Plasmon AgNPs/MoS2/ZnO nanorods array ternary heterojunctions enabling high-efficiency solar-light energy utilization for photocatalysis and recyclable SERS detection.

BACKGROUND: Surface-enhanced Raman scattering (SERS) has gained widespread use in molecule-level detection benefiting from its high sensitivity, nondestructive data acquisition, and capacity for providing molecular fingerprint information. However, the strong adhesion of target molecules to the substrate (known as the "memory effect") inherently hinders the reusability of SERS substrates. Research has shown that self-cleaning SERS substrates based on versatile semiconductor materials with SERS enhancement capabilities and solar photocatalytic properties offer an effective platform for the sensitive detection and degradation of harmful molecules. RESULTS: In this research, a resuable SERS-active substrate was facilely fabricated by anchoring silver nanoparticles (AgNPs) to the edges of MoS2 nanosheet decorated on ZnO nanorod arrays (NRAs). This innovative design exhibited a remarkable SERS enhancement factor (EF) of 4.6 × 107 and demonstrated significant solar photocatalytic efficiency. Such superior characteristics of ternary plasma heterojunction were ascribable to the synergistic effect of the "Schottky barrier" and "hot spots" between MoS2 and AgNPs, the inherent chemical enhancement proficiency of the MoS2/ZnO NRAs heterojunction, as well as the ultrafast electron transfer within the ternary heterojunction. SIGNIFICANCE: The developed ternary heterojunction substrate enabled highly sensitive SERS detection of trace amounts of organic molecules. Moreover, this SERS substrate exhibited self-cleaning and recyclability via solar-light-driven photocatalysis. This bifunctional recyclable SERS substrate proved capable of meeting various requirements for routine monitoring of environmental organic pollutants and provided a robust avenue for advancing energy utilization materials that serve as high-performance SERS sensors and catalysts.

Surface-engineered Mo2B: a promising electrode material for constructing Ohmic contacts with blue phosphorene for electronic device applications.

The Schottky barrier between a metal and a semiconductor plays an important role in determining the transport efficiency of carriers and improving the performance of devices. In this work, we systematically studied the structure and electronic properties of heterostructures of blue phosphorene (BP) in contact with Mo2B based on density functional theory. The semiconductor properties of BP are destroyed owing to strong interaction with bare Mo2B. The effect of modifying Mo2B with O and OH on the contact properties was investigated. A p-type Schottky contact can be obtained in BP/Mo2BO2. The height of the Schottky barrier can be modulated by interlayer distance to realize a transition from a p-type Schottky contact to a p-type Ohmic contact in BP/Mo2BO2. The BP/Mo2B(OH)2 forms robust Ohmic contacts, which are insensitive to interlayer distance and external electric fields due to the Fermi level pinning effect. Our work provides important clues for contact engineering and improvement of device performance based on BP.

AQP4 regulates ferroptosis and oxidative stress of Muller cells in diabetic retinopathy by regulating TRPV4.

Diabetic retinopathy (DR) is a common microvascular complication that causes visual impairment or loss. Aquaporin 4 (AQP4) is a regulatory protein involved in water transport and metabolism. In previous studies, we found that AQP4 is related to hypoxia injury in Muller cells. Transient receptor potential cation channel subfamily V member 4 (TRPV4) is a non-selective cation channel protein involved in the regulation of a variety of ophthalmic diseases. However, the effects of AQP4 and TRPV4 on ferroptosis and oxidative stress in high glucose (HG)-treated Muller cells are unclear. In this study, we investigated the functions of AQP4 and TRPV4 in DR. HG was used to treat mouse Muller cells. Reverse transcription quantitative polymerase chain reaction was used to measure AQP4 mRNA expression. Western blotting was used to detect the protein levels of AQP4, PTGS2, GPX4, and TRPV4. Cell count kit-8, flow cytometry, 5,5',6,6'-tetrachloro-1,1,3,3'-tetraethylbenzimidazolyl carbocyanine iodide staining, and glutathione (GSH), superoxide dismutase (SOD), and malondialdehyde (MDA) kits were used to evaluate the function of the Muller cells. Streptozotocin was used to induce DR in rats. Haematoxylin and eosin staining was performed to stain the retina of rats. GSH, SOD, and MDA detection kits, immunofluorescence, and flow cytometry assays were performed to study the function of AQP4 and TRPV4 in DR rats. Results found that AQP4 and TRPV4 were overexpressed in HG-induced Muller cells and streptozotocin-induced DR rats. AQP4 inhibition promoted proliferation and cell cycle progression, repressed cell apoptosis, ferroptosis, and oxidative stress, and alleviated retinal injury in DR rats. Mechanistically, AQP4 positively regulated TRPV4 expression. Overexpression of TRPV4 enhanced ferroptosis and oxidative stress in HG-treated Muller cells, and inhibition of TRPV4 had a protective effect on DR-induced retinal injury in rats. In conclusion, inhