential prognostic biometric feature in HCC and shows high clinical value in identifying HCC patients who are potentially responsive to immunotherapy.

Endofungal Bacterial Microbiota Promotes the Absorption of Chelated Inorganic Phosphorus by Host Pine through the Ectomycorrhizal System.

Ectomycorrhizal fungi play an irreplaceable role in phosphorus cycling. However, ectomycorrhizal fungi have a limited ability to dissolve chelated inorganic phosphorus, which is the main component of soil phosphorus. Endofungal bacteria in ectomycorrhizal fruiting bodies are always closely related to the ecological function of ectomycorrhizal fungi. In this study, we explore endofungal bacteria in the fruiting body of Tylopilus neofelleus and their function during the absorption of chelated inorganic phosphorus by host pine through the ectomycorrhizal system. The results showed that the endofungal bacterial microbiota in the fruiting body of T. neofelleus might be related to the dissolution of chelated inorganic phosphorus in soil. The soluble phosphorus content in the combined system of T. neofelleus and endofungal bacteria Bacillus sp. strain B5 was five times higher than the sum of T. neofelleus-only treatment and Bacillus sp. strain B5-only treatment in the dissolution experiment of chelated inorganic phosphorus. The results showed that T. neofelleus not only promoted the proliferation of Bacillus sp. strain B5 in the combined system but also improved the expression of genes related to organic acid metabolism, as assesed by transcriptomic analysis. Lactic acid content was five times higher in the combined system than the sum of T. neofelleus-only treatment and Bacillus sp. strain B5-only treatment. Two essential genes related to lactate metabolism of Bacillus sp. strain B5, gapA and pckA, were significantly upregulated. Finally, in a pot experiment, we verified that T. neofelleus and Bacillus sp. strain B5 could synergistically promote the absorption of chelated inorganic phosphorus by Pinus sylvestris in a ternary symbiotic system. IMPORTANCE Ectomycorrhizal fungi (ECMF) have a limited ability to dissolve chelated inorganic phosphorus, which is the main component of soil phosphorus. In the natural environment, the extraradical hyphae of ECMF alone may not satisfy the phosphorus demand of the plant ectomycorrhizal system. In this study, our results innovatively show that the ectomycorrhizal system might be a ternary symbiont in which ectomycorrhizal fungi might recruit endofungal bacteria that could synergistically promote the mineralization of chelated inorganic phosphorus, which ultimately promotes plant phosphorus absorption by the ectomycorrhizal system.

Nanogold sol plasmon discattering assay for trace carbendazim in tea coupled aptamer with Au3+-glyoxal-carbon dot nanocatalytic reaction.

Carbendazim (CBZ) is a broad-spectrum fungicide, which is toxic to mammals. Therefore, it is very necessary to establish a sensitive detection for food safety. An experiment found that CDFe exhibited excellent catalysis for the nano-indicator reaction of HAuCl4-glyoxal to produce gold nanoparticles (AuNPs) and that the generated AuNPs have a very strong surface-enhanced Raman scattering (SERS) effect at 1613 cm-1 in the presence of Victoria blue B molecular probes, and resonance Rayleigh scattering (RRS) signals at 370 nm. The aptamer (Apt) suppressed the catalysis of CDFe to cause the SERS and RRS signals decreasing. With the addition of CBZ, the specific Apt reaction occurred to restore the catalysis of CDFe, and resulting in a linear increase in the signals of RRS and SERS. As a result, this new nanocatalytic amplification indicator reaction was coupled with a specific Apt reaction of carbendazim (CBZ), to construct a new CDFe catalytic amplification-aptamer SERS/RRS discattering assay for ultratrace CBZ, which was used to analyze CBZ in tea samples with satisfactory results. In addition, this biosensoring platform can be also used to assay profenofos.

SERS- and absorbance-based catalytic assay for determination of isocarbophos using aptamer-modified FeMOF nanozyme and in situ generated silver nanoparticles.

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.

Ti3C2@Pd nanocatalytic amplification-polypeptide SERS/RRS/Abs trimode biosensoring platformfor ultratrace trinitrotoluene.

A new MXene supported Pd nanoparticles (Ti3C2@Pd) nanosol with good stability and strong catalysis was prepared by the two-step procedure. Experiment was found that Ti3C2@Pd could strongly catalyze the reduction of HAuCl4 by H2O2 to produce gold nanoparticles (AuNPs), with strong surface enhanced Raman scattering (SERS), resonance Rayleigh scattering (RRS) and surface plasmon resonance absorption (Abs). Coupled this new SERS/RRS/Abs trimode nanocatalytic indicator reaction with specific TNT polypeptide (PTTNT), a facile and selective trimode polypeptide biosensoring platform was established for the detection of ultratrace TNT, with a linear range of 1.1-66, 1.1-66 and 4.4-66 pmol/L TNT, and detection limit (DL) of 0.69, 0.97 and 3.36 pmol/L by SERS, RRS and Abs assay respectively. It has been used to detect TNT in wastewater and soil samples, with recovery of 98.7-106% and RSD of 6.22-8.77%. In addition, this biosensoring platform can be also used to assay glyphosate and estradiol, respectively.

A Simple and Sensitive Nanogold RRS/Abs Dimode Sensor for Trace As3+ Based on Aptamer Controlled Nitrogen Doped Carbon Dot Catalytic Amplification.

Using citric acid (CA) and ethylenediamine (EDA) as precursors, stable nitrogen-doped carbon dots (CD) nanosols were prepared by microwave procedure and characterized in detail. It was found that CDNs catalyze ethanol (Et)-HAuCl4 to generate gold nanoparticles (AuNPs), which have strong surface plasmon resonance, Rayleigh scattering, (RRS) and a surface plasmon resonance (SPR) absorption (Abs) effect at 370 nm and 575 nm, respectively. Compled the new catalytic amplification indicator reaction with the specific As3+ aptamer reaction, a new RRS/Abs dual-mode aptamer sensor for the assay of trace As3+ was developed, based on the RRS/Abs signals increasing linearly with As3+ increasing in the ranges of 5-250 nmol/L and 50-250 nmol/L, whose detection limits were 0.8 nmol/L and 3.4 nmol/L As3+, respectively. This analytical method has the advantages of high selectivity, simplicity, and rapidity, and it has been successfully applied to the detection of practical samples.

Effects of ectomycorrhizal fungus bolete identity on the community assemblages of endofungal bacteria.

Ectomycorrhiza-associated bacteria, especially endofungal bacterial microbiota (EBM) in the fruiting body, play important roles in driving the establishment and function of ectomycorrhizae. However, the influence of ectomycorrhizal fungus bolete identity on their EBM is still unclear. We analysed the EBM of three different bolete fruiting body species on Thousand Island Lake, including Tylopilus felleus, Tylopilus areolatus and Boletus queletii, and compared them with their corresponding mycosphere soil bacterial microbiota by high-throughput sequencing. The EBM was classified into Bacillus, Pseudomonas, Burkholderia and Stenotrophomonas genera. Proteobacteria, Bacteroidetes and Acidobacteria were predominant in the EBM of bolete fruiting bodies as well as their mycosphere soil, while Firmicutes was significantly higher in the EBM. Moreover, the core microbiome (342 operational taxonomic units) of the EBM was shared among the three bolete fungal species. The relative abundances of gene families related to cell cycle control and nucleotide, coenzyme and lipid metabolism were significantly higher in the EBM than in the corresponding mycosphere soil bacterial microbiota, but there was no difference among the three different boletes. The results suggested that the host identity of ectomycorrhizal fungus boletes could affect the EBM, which might be mainly due to the selection of host fungi for the different functional EBM needed.

Impact of RNA degradation on influenza diagnosis in the surveillance system.

BACKGROUND: The continuous evolution of influenza viruses is monitored by the World Health Organization Global Influenza Surveillance and Response System. Sample quality is essential for surveillance quality. METHODS: To evaluate the RNA degradation of clinical samples, influenza-like illness samples were collected from four sentinel hospitals, and seasonal influenza was tested by real-time reverse transcription polymerase chain reaction and quantified by digital reverse transcription polymerase chain reaction at different time points. RESULTS: RNA degradation was observed in the majority of samples eight days after sample collection. A significant and faster rate of RNA content reduction was observed in low viral load samples (<10 copies/µl) than in high viral load samples (>10 copies/µl), stored at 2 to 8°C for up to eight days. RNase P (RNP) RNA, which is a key indicator to evaluate sample collection quality, was detected. Sample collection quality was uneven in different hospitals. CONCLUSION: Low viral load samples increase the risk of false negatives due to RNA degradation to undetectable levels.

Effects of multi-phase inoculation on the fungal community related with the improvement of medicinal herbal residues composting.

Composting has become the most important way to recycle medicinal herbal residues (MHRs). The traditional composting method, adding a microbial agent at one time, has been greatly limited due to its low composting efficiency, mutual influence of microbial agents, and unstable compost products. This study was conducted to assess the effect of multi-phase inoculation on the lignocellulose degradation, enzyme activities, and fungal community during MHRs composting. The results showed that multi-phase inoculation treatment had the highest thermophilic temperature (68.2 °C) and germination index (102.68%), significantly improved available phosphorus content, humic acid, and humic substances concentration, accelerated the degradation of cellulose and lignin, and increased the activities of cellulase in the mature phase, xylanase, manganese peroxidase, and utilization of phenolic compounds. Furthermore, the non-metric multi-dimensional scaling showed that the composting process and inoculation significantly influenced fungal community composition. In multi-phase inoculation treatment, Thermomyces in mesophilic, thermophilic, and mature phase, unclassified_Sordariales, and Coprinopsis in mature phase were the dominant genus that might be the main functional groups to degrade lignocellulose and improve the MHRs composting process.

Endophytic bacteria promote the quality of Lyophyllum decastes by improving non-volatile taste components of mycelia.

Endophytic bacteria are always related to the host different traits, including the secondary metabolites production. However, the effect and mechanism of endophytic bacteria in the mushrooms fruit body on mycelia are still not clear. In this study, we investigated the effect of endophytic bacterial metabolites on the quality of Lyophyllum decastes mycelia. Soluble sugars, starch, protein, free amino acids, 5'-Nucleotides, EUC, and organic acids contents of mycelia were analyzed. We found that endophytic bacterial metabolites significantly increased the contents of soluble sugars, starch, protein, free amino acids, organic acids, and EUC. The present study thus suggests that endophytic bacteria could promote the quality of Lyophyllum decastes by improving non-volatile taste components of mycelia.

Preparation of AS1411 Aptamer Modified Mn-MoS2 QDs for Targeted MR Imaging and Fluorescence Labelling of Renal Cell Carcinoma.

BACKGROUND: Early diagnosis of renal cell carcinoma is extremely significant for the effective treatment of kidney cancer. The development of AS1411 aptamer modified Mn-MoS2 QDs provides a promising fluorescence/magnetic resonance (MR) dual-modal imaging probe for the precise diagnosis of renal clear cell carcinoma. METHODS: In this work, Mn-MoS2 QDs were synthesized through a simple "bottom-up" one-step hydrothermal method. AS1411 aptamer was modified on the Mn-MoS2 QDs to improve the specificity to renal cell carcinoma. The characteristics of Mn-MoS2 QDs were confirmed by transmission electronic microscopy (TEM), atomic force microscope (AFM), X-ray photoelectron spectrometer (XPS), photoluminescence (PL) emission spectra, etc. Cellular fluorescence labelling was investigated using the Mn-MoS2 QDs and AS1411-Mn-MoS2 QDs. The T1-weighted MR imaging was assessed by the in vitro MR cell imaging and in vivo MR imaging. Finally, the long-term toxicity of Mn-MoS2 QDs was investigated by the hematology and histological analysis. RESULTS: The prepared Mn-MoS2 QDs exhibited excellent aqueous property, intense fluorescence, low toxicity, high quantum yield of 41.45% and high T1 relaxivity of 16.95 mM-1s-1. After conjugated with AS1411 aptamer, the AS1411-Mn-MoS2 QDs could specifically fluorescently label the renal carcinoma cells and present a specific MRI signal enhancement in the tumor region of mice bearing renal carcinoma tumors. Furthermore, Mn-MoS2 QDs revealed low toxicity to the mice via hematology and histological analysis. CONCLUSION: These results demonstrated the potential of AS1411-Mn-MoS2 QD as a novel nanoprobe for targeted MR imaging and fluorescence labelling of renal cell carcinoma.

Genome-wide identification of interferon-sensitive mutations enables influenza vaccine design.

In conventional attenuated viral vaccines, immunogenicity is often suboptimal. Here we present a systematic approach for vaccine development that eliminates interferon (IFN)-modulating functions genome-wide while maintaining virus replication fitness. We applied a quantitative high-throughput genomics system to influenza A virus that simultaneously measured the replication fitness and IFN sensitivity of mutations across the entire genome. By incorporating eight IFN-sensitive mutations, we generated a hyper-interferon-sensitive (HIS) virus as a vaccine candidate. HIS virus is highly attenuated in IFN-competent hosts but able to induce transient IFN responses, elicits robust humoral and cellular immune responses, and provides protection against homologous and heterologous viral challenges. Our approach, which attenuates the virus and promotes immune responses concurrently, is broadly applicable for vaccine development against other pathogens.

Effect of transcutaneous electrical nerve stimulation therapy for the treatment of primary dysmenorrheal.

BACKGROUND: This study aimed to investigate the effect and safety of transcutaneous electrical nerve stimulation (TENS) therapy for relieving pain in women with primary dysmenorrhea (PD). METHODS: In this study, 134 participants with PD were randomly divided into the intervention group and the sham group, with 67 participants in each group. Participants in the intervention group received TENS, whereas those in the sham group received sham TENS. The primary outcome was measured by the Numeric Rating Scale (NRS). The secondary outcomes were measured by the duration of relief from dysmenorrheal pain, number of ibuprofen tablets taken, and the World Health Organization quality of life (WHOQOL)-BREF score, as well as the adverse events. RESULTS: A total of 122 participants completed the study. Compared to sham TENS, TENS showed a greater effect in pain relief with regard to the NRS (P < .01), duration of relief from dysmenorrheal pain (P < .01), and number of ibuprofen tablets taken (P < .01). However, no significant differences in the quality of life, measured by the WHOQOL-BREF score, were found between 2 groups. The adverse event profiles were also similar between 2 groups. CONCLUSION: TENS was efficacious and safe in relieving pain in participants with PD.

Genetic variation and geographic differentiation among populations of the nonmigratory agricultural pest Oedaleus infernalis (Orthoptera: Acridoidea) in China.

The nonmigratory grasshopper Oedaleus infernalis Saussure (Orthoptera : Acridoidea) is an agricultural pest to crops and forage grasses over a wide natural geographical distribution in China. The genetic diversity and genetic variation among 10 geographically separated populations of O. infernalis was assessed using polymerase chain reaction-based molecular markers, including the intersimple sequence repeat and mitochondrial cytochrome oxidase sequences. A high level of genetic diversity was detected among these populations from the intersimple sequence repeat (H: 0.2628, I: 0.4129, Hs: 0.2130) and cytochrome oxidase analyses (Hd: 0.653). There was no obvious geographical structure based on an unweighted pair group method analysis and median-joining network. The values of FST, θ(II), and Gst estimated in this study are low, and the gene flow is high (Nm > 4). Analysis of the molecular variance suggested that most of the genetic variation occurs within populations, whereas only a small variation takes place between populations. No significant correlation was found between the genetic distance and geographical distance. Overall, our results suggest that the geographical distance plays an unimpeded role in the gene flow among O. infernalis populations.

Colorimetric and ratiometric fluorescent detection of sulfite in water via cationic surfactant-promoted addition of sulfite to α,ß-unsaturated ketone.

Three fluorescent probes were constructed by incorporating an α,ß-unsaturated ketone to a coumarin fluorophore. The selective addition of sulfite to the alkene of TSP assisted by cetyltrimethyl ammonium bromide (CTAB) micelle can be visualized by dramatic color and ratiometric fluorescence changes. In CTAB-PBS system, the fluorescence intensity ratio at 465 nm and 592 nm (I465/I592) and the absorbance ratio at 390 nm and 470 nm (A390/A470) were linearly proportional to sulfite concentration in the range of 0.5-150 µM, and the detection limit was 0.2 µM. Good selectivity and competition of TSP1 towards sulfite over several anions and biological thiols were acquired. Probe TSP1 was used to detect sulfite in three realistic samples (mineral water, sugar and white wine) with good recovery.

Micelle-induced multiple performance improvement of fluorescent probes for H2S detection.

