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Introduction: Pseudorabies (PR) is a multi-animal comorbid disease caused by pseudorabies virus (PRV), which are naturally found in pigs. At the end of 2011, the emergence of PRV variant strains in many provinces in China had caused huge economic losses to pig farms. Rapid detection diagnosis of pigs infected with the PRV variant helps prevent outbreaks of PR. The immunochromatography test strip with colloidal gold nanoparticles is often used in clinical testing due to its low cost and high throughput. Methods: This study was designed to produce monoclonal antibodies targeting PRV through immunization ofmice using the eukaryotic systemto express the gE glycoprotein. Subsequently, paired monoclonal antibodies were screened based on their sensitivity and specificity for use in the preparation of test strips. Results and discussion: The strip prepared in this study was highly specific, only PRV was detected, and there was no cross-reactivity with glycoprotein gB, glycoprotein gC, glycoprotein gD, and glycoprotein gE of herpes simplex virus and varicellazoster virus, porcine epidemic diarrhea virus, Senecavirus A, classical swine fever virus, porcine reproductive and respiratory syndrome virus, and porcine parvovirus. Moreover, it demonstrated high sensitivity with a detection limit of 1.336×103 copies/µL (the number of viral genome copies permicroliter); the coincidence rate with the RT-PCR detection method was 96.4%. The strip developed by our laboratory provides an effective method for monitoring PRV infection and controlling of PR vaccine quality. [ABSTRACT FROM AUTHOR]

Avian leukemia is an infectious tumorous disease of chickens caused by subgroup A of the avian leukemia virus (ALV-A), which mainly causes long-term viremia, slow growth, immune suppression, decreased production performance, multi-tissue tumors, and even death. The infection rate of this disease is very high in chicken herds in China, causing huge economic losses to the poultry industry every year. We successfully expressed the specific antigen protein of ALV (P27) through recombinant protein technology and screened a pair of highly sensitive monoclonal antibodies (mAbs) through mouse immunity, cell fusion, and antibody pairing. Based on this pair of antibodies, we established a dual antibody sandwich ELISA and gold nanoparticle immunochromatographic strip (AuNP-ICS) detection method. In addition, the parameters of the dual antibody sandwich ELISA and AuNP-ICS were optimized under different reaction conditions, which resulted in the minimum detection limits of 0.2 ng mL−1 and 1.53 ng ml−1, respectively. Commonly available ELISA and AuNP-ICS products on the market were compared, and we found that our established immune rapid chromatography had higher sensitivity. This established AuNP-ICS had no cross-reactivity with Influenza A (H1N1), Influenza A (H9N2), respiratory syncytial virus (RSV), varicella-zoster virus (VZV), Listeria monocytogenes listeriolysin (LLO), and Staphylococcal enterotoxin SED or SEC. Finally, the established AuNP-ICS was used to analyze 35 egg samples, and the results showed 5 positive samples and 30 negative samples. The AuNP-ICS rapid detection method established by our group had good specificity, high sensitivity, and convenience, and could be applied to the clinical sample detection of ALV-A. [ABSTRACT FROM AUTHOR]

Gold in Carlin-type gold ores is commonly hosted in the arsenian pyrite rim, but the formation of arsenian pyrite and its contribution to Au adsorption are poorly understood. Based on our previous NanoSIMS Au mapping, we conducted SEM and HR-TEM analyses to examine the Au deportment and nanoscale texture of individual auriferous arsenian pyrite grains from the giant Carlin-type Lannigou gold deposit, SW China. The results indicate that the arsenian pyrite rim is composed of numerous nanoparticulate pyrite grains (rather than a single crystal), and gold nanoparticles (Au0) occur mainly in sub-rim with the highest Au content, which are porous and have lower degrees of order. We propose that nanoparticulate arsenian pyrite attachment and aggregation is the main mechanism for the arsenian pyrite rim growth, and such mechanism is crucial for the Au efficient enrichment for this giant gold deposit. [ABSTRACT FROM AUTHOR]

Raman spectroscopy exhibits potential as a tool for identifying the chemical composition of substances and has witnessed a growing application in urological oncology. This study undertook a bibliometric analysis to chart the present state and future prospects of Raman spectroscopy applications in urological tumors. The present study retrieved literature on the utilization of Raman spectroscopy in urological oncology from the Science Citation Index Expanded of Web of Science Core Collection, spanning from its inception to June 2023. Data from included studies were analyzed using CiteSpace, Python, and Excel. Our study examined 897 articles from 65 countries and identified a significant exponential growth in annual publications. The USA and China were prominent contributors to this field, with high publication rates and funding agencies. Shanghai Jiao Tong University emerged as the most influential institution. The journals Analytical Chemistry and Analyst were found to be the most productive. Our keyword analysis revealed an intense interest for "gold nanoparticle" and "pathology," with the most recent bursts occurring for "surface-enhanced Raman scattering (SERS)," "biomarkers," and "prostate specific antigen." As a detection tool, Raman spectroscopy holds the potential to assist in the identification, management, and prognostication of urological tumors. Notably, adjuvant diagnosis and prognosis evaluation based on SERS of tumor markers is a hot research topic. These findings offer valuable insights into the current state of Raman spectroscopy research in urological oncology, which could inform future studies and clinical practice. [ABSTRACT FROM AUTHOR]

Cervical cancer is an important topic in the study of global health issues, ranking fourth among women's cancer cases in the world. It is one of the nine major cancers that China is focusing on preventing and treating, and it is the only cancer that can be prevented through vaccination. Systematic and effective screening for human papilloma (HPV) infection, which is closely linked to the development of cervical cancer, can reduce cervical cancer incidence and mortality. In this paper, an electrochemical sensor was designed to detect HPV 16 using dual-signal amplification. An APTES-modified glassy carbon electrode was used for improved stability. Gold nanoparticles and a chain amplification reaction were combined for signal amplification. The limit of detection (LOD) of this electrochemical sensor was 1.731 × 10−16 mol/L, and the linear response of the target detector range was from 1.0 × 10−13 mol/L to 1.0 × 10−5 mol/L (R2 = 0.99232). The test of serum sample recovery showed that it has good anti-interference, and the performance of all aspects was improved to different degrees compared with the previous research from the team. The designed sensor is centered around the principles of low cost, high sensitivity and stability, which provides new ideas for the future development of cervical cancer prevention and electrochemical biosensors. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths in China. Glypican-3 (GPC3) is a specific antigen related to HCC, which is widely used in clinical detection as a reliable marker of HCC. In this paper, a highly sensitive homogeneous apatasensor was designed for GPC3 detection based on fluorescence resonance energy transfer (FRET) where the GPC3 aptamer labelled gold carbon dots (AuCDs-GPC3Apt) are used as a donor and magnetic graphene oxide (Fe3O4/GO) nanosheets are used as an acceptor. A one-step hydrothermal method was used to synthesize AuCDs to provide sufficient fluorescence. The FRET phenomenon exists between AuCDs-GPC3Apt and Fe3O4/GO, which weakens the fluorescence intensity of the whole system. When the target GPC3 is added to the FRET system, the fluorescent AuCDs-GPC3Apt binds to the GPC3 and forms a folded structure, which leads to AuCDs-GPC3Apt separation from Fe3O4/GO nanosheets. The Fe3O4/GO is then magnetically separated so that the fluorescence of free labelled AuCDs-GPC3Apt is restored. Under the optimum conditions, the fluorescence recovery rate is linearly correlated with the concentration of GPC3 (5–100 ng·mL−1) and the detection limit is 3.01 ng·mL−1 (S/N = 3). This strategy shows recoveries from 98.76 to 101.29% in real human serum samples and provides an immediate and effective detection method for the quantification of GPC3 with great potential applications for early diagnosis of HCC. A sensitive homogeneous FRET-based apatasensor was designed for GPC3 detection where the AuCDs-GPC3Apt is a donor and Fe3O4/GO nanosheets are an acceptor. The GPC3 fluorescent aptasensor combines wider output range with low cost, high specificity, and good anti-interference. [ABSTRACT FROM AUTHOR]

The sensitive and stable detection of trace heavy metals in liquid is crucial given its profound impact on various aspects of human life. Currently, nanoparticle-enhanced laser-induced breakdown spectroscopy (NELIBS) with dried droplet method (DDM) is widely applied for heavy metals detection. Nevertheless, the coffee ring effect (CRE) in DDM affects the stability, accuracy, and sensitivity of NELIBS. Here, we developed a slippery surface-aggregated substrate (SS substrate) to suppress the CRE and enrich analytes, and form a plasmonic platform for NELIBS detection. The SS substrate was prepared by infiltrating perfluorinated lubricant into the pores of PTFE membrane. The droplet, with targeted elements and gold nanoparticles, was dried on the SS substate to form the plasmonic platform for NELIBS analysis. Then, trace heavy metal elements copper (Cu) and manganese (Mn) were analyzed by NELIBS. The results of Cu (RSD = 5.60%, LoD = 3.72 μg/L) and Mn (RSD = 7.42%, LoD = 6.37 μg/L), illustrated the CRE suppression and analytes enrichment by the SS substrate. The results verified the realization of stable, accurate and sensitive NELIBS detection. And the LoDs succeeded to reach the standard limit of China (GB/T 14848-2017). Furthermore, the results for groundwater detection (relative error: 5.92% (Cu) and 4.74% (Mn)), comparing NELIBS and inductively coupled plasma mass spectrometry (ICP-MS), validated the feasibility of the SS substrate in practical applications. In summary, the SS substrate exhibits immense potential for practical application such as water quality detection and supervision. [Display omitted] • A slippery surface-aggregated substrate in dried droplet method (DDM). • Suppression of coffee ring effect and enrichment of analytes by slippery surface-aggregated substrate. • Good performance in the detection of practical groundwater with stable, accuracy, and ultrasensitive analysis using NELIBS. [ABSTRACT FROM AUTHOR]

Fupenzi (Rubus chingii Hu) is a dried and immature fruit in East China, which has effects of nourishing kidneys, solidifying essence, and otherwise. Because Fupenzi was often adulterated and replaced with inferior things, this paper had researched Fupenzi and its adulterant raspberry. A new type of visible sensor was constructed by using Au nanoparticles (AuNPs), which was modified by the surface-active agent and combined with the ultraviolet-visible (UV-vis) spectrum technology. It was found that the change in particle size after the interaction of AuNPs and adulterants will lead to color change. In this paper, the RGB (red, green, and blue) values of the solution were extracted to correlate the color with the concentration of adulterants, and the relationship between the absorption peak intensity and the concentration of adulterants was established. The results showed that the intensity of an absorption peak is related to adulteration concentration, and the color of the solution changed from red to gray as the particle size changed. The visual sensor constructed based on the above principle is a fast and precise method to detect adulteration with different concentrations, which has a potential application value in real-time and rapid detection of Fupenzi's quality. [ABSTRACT FROM AUTHOR]

In recent years, the morbidity and mortality of gastrointestinal cancer have remained high in China. Due to the deep location of the gastrointestinal organs, such as gastric cancer, the early symptoms of cancer are not obvious. It is generally discovered at an advanced stage with distant metastasis and lymph node infiltration, making it difficult to cure. Therefore, there is a significant need for novel technologies that can effectively diagnose and treat gastrointestinal cancer, ultimately reducing its mortality. Gold nanoparticles (GNPs), a type of nanocarrier with unique optical properties and remarkable biocompatibility, have the potential to influence the fate of cancer by delivering drugs, nucleic acids to cancer cells and tissues. As a safe and reliable visualization agent, GNPs can track drugs and accurately indicate the location and boundaries of cancer, opening up new possibilities for cancer treatment. In addition, GNPs have been used in photodynamic therapy to deliver photosensitizers, as well as in combination with photothermal therapy. Therefore, GNPs can be used as a safe and effective nanomaterial in the treatment and diagnosis of gastrointestinal cancer. [ABSTRACT FROM AUTHOR]

Biosensors with nanomaterials and enzymes detect and quantify specific targets in samples, converting recognition into measurable signals. The study explores the intrinsic synergy between these elements for detecting and quantifying particular targets in biological and environmental samples, with results demonstrated through bibliometric analysis and a comprehensive review of enzyme-based biosensors. Using WoS, 57,331 articles were analyzed and refined to 880. Key journals, countries, institutions, and relevant authors were identified. The main areas highlighted the multidisciplinary nature of the field, and critical keywords identified five thematic clusters, revealing the primary nanoparticles used (CNTs, graphene, AuNPs), major application fields, basic application themes, and niche topics such as sensitive detection, peroxidase activity, and quantum dot utilization. The biosensor overview covered nanomaterials and their primary applications, addressing recent advances and inherent challenges. Patent analysis emphasized the U.S. leadership in the industrial sector, contrasting with China's academic prominence. Future studies should focus on enhancing biosensor portability and analysis speed, with challenges encompassing efficient integration with recent technologies and improving stability and reproducibility in the nanomaterial-enzyme interaction. [Display omitted] • The review assessed nanomaterials' role in advancing biosensors with enzymes. • 57,331 docs explored nanomaterials' enzyme-based biosensor use. • Outlined top journals, nations, authors, and key papers • The 20 main keywords allow the formation of 4 clusters. • Comprehensive guidelines are provided for biosensor research. [ABSTRACT FROM AUTHOR]