In this paper, two colorimetric and turn-on fluorescent probes N-[2-(2-hydroxy)-ethoxy] ethyl-4-azido-1,8-naphthalimide (SS1) and N-butyl-4-azido-1,8-naphthalimide (SS2) for selective recognition of H2S were designed and synthesized. The probes were constructed by incorporating an azido group into the naphthalimide fluorophore as a specifical reaction group for sulfide utilizing its reducing property. Once treated with H2S, the azido groups of the probes were converted to amino groups and the solutions' color changed from colorless to yellow companied with a strong yellow-green fluorescence. Rapid and sensitive responses of the probes towards H2S were achieved in the presence of cationic surfactant cetyltrimethyl ammonium bromide (CTAB): the reaction was completed within 10min in CTAB compared to more than 4h in buffer solution, and the detection limit decreased from 0.5µM to 20nM. High selectivity and good competition of both probes towards H2S over other 11 ions and 2 reducing agents were realized in CTAB micelle. An overall linear concentration range of 0.05µM to 1mM was achieved with the assistance of differently charged surfactants CTAB and sodium dodecyl sulfate (SDS). The probes were applied to rapidly and sensitively detect H2S levels in fetal bovine serum without any pretreatment of the sample.

[Rapid determination of benzene series in seawater by gas chromatography-mass spectrometry with static headspace extraction].

A method for the simultaneous determination of 13 benzene series (BTEX) in seawater using gas chromatography-mass spectrometry with static headspace extraction (HS-GC/MS) was developed. To carefully characterize the performance of this method, several factors affecting parameters were studied in detail, such as the type of column, heating procedure, equilibrium temperature, equilibrium time and the volume ratio of gas phase to liquid phase. The optimized conditions were as follows: the polar column of DB-WAX; heating procedure, 40 degrees C kept for 4 min, then raised to 120 degrees C at 10 degrees C/min, to 180 degrees C at 25 degrees C/min; equilibrium temperature, 80 degrees C; equilibrium time, 10 min; and the volume ratio of gas phase to liquid phase, 1:1. Under the optimized conditions, the linear equations were obtained in the concentration range of 0.16-320 microg/L with correlation coefficients greater than 0.999. The limits of detection (S/N = 3) were 0.019-0.033 microg/L. The recoveries at the three spiked levels of 1.6, 16 and 160 microg/L ranged from 81. 25% to 103.73% with the relative standard deviations (RSD, n=6) from 0.3% to 4.4%. The analytical results of the practical seawater samples from Shanghai Huangpu District were satisfactory. The determination of the 13 benzene series can be finished in 12 min. The method is simple, accurate, reliable, efficient and environmental-friendly.

A nonenzymatic cholesterol sensor constructed by using porous tubular silver nanoparticles.

Porous tubular silver (Ag) nanoparticles were successfully synthesized by electrodeposition of Ag into cadmium sulfide (CdS) modified porous anodic alumina (PAA) template and removal of CdS subsequently. Only the solid nanorods were obtained without CdS. The strong affinity between S2- and Ag (I) caused preferential deposition of Ag on the pore walls to form tubular Ag. After removal of CdS, porous tubular Ag nanoparticles were obtained. This novel nanostructure was characterized by XRD, TEM, FESEM, EDS and nitrogen adsorption-desorption isotherms. Using porous tubular Ag nanoparticles modified glassy carbon electrode (GCE) as a working electrode, a good nonenzymatic cholesterol sensor was constructed, which showed markedly improved electrocatalytic activity toward cholesterol oxidation compared to that of solid Ag nanorods. Under optimal detection conditions, the constructed sensor had a linear response range of 2.8 x 10(-4) M to 3.3 x 10(-2) M and the detection limit was 1.8 x 10(-4) M at a signal-to-noise ratio of 3. The biosensor showed an acceptable reproducibility, good stability and low interferences. To the best of our knowledge, it is the first example of a nonenzymatic cholesterol biosensor based on Ag nanoparticles. The experimental results demonstrated that porous tubular Ag nanoparticles provided a promising platform for rational design and fabrication of nonenzymatic cholesterol sensors.

Facile synthesis of porous tubular palladium nanostructures and their application in a nonenzymatic glucose sensor.

Porous tubular palladium nanostructures were synthesized by electrodeposition of palladium into a CdS modified alumina template and subsequent removal of CdS; the nanostructures provided a promising platform for the fabrication of nonenzymatic glucose sensors.