Salmonella is a prevalent pathogen causing serious morbidity and mortality worldwide. There are over 2600 serovars of Salmonella. Among them, Salmonella Enteritidis, Salmonella Typhimurium, and Salmonella Paratyphi were reported to be the most common foodborne pathogenic serovars in the EU and China. In order to provide a more efficient approach to detect and distinguish these serovars, a new analytical method was developed by combining surface-enhanced Raman spectroscopy (SERS) with multi-scale convolutional neural network (CNN). We prepared 34-nm gold nanoparticles (AuNPs) as the label-free Raman substrate, measured 1854 SERS spectra of these three Salmonella serovars, and then proposed a multi-scale CNN model with three parallel CNNs to achieve multi-dimensional extraction of SERS spectral features. We observed the impact of the number of iterations and training samples on the recognition accuracy by changing the ratio of the number of the training and testing sets. By comparing the calculated data with experimental one, it was shown that our model could reach recognition accuracy more than 97%. These results indicate that it was not only feasible to combine SERS spectroscopy with multi-scale CNN for Salmonella serotype identification, but also for other pathogen species and serovar identifications. [ABSTRACT FROM AUTHOR]

Recent studies have identified gold nanoparticles in ores in a range of deposit types, but little is known about their formation processes. In this contribution, gold-bearing magnetite from the well-documented, world-class Beiya Au deposit, China, was investigated in terms of microstructure and crystallography at the nanoscale. We present the first three-dimensional (3D) focused ion beam/scanning electron microscopy (FIB/SEM) tomography of the distribution of gold nanoparticles in nanopores in the low-Si magnetite. The porous low-Si magnetite, which overprints an earlier generation of silician magnetite, was formed by a coupled dissolution-reprecipitation reaction (CDRR). The extrinsic changes in thermodynamic conditions (e.g., S content and temperature) of the hydrothermal fluids resulted in the CDRR in magnetite and the disequilibrium of Au-Bi melts. The gold nanoparticles crystallized from Au-supersaturated fluids originating from the disequilibrium of Au-Bi melts and grew in two ways depending on the intrinsic crystal structure and pore textures: (1) heteroepitaxial growth utilizing the (111) lattice planes of magnetite, and (2) randomly oriented nucleation and growth. Therefore, this study unravels how intrinsic and extrinsic factors drove the formation of gold nanoparticles at fluid-mineral interfaces. [ABSTRACT FROM AUTHOR]

Electrochemiluminescence biosensor is an analytical method combining electrochemiluminescence technology with biosensor. Using nanomaterials as electrochemical luminescence sensor platform can not only immobilize a large number of biomolecules but also improve the performance of the sensor to realize the supersensitive detection of biomacromolecules. Although these methods have high sensitivity for bioanalysis, there are still some shortcomings which limit the practical application. Therefore, this paper discusses the development of functional gold nanomaterials industry and its application in chemiluminescence bioanalysis. In this paper, two methods of synthesizing luminescent functional gold nanomaterials at room temperature were studied by using chemiluminescent reagents as reducing agent and protective agent. Based on luminescent functionalized gold nanoparticles, immunoassay and DNA bioanalysis probes were constructed, and their applications in chemiluminescence and electrochemiluminescence bioanalysis were discussed. Finally, the simulation results show that the relative deviation between the experimental results and the existing clinical methods is less than 17%. The sensor has good stability and selectivity and can be used for the determination of CEA in human serum. The gold nanomaterials synthesized by further research have excellent chemiluminescence activity and can be used to label biomolecules and prepare biological probes. This article aims to explore the application of chemical methods in the transformation of new industries, to achieve breakthroughs in new products in industrial innovation, and to achieve the cross-fusion of management science and engineering disciplines and chemical disciplines. The industrial development of derivative functionalized gold nanomaterials has broad application prospects in biological analysis. [ABSTRACT FROM AUTHOR]

The Shuiyindong Carlin-like gold deposit, the largest one of this type in China, is located in the Late Paleozoic–Early Mesozoic Youjiang basin. The pyrites in the studied ore bodies (No. I to V) can be divided into four main types plus several sub-types: (1) As-poor pyrites include Py1 (Py1a and Py1b), Py2, and Py3; and (2) As-rich pyrite Py4 (Py4a and Py4b). In situ LA-ICP-MS analyses show that the As-rich pyrite also contains higher Au, Cu, Sb, and Tl than the other pyrite types. In situ NanoSIMS analyses show the δ34S variation of Py1 (48.1~67.5‰), Py2 (2.4~7.6‰), Py3 (9.2~14.2‰), and Py4 (− 3.0~6.6‰), with the average values of 58.1‰, 5.1‰, 11.4‰, and 3.1‰, respectively. The large δ34S variations of As-poor pyrites may reflect a sedimentary source. However, the narrow ranges of δ34S values for the As-rich pyrite (Py4) may not reflect a sedimentary but a magmatic or metamorphic origin. A metamorphic sulfur source of Py4 is favored due to paucity of coeval magmatism in the region and decreasing variations of δ34S values from Py1 to Py4. Integrated transmission electron microscope (TEM) and NanoSIMS element mapping show that the distribution and concentration of Au are discordant with As and Cu at the submicron scale, also implied by the occurrence of some of Au as nano-submicron particles in Py4. Overall, our new data indicate that the ore fluids were not only enriched in Au but also in As, Cu, and S. Taking an alternative of fluid oxidation probably resulting in the decreasing δ34S values of Py4, our result of I to V orebodies indicates the mixing between the underlying metamorphic fluid and meteoric water. Integrated variations in δ34S and As-Au-Cu correlations across individual pyrite grains infer the physicochemical changes of aqueous and/or aqueous-carbonic fluids along migration paths. [ABSTRACT FROM AUTHOR]

DNA-functionalized Au nanoparticles (AuNPs) have been intensively exploited as programmable atom equivalents (PAEs) for the self-assembly of molecule-like structures. However, it remains challenging to build hierarchical PAE assemblies via discrete DNA bonds at different levels. Here, we report a strategy to program DNA bond length and bond energy on PAEs using DNA encoders carrying consecutive adenines (polyA). On AuNPs, we built three types of DNA motifs with different topologic configurations, which can form bonds for PAE self-assembly. By small-angle X-ray scattering (SAXS) analysis, we found that the bond length and flexibility between the coupled PAEs can be tuned by programming the bond structure. We also found that these bonds show different bond energies and thus differ, depending on their topologic configuration, leading to different PAE assembly efficiencies. We demonstrated that the bonds at different levels can be arranged in different directions on one nanoparticle, leading to asymmetric PAEs that allow ionic strength-controlled hierarchical assembly of multiparticle structures. This programmable bonding system may provide a new route for building complex plasmonic superstructures. Nanoparticle assembly: Organization by DNA Using different DNA structures can control how gold nanoparticles organize themselves according to researchers in China. Dictating the way nanoparticles aggregate when mixed is important for reproducibly controlling the properties of the resulting material. One way to achieve this is to coat the nanoparticles with DNA: DNA base-pairing allows for easily controlled assembly and enables the nanoparticles to organize themselves into a repeating pattern. This lattice structure is similar to that formed by atoms in solids, and so these DNA- coated particles are often referred to as "programmable atom equivalents" (PAEs). Jiang Li from the Shanghai Advanced Research Institute and co-workers investigated three types of DNA with different recurring patterns on gold nanoparticles. They showed that the different patterns created different bond lengths, leading to different PAE assembly efficiency. In this work, we report a strategy to build programmable atom equivalents (PAEs) with tailorable DNA bond length and bond energy using DNA encoders carrying consecutive adenines (polyA). We find that the bond length and bond energy can be tuned by programming the topologic configurations of the DNA encoders, which lead to differently leveled bonds and asymmetric PAEs allowing for directional, hierarchical assembly of multi-particle structures. This programmable bonding system may provide a new route for building complex plasmonic superstructures. [ABSTRACT FROM AUTHOR]

The highly heavy metal resistant strain Cupriavidus metallidurans BS1 was isolated from the Zijin gold–copper mine in China. This was of particular interest since the extensively studied, closely related strain, C. metallidurans CH34 was shown to not be only highly heavy metal resistant but also able to reduce metal complexes and biomineralizing them into metallic nanoparticles including gold nanoparticles. After isolation, C. metallidurans BS1 was characterized and complete genome sequenced using PacBio and compared to CH34. Many heavy metal resistance determinants were identified and shown to have wide-ranging similarities to those of CH34. However, both BS1 and CH34 displayed extensive genome plasticity, probably responsible for significant differences between those strains. BS1 was shown to contain three prophages, not present in CH34, that appear intact and might be responsible for shifting major heavy metal resistance determinants from plasmid to chromid (CHR2) in C. metallidurans BS1. Surprisingly, the single plasmid – pBS1 (364.4 kbp) of BS1 contains only a single heavy metal resistance determinant, the czc determinant representing RND-type efflux system conferring resistance to cobalt, zinc and cadmium, shown here to be highly similar to that determinant located on pMOL30 in C. metallidurans CH34. However, in BS1 another homologous czc determinant was identified on the chromid, most similar to the czc determinant from pMOL30 in CH34. Other heavy metal resistance determinants such as cnr and chr determinants, located on megaplasmid pMOL28 in CH34, were shown to be adjacent to the czc determinant on chromid (CHR2) in BS1. Additionally, other heavy metal resistance determinants such as pbr , cop , sil , and ars were located on the chromid (CHR2) and not on pBS1 in BS1. A diverse range of genomic rearrangements occurred in this strain, isolated from a habitat of constant exposure to high concentrations of copper, gold and other heavy metals. In contrast, the megaplasmid in BS1 contains mostly genes encoding unknown functions, thus might be more of an evolutionary playground where useful genes could be acquired by horizontal gene transfer and possibly reshuffled to help C. metallidurans BS1 withstand the intense pressure of extreme concentrations of heavy metals in its environment. [ABSTRACT FROM AUTHOR]

The 13-km-long Sanshandao gold belt along the NNE-trending Sanshandao Fault has highly variable orogenic gold endowment along-strike. New thermochronological data from the small Cangshang gold deposit demonstrate similar degrees of uplift and exhumation rates as for larger deposits, negating selective preservation as the prime gold-endowment factor. The Haiyu, Sanshandao, Xiling, and Cangshang deposits, of variable gold endowment, lie adjacent to NE-ENE-trending jogs, similar to those at Jiaojia and Linglong, so these structures cannot be the prime control on gold mineralization. Ore-zones show a broad gentle northeast plunge, with the southwestern Cangshang and Xinli deposits being closest to the ground surface, and the northeastern Haiyu deposit being the deepest. Thus, preferential erosion of the shallower southwestern orebodies could be a factor affecting endowment. Another variable is the depth of drilling. At Haiyu-Sanshandao, gold mineralization is better developed on more gently dipping fault segments, consistent with a thrust component of oblique slip along them. Relative to the northeastern deposits, the Cangshang and Xinli deposits are located in areas where relatively shallow drilling has intersected ore zones on steeply dipping fault segments, indicating the potential for deeper drilling to intersect gold ore along deeper more gently dipping segments. Heterogeneous gold endowment is thus largely a formational factor related to the plunge of orebodies combined with the variable depth of drilling along the Sanshandao Fault. Over the entire Jiaodong gold province, there are equivalent-age mesozonal to epizonal orebodies, implicating their preservation at different crustal levels and thus increasing the province-scale gold endowment potential and probability of further exploration discoveries. [ABSTRACT FROM AUTHOR]

Fluorescence-based aptasensors possess high sensitivity but are complicated and usually require multistep labeling and modification in method design, which severely limit the practical applications. Here, a label-free fluorescence-based aptasensor, consisting of aptamer, gold nanoparticles (AuNPs), and cadmium telluride (CdTe) quantum dots (QDs), was developed for the detection of sulfadimethoxine (SDM) in water and fish based on the specific recognition of SDM-aptamer and the inner filter effect of QDs and AuNPs. In the absence of a target, AuNPs dispersed in salt solution because of the aptamer protection, which could effectively quench the fluorescence emission of QDs, while in the presence of SDM, AuNPs aggregated due to the specific recognition of SDM-aptamer to SDM, which resulted in fluorescence recovery. A linear response of SDM concentrations in the range of 10–250 ng mL−1 (R2 = 0.99) was obtained, and the detection limit was 1.54 ng mL−1 (3σ, n = 9), far below the maximum residue limit (100 ng mL−1) of SDM in edible animal tissues regulated by China and the European Commission. The fluorescence-based aptasensor was applied to the detection of SDM in aquaculture water and fish samples with high accuracy, excellent precision, and ideal selectivity. The results indicated that the developed aptasensor was simple in design, easy to operate, and could be used to detect rapidly and accurately SDM in water and fish samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • Gold occurs as visible natural Au and invisible nanoparticles in pyrite. • The ore-forming materials were mainly related to the Late Mesozoic granitic magmatism. • The Au mineralization in the Hongzhuang-Yuanling deposits is the distal product of the Shiyaogou porphyry system. The Hongzhuang and Yuanling gold deposits are located in the Shiyaogou ore field within the Xiong'ershan area, East Qinling, China, where the ore bodies are hosted in Xiong'er Group and mainly controlled by EW-trending and NE-trending faults. The gold mineralization mechanism and the possible genetic link with the porphyry magmatism and hydrothermal events remain unclear. Here we present results from systematic field investigation, petrographic observation, in situ trace elements and sulfur isotope of pyrite to elucidate the genesis of gold mineralization in these deposits. Based on the occurrences of pyrite in different hydrothermal veins, three types of pyrite are identified from each deposit, including: i) coarse-grained cubic pyrite (HZ-Py1 and YL-Py1) in stage I milky quartz vein; ii) medium- to fine-grained pyrite (HZ-Py2 and YL-Py2) in stage II polymetallic sulfides veins; iii) coarse-grained pyrite (HZ-Py3 and YL-Py3) symbiotic with calcite in stage III quartz-calcite vein. The LA-ICP-MS trace element analyses of pyrite show that Au occurs as invisible nanoparticles or nano-sized inclusions in pyrite through absorption-chemisorption during the growth of pyrite or as nano-sized Au-bearing mineral inclusions. The δ34S values of different generations of pyrite in the Hongzhuang and Yuanling gold deposits range from 3.92‰ to 6.43‰ and 2.82‰ to 4.46‰, respectively, indicating that the ore-forming materials were mainly derived from mantle-related source with affinity to the Late Mesozoic granitic magmatism. The Hongzhuang and Yuanling gold deposits are spatially and temporally correlated with the Shiyaogou pluton and they show consistent material sources. We propose that the hydrothermal Au mineralization in these deposits were the distal products generated from the post-magmatic fluids of the Shiyaogou porphyry system. The stretching and thinning of the early Cretaceous lithosphere led to the upwelling of magma and migration of fluid, forming the Au mineralization in fault structures in the shallow crust. [ABSTRACT FROM AUTHOR]

Fumonisin B1 (FB1) is one of the most toxic and widely distributed subtypes of the 20 fumonisins, which has attracted much attention in food and feed safety. In this study, a convenient colorimetric immunoassay was proposed for the detection of FB1 based on Mn2+-mediated aggregation of gold nanoparticles (AuNPs). After hydrolyzing of ascorbic acid 2-phosphate (AAP) by alkaline phosphatase (ALP), the generated ascorbic acid (AA) decomposes brown MnO 2 shell to Mn2+, which growth onto AuNPs and inducing the aggregation of AuNPs. The color change of the solution induced by aggregating of AuNPs can be read by smartphone to avoid subjective differences. The limit of detection (LOD) of this assay was 0.15 ng/mL and the limit of quantification (LOQ) was 0.50 ng/mL. The method has not cross-reaction with other mycotoxins. The average recoveries of FB1 in the maize flour samples ranged from 86.4 % to 110.9 %, which met the food and Drug Administration (FDA) restrictions on FBS in agricultural products. The colorimetric immunoassay can be potentially used for mycotoxin-related food safety monitoring. • A novel immunosensor for FB1 was developed based on Mn2+ mediated AuNPs aggregation. • With smartphone readings, precise on-site quantitative testing can be carried out without the need of other equipment. • The LOD is lower than maximum residue limit of FB1 set by China, EU, US and FAO. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanoparticles are divided into ANPs, A&C mixed NPs, and CNPs. • A&C mixed NPs are a newly proposed nanoparticle class. • Ore-related nanoparticles can predict concealed ore bodies. Surface nanoparticles in nature have become important research objects because they contain information about the deep Earth. In this study, nanoparticles were analyzed via Transmission Electron Microscopy (TEM) in gradient media (groundwater, ascending gas, and soil) on the surface overlying the concealed Shaling gold deposit in China, which was buried more than 1000 m below the surface. The morphologies, ultramicroscopic structure, and chemical composition of the nanoparticles were analyzed via High-Resolution TEM (HRTEM), Selected Area Electron Diffraction (SAED), and Energy Dispersive Spectroscopy (EDS). These nanoparticles were characterized as (i) Amorphous Nano-Particles (ANPs), (ii) Amorphous-and-Crystalline-mixed Nano-Particles (A&C mixed NPs), and (iii) Crystallized Nano-Particles (CNPs). Furthermore, the newly proposed A&C mixed NPs were further classified into wrapped-, adsorbed- and coexisting-type nanoparticles. The ANPs exhibited a disorderly arrangement, A&C mixed NPs comprised amorphous materials as well as crystalline grains, and CNPs predominantly consisted of crystallized bodies. Oxidized particles derived from concealed ore bodies contain ore-related information and migrate to the surface via the flow of groundwater and ascending gas along faults. Among these particles, amorphous-bearing nanoparticles can contain elements with similar geochemical behaviors, such as Ca and Zn. Overall, this study provides a new basis for the exploration of concealed ore bodies. [ABSTRACT FROM AUTHOR]

• A rapid immunochromatographic assay based on antibody colloidal gold nanoparticles specific to GoAstV was developed for the detection of GoAstV. • The immunochromatographic strip (ICS) assay was highly specific, sensitive, repeatable, and more rapidly detect GoAstV in clinical samples. • The novel goose Astrovirus (GoAstV) lead to a huge loss in the poultry industry, and early diagnosis is required to prevent the disease from spreading. The novel goose astrovirus (GoAstV) is an emerging pathogenic virus that has resulted in large economic losses to the goose-rearing industry in China since 2016. The novel goose astrovirus cause gout in goslings with a mortality rate of around 50 %. Therefore, an effective diagnostic approach to monitor the spread of GoAstV is necessary. Here, a novel diagnostic immunochromatographic strip (ICS) assay was developed to detect GoAstV. A rapid immunochromatographic assay based on antibody colloidal gold nanoparticles specific to GoAstV was developed for the detection of GoAstV in goose allantoic fluid and supernatant of tissue homogenate. Monoclonal antibodies (Mabs) were prepared using the hybridoma technology, and the polyclonal antibodies (Pabs) were generated by immunizing the rabbits with recombinant ORF2 protein. In addition, the colloidal gold was prepared by reducing gold salt with sodium citrate coupled with Mabs against GoAstV. The optimal concentrations of the coating antibody and the capture antibody were examined as 1.6 mg/mL and 6 μg/mL. The optimal pH of the colloidal gold labeling was pH 8.0. With the visual observation, the lower limit of the ICS was reported to be approximately 1.2 μg/mL. Common diseases of goose were examined to assess the specificity of the ICS, and no cross-reaction was identified. 40 clinical positive samples were simultaneously detected by using the ICS and the PCR with a 92.5% coincidence rate between them. Furthermore, the mentioned samples could be stored at 25 °C and 4 °C for 4 and 6 months, respectively. It was proved that the ICS in this study was highly specific, sensitive, repeatable and more convenient to rapidly detect GoAstV in clinical samples. [ABSTRACT FROM AUTHOR]

Since emerging in China in December 2019, COVID-19 has spread globally, wreaked havoc for public health and economies worldwide and, given the high infectivity and unexpectedly rapid spread of the virus responsible—that is, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)—urged the World Health Organization to declare it a pandemic. In response, reducing the virus's adverse effects requires developing methods of early diagnosis that are reliable, are inexpensive and offer rapid response. As demonstrated in this article, the colorimetric and electrochemical detection of SARS-CoV-2 spike antigen with gold nanoparticle-based biosensors may be one such method. In the presence of the SARS-CoV-2 spike antigen, gold nanoparticles aggregated rapidly and irreversibly due to antibody–antigen interaction and consequently changed in colour from red to purple, as easily observable with the naked eye or UV–Vis spectrometry by way of spectral redshifting with a detection limit of 48 ng/mL. Moreover, electrochemical detection was achieved by dropping developed probe solution onto the commercially available and disposable screen-printed gold electrode without requiring any electrode preparation and modification. The method identified 1 pg/mL of the SARS-CoV-2 spike antigen and showed a linear response to the SARS-CoV-2 spike antigen ranging from 1 pg/mL to 10 ng/mL. Both methods were highly specific to detecting the SARS-CoV-2 spike antigen but not other antigens, including influenza A (i.e. H1N1), MERS-CoV and Streptococcus pneumoniae , even at high concentrations. [Display omitted] • The developed probe (AuNP-mAb) exhibits dual sensing mode for the detection of SARS-CoV-2 spike antigen (S-Ag). • AuNP-mAb allows viusal detection (colorimetric) of S-Ag with a detection limit of 48 ng/mL. • Electrochemical detection of S-Ag is achieved by a disposable screen-printed gold electrode with a detection limit of 1 pg/mL. • Neither method exhibits cross-reactivity with other viral proteins such as Influenza A, MERS-CoV and Streptococcus pneumoniae. • AuNP-mAb allows simple and rapid analysis of S-Ag in saliva sample. [ABSTRACT FROM AUTHOR]

• An RRS assay has been developed for the detection of Eca109 cell. • Antibody and aptamer multifunctional gold nanoparticles are used as cell probe. • The sensor has been successfully applied in serum samples. Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers in China. Early and accurate diagnosis is the key to effective treatment of this disease. In this work, a resonance Rayleigh scattering (RRS) strategy was established to determine the concentration of epidermal growth factor receptor (EGFR) over-expressed ESCC cancer cells, which based on the selective binding of the anti-EGFR aptamer (Apt) and anti-EGFR antibody (Ab) multi-functionalized gold nanoparticles (AuNPs) probe (Apt-AuNPs-Ab) to the EGFR-positive cancer cell. When the probe was mixed with the Eca109 ESCC cancer cell, a distinct RRS intensity increase was observed. The probe possesses a dynamic range from 1.0 × 102-5.0 × 105 cell·mL−1 for Eca109 cells, and the detection limit is 20 cell·mL−1. Experimental results with the A2780 ovarian cancer cells line, as well as with the Eca109 ESCC cancer cell line, clearly demonstrated that the RRS assay was sensitive and selective to Eca109 than the other cancer cell lines that express a low level of EGFR. The proposed RRS assay provided a novel platform for detection of EGFR-positive cancer cells and shown the good potential for clinical diagnostics. [ABSTRACT FROM AUTHOR]

Largemouth bass virus (LMBV) infection causes a lethal disease (ulcerative syndrome) in largemouth bass (Micropterus salmoides), which is an economically important freshwater fish species cultured in south-east China. For rapid detection of this virus, a simple and sensitive method was developed using probe-modified gold nanoparticles (AuNPs) as a colorimetric biosensor. A species-specific probe was attached to the surface of AuNPs, and thereby increasing the resistance of AuNPs to NaCl-induced aggregation. The NaCl concentration and ratio of probe to AuNPs in reaction mixture were evaluated, and the assay was optimized to detect only LMBV DNA sequence. Under optimum conditions, a linear relationship was observed between the ratio of A670/A520 and LMBV DNA concentrations over the range from 2.33 to 23.3 ng/μL and as low as 6.99 ng/μL of unamplied virus DNA could be detected only utilizing naked eyes. The entire assay was finished within 30 min, and the detection results were comparable to PCR examination in terms of reliability. Therefore, the visual assay is a potentially useful tool for aquaculture farmers to screen LMBV, and an ideal candidate for prevention and control of ulcerative syndrome in fish. • A colorimetric biosensor was used to visual detection of LMBV. • The linear detection was attained using LMBV DNA range from 2.33 to 23.3 ng/μL. • As low as 6.99 ng/μL unamplied LMBV DNA could be detected utilizing naked eyes. • The developed assay is suitable for rapid and on-site detection of LMBV. [ABSTRACT FROM AUTHOR]

• Centimeter-scale high nanoscale roughness AuNPs/AgNWs composites were prepared. • The longest length is 5 cm and the diameters ranged from 50 nm to 100 nm. • Many 20–50 nm AuNPs existed on nanocomposites which lead to high roughness. • The limiting concentration of Rhodamine B for this SERS substrates is 10−15 mol/L. A novel centimeter-scale gold nanoparticles (AuNPs)/silver nanowires (AgNWs) composites surface-enhanced Raman scattering (SERS) substrates prepared by vacuum thermal evaporation and solid-state ionics method at 9 μA direct-current electric field (DCEF) with fast ionic conductor KAg 4 I 5 films was reported. The surface morphologies, microstructures and chemical compositions of the AuNPs/AgNWs composites were characterized. The fractal dimensions of centimeter-scale AuNPs/AgNWs composites was calculated by grid covering method and the SERS performance was detected by Rhodamine B (RB) aqueous solution as probe molecules. The results show that the macroscopic dendritic AuNPs/AgNWs composites with the longest length of 5 cm were prepared, the diameters of AuNPs/AgNWs composites changed from 50 nm to 100 nm and many 20–50 nm AuNPs existed on the prepared nanocomposites, which lead to high nanoscale roughness AuNPs/AgNWs composites. The molar ratio of Ag:Au is 28.67:1 and the fractal dimensions of AuNPs/AgNWs composites was 1.67 because of more dentritic nanocomposites. The limiting concentration of RB for the prepared SERS substrates is 10−15 mol/L, which is far below the strictest safety limits required of RB in China. These results show that the prepared AuNPs/AgNWs composites with high nanoscale roughness, facile material synthesis, low detection concentration and simple detection procedure has strong application prospect in food safety. [ABSTRACT FROM AUTHOR]

The pesticide residues in agri-foods are threatening people's health. This study aims to establish a fast and low-cost surface-enhanced Raman scattering (SERS) method for the on-site detection of flumetsulam in wheat. The two-step modified concentrated gold nanoparticles (AuNPs) acted as the SERS substrate with the aid of NaCl and MgSO4. NaCl is served as the activator to modify AuNPs, while MgSO4 is served as the aggregating agent to form high-density hot spots. The activation and aggregation are two essential collaborative procedures to generate remarkable SERS enhancement and achieve the trace-level detection of flumetsulam. This method exhibits good enhancement effect with an enhancement factor of 106 and wide linear range (5–1000 μg/L). With simple pretreatment, the flumetsulam residue in real wheat samples can be successfully detected with the limit of detection (LOD) down to 0.01 μg/g, which is below the maximum residue limit of flumetsulam in wheat (0.05 μg/g) set in China. The recovery of flumetsulam residue in wheat ranges from 88.3% to 95.6%. These results demonstrate that the proposed SERS method is a powerful technique for the detection of flumetsulam in wheat, which implies the great application potential in the rapid detection of other pesticide residues in various agri-foods. [ABSTRACT FROM AUTHOR]

Geogas prospecting is a potential method for exploring concealed ore bodies. However, a knowledge gap still exists regarding the relationship between metal-bearing nanoparticles (NPs) found in geogas and concealed ore bodies. In this paper, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were applied to study the occurrence of metal-bearing NPs in ore, gouge and geogas samples collected from a fault zone and a background area of the concealed Shanggong gold deposit. SEM observations of ore rocks showed that gold was mainly concentrated in microfractures and its distribution was correlated with that of Mo, S, Pb, and Co. According to the results of SEM, gold can coexist with pyrites in the form of sub-microscopic particles, as NPs or dispersed in a lattice. TEM analysis and in situ SEM observations of ore rocks suggested that gold and other metallic particles can form during the process of mineralization. After mineralization, it is hypothesized that NPs can be generated by faulting and weathering. Meanwhile, morphological and chemical composition analyses indicate that aggregation and biological activity can change the status of NPs occurrence in fault gouges. TEM showed that there were more particles in the ascending geogas collected in the fault zone than in the background area. In terms of composition, particle samples collected from the background area were primarily non-metallic oxides and aluminium silicate. More metallic NPs containing Zn, Cu, Cr and Ni were observed in geogas collected in the fault zone. As for morphology, while the NPs in the fault zone geogas showed various morphologies, spherical dominated in geogas from the background area. These results suggest that NPs in ore rocks and gouge can be rapidly channelled to the surface through faults. The driving forces of NP transportation may include of temperature and pressure differences and the earth's magnetic field. This knowledge consolidates the view that NPs in geogas can provide information about the deep Earth. This study increases our knowledge of NPs in gold deposits, fault gouges and geogas, and enhances our understanding of NP generation and migration mechanism sin fault systems. • Gold coexists with pyrites in the form of sub-microscopic particles in ore rocks from Shanggong gold deposit. • A fault can act as both a migration channel and a producer of NPs • Aggregation and biological activity can change the status of NPs occurrence in fault gouges. • Temperature and pressure differences and the earth's magnetic field may transport NP from deep to shallow earth. • NPs in geogas can provide information about the deep Earth. [ABSTRACT FROM AUTHOR]

• Zoned pyrite is a recorder of ore-forming fluid activities and ore formation progresses. • EPMA and NanoSIMS elemental mappings show episodic ore-forming fluid activities. • Profile analyses show that the composition variation of ore fluid displayed as pulse manner. • Decoupling of As and Au implies high Cu in ore fluid inhibits its Au-carrying capability. • The narrow S isotope range of −5−+5‰ with geophysical evidences imply a magmatic origin for the Au deposits. The Youjiang basin in southwestern China is known for the occurrence of abundant Carlin-type gold deposits similar to those of northern Nevada in the U.S. Among them, Taipingdong is a representative deposit nearby the super-large Shuiyindong Mine in the Huijiabao ore field. Though some data of in-situ sulfur isotopes and trace element geochemistry of pyrite have been collected recently, the ore-forming fluid source and genesis model of the deposits remain under debate. The mineral chemistry and isotopic compositions of Au-carrying pyrite in the Taipingdong gold deposit were studied in detail using nanoscale secondary ion mass spectroscopy (NanoSIMS) in this study to further understand the aforementioned issues. Petrographic observations identified two types of pyrite: syn -sedimentary framboidal pyrites and hydrothermal pyrites. Back-scattered electron observations and electron microprobe analysis elemental mapping showed that the latter have three generations, termed as As-poor Py1 (the core), As-rich Py2 (the middle overgrowth), and As-weak Py3 (the outmost overgrowth zone), respectively. NanoSIMS high-resolution multiple elemental maps showed the following: 1) Py1 is poor in As and other trace elements; Py2 is rich in As and Cu and relatively rich in Se; and Py3 is rich in Au and relatively rich in As, Cu, and Se. 2) Gold is heterogeneously distributed as solid solution and nanoparticle, focusing on the outermost rim of the zoned pyrite (Py3). Other metal nanoparticles of Cu, Se, and Pb were identified in Py2 or Py3. 3) Arsenic elemental mapping showed dense mineral growth of pyrite in the subzones. 4) Line profile analyses of trace elements showed high Cu contents in Py2 and Py3 and that As is positively correlated with Cu but not with Au. In-situ sulfur isotopic analyses showed that the δ34S values range from −15.4‰ to 6.1‰ with a median of 2.0‰ for Py1, from −1.8‰ to 7.1‰ with a median of 1.4‰ for Py2, and from −3.0‰ to 6.2‰ with a median of 3.9‰ for Py3. Intensive spot analyses showed a slight fluctuation in S isotopic values within a short distance in pyrite subzones. The δ34S values of Py2 and Py3 dropped into a narrow range from −3‰ to 6‰ with a median of 3.3‰. Considering the composition and isotopic characteristics, Py1 is classified as pre-ore pyrite and Py2 and Py3 as ore pyrites with Py3 representing the Au climax event. The Au state and distribution in the pyrite of the Taipingdong deposit imply that the ore-forming fluid was unsaturated for Au, but occasionally hosted metal nanoparticles. The Au climax event occurred towards the end of the fluid evolution. The decoupling of As and Au in the ore pyrites indicate that the Au-carrying capacity of the pyrite was limited by the higher concentration of Cu ions in the ore-forming fluids. The S isotopic data of the Taipingdong deposit is similar to the available in-situ S isotopic range of −5‰ to 5‰ of the representative Au deposits in the basin except for the Lannigou (Zhenfeng) Mine. The S isotopic deviation of pyrite in the Huijiabao ore field to the typical magmatic fluid (±0‰) may be the result of a mixture of hydrothermal and basin fluid to a certain extent. This feature combined with the intensive fluctuation of trace elements and isotopic compositions over a short duration accord with the characteristics of magmatic hydrothermal fluid. Combined with the strong silicification characteristic of the host rock and the previous geophysical works in the ore district, a magmatic hydrothermal model might be suitable for the Taipingdong gold deposit and even other Carlin-type gold deposits in the Youjiang basin. [ABSTRACT FROM AUTHOR]

The procurance of gold nanoparticles in the plant extracts is an excellent way to attain nanomaterials natural and eco-friendly nanomaterials. The Dehydrated roots of Chinese Euphorbia fischeriana flowering plant are called "Lang-Du". In this study, the retrieving of gold nanoparticles from Euphorbia fischeriana root was amalgamated by standard procedure. Fabricated gold nanoparticles were portrayed through the investigations of ultraviolet and visible spectrophotometry (UV–Vis), Fourier transform infrared spectroscopy (FTIR), High resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The UV–Vis and FTIR results explicated the obtained particles were sphere-shaped and the terpenoids of Euphorbia fischeriana had strong communications with gold surface. The HRTEM and XRD images exposed the produced gold nanoparticles had an extreme composition of crystal arrangement and excellent uniformed size of particles. In our study, the Isoprenaline induced myocardial damage established the elevation in TBARS, LOOH of heart tissues and notable decline in antioxidant enzymes SOD, CAT, GPx, and GSH. This biochemical result was additionally proved by histopathological assessment. Remarkably, the pretreatment with EF-AuNps(50 mg/kg b.w) illustrated stabilized levels of serum creatine and cardiotropins in myocardial infarcted animals. And further we understood the essential function of NF-ƙB, TNF-α, IL-6 signaling molecules and its way progression in the development of vascular tenderness. • Myocardial infarction (MI), the well-known heart sickness with high transience speed, in China • Ultrastructure and morphological examination further confirms the effect of EF-AuNps on isoprenaline induced animals • Further the inflammatory marker studies eventually corroborate the effect of EF-AuNps in molecular level [ABSTRACT FROM AUTHOR]

As humans and climate change continue to alter the landscape, novel disease risk scenarios have emerged. Sever fever with thrombocytopenia syndrome (SFTS), an emerging tick-borne infectious disease first discovered in rural areas of central China in 2009, is caused by a novel bunyavirus (SFTSV). The potential for SFTS to spread to other countries in combination with its high fatality rate, possible human-to-human transmission, and extensive prevalence among residents and domesticated animals in endemic regions make the disease a severe threat to public health. Because of the lack of preventive vaccines or useful antiviral drugs, diagnosis of SFTS is the key to prevention and control of the SFTSV infection. The development of serological detection methods will greatly improve our understanding of SFTSV ecology and host tropism. We describe a highly sensitive protein detection method based on gold nanoparticles (AuNPs) and enzyme-linked immunosorbent assay (ELISA)-AuNP-based ELISA. The optical sensitivity enhancement of this method is due to the high loading efficiency of AuNPs to McAb. This enhances the concentration of the HRP enzyme in each immune sandwich structure. The detection limit of this method to the nucleocapsid protein (NP) of SFTSV was 0.9 pg mL -1 with good specificity and reproducibility. The sensitivity of AuNP-based ELISA was higher than that of traditional ELISA and was comparable to real-time quantitative polymerase chain reaction (qRT-PCR). The probes are stable for 120 days at 4 °C. This can be applied to diagnosis and hopefully can be developed into a commercial ELISA kit. The ultrasensitive detection of SFTSV will increase our understanding of the distribution and spread of SFTSV, thus helping to monitor the changes in tick-borne pathogen SFTSV risk in the environment., Competing Interests: The authors declare no conflict of interest.

The Maritime Silk Road was the major trade route between eastern and western civilizations in the Middle Ages. However, hardly any silk products have been found along the transoceanic trade route. Thus, the extrasensitive detection of silk relic traces has tremendous importance in research regarding the Maritime Silk Road. In this study, an electrochemical immunosensor based on a tailored monoclonal antibody and gold nanoparticles using the layer-by-layer self-assembly method was devised. The fabricated immunosensor demonstrated preeminent performance in the analysis of silk fibroin, with a linear detection range of 0.01-100 ng mL -1 and a detection limit of 3.8 pg mL -1 . In particular, the performance of the immunosensor was excellent in the analysis of ancient silk samples, especially in the qualitative and quantitative detection of soil samples extracted from Nanhai No. 1 shipwreck archeological sites. The proposed electrochemical immunosensor proves the existence of silk products on the Maritime Silk Road and demonstrates enormous potential for studying the formation and development of the ancient transoceanic trading route.

Spiroplasma eriocheiris is an emerging pathogen in freshwater crustaceans. In recent years, Eriocheir sinensis, Procambarus clarkii, Litopenaeus vannamei, Macrobrachium rosenbergii and Macrobrachium nipponense had been infected by this pathogen in China. An immunochromatographic strip test using gold nanoparticles was developed for rapidly detecting this pathogen. The strip test based on the principle of sandwich immunoassay by the specific combination between the pathogen and polyclonal antibody on a nitrocellulose membrane. Positive samples were displayed as red lines at the test and control zones of the nitrocellulose membrane, while negative samples resulted in a red line only at the control zone. The limit of detection was proved to be 10 6 Color Change Unit/ml. The test strip could be visually detected within 15 min and do not have cross-reaction with other aquatic bacteria. This test strip allows on-site rapid detection of S. eriocheiris in crustacean without the requirement of specialized equipment and professional personnel. The one-step test strips developed in our study had high sensitivity, specificity, reproducibility and stability. In conclusion, this method was proved to be convenient, feasible, rapid and effective for detecting S. eriocheiris., (© 2017 John Wiley & Sons Ltd.)

This paper describes a new amplified immunoassay with horseradish peroxidase (HRP) and antibody (Ab) labeled gold nanoparticles (AuNPs) probe hyphenated to capillary electrophoresis (CE) with electrochemical (EC) detection for ultrasensitive determination of ciguatoxin CTX1B. AuNPs were conjugated with HRP and Ab, and then incubated with limited amount of CTX1B to produce immunocomplex. The immunoreactive sample was injected into capillary for CE separation and EC detection. Enhanced sensitivity was obtained by adopting the AuNPs as carriers of HRP and Ab at high HRP/Ab molar ratio. The calibration curve of CTX1B was in the range of 0.06-90 ng/mL. The detection limit was 0.045 ng/mL, which is 38-fold lower than that of HPLC-MS method for CTX1B analysis. The proposed method was successfully applied for the quantification of CTX1B in contamined fish samples by simultaneously labeling Ab and HRP on AuNPs. The amplified IA with HRP and Ab labeled AuNPs probe hyphenated to CE and EC detection provides a sensitive analytical approach for the determination of trace ciguatoxin in complex samples., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

A novel unmodified gold nanoparticles (AuNPs)-based colorimetric strategy for label-free, specific and sensitive mercury ion (Hg(2+)) detection was demonstrated by using thymine-Hg(2)(+)-thymine (T-Hg(2)(+)-T) recognition mechanism and hybridization chain reaction (HCR) amplification strategy. In this protocol, a structure-switching probe (H0) was designed to recognize Hg(2+) and then propagated a chain reaction of hybridization events between two other hairpin probes (H1 and H2). In the absence of Hg(2+), all hairpin probes could stably coexist in solution, the exposed sticky ends of hairpin probes were capable of stabilizing AuNPs. As a result, salt-induced AuNPs aggregation could be effectively prevented. In the presence of Hg(2+), thymine bases of H0 could specifically interact with Hg(2+) to form stable T-Hg(2)(+)-T complex. Consequently, the hairpin structure of H0 probe was changed. As H1/H2 probes were added, the HCR process could be triggered and nicked double-helixes were formed. Since it was difficult for the formed nicked double-helixes to inhibit salt-induced AuNPs aggregation, a red-to-blue color change was observed in the colloid solution as the salt concentration increased. With the elegant amplification effect of HCR, a detection limit of around 30 nM was achieved (S/N=3), which was about 1-2 orders of magnitudes lower than that of previous unmodified AuNPs-based colorimetric methods. By using the T-Hg(2)(+)-T recognition mechanism, high selectivity was also obtained. As an unmodified AuNPs-based colorimetric strategy, the system was simple in design, convenient in operation, and eliminated the requirements of separation processes, chemical modifications, and sophisticated instrumentations., (Copyright © 2014 Elsevier B.V. All rights reserved.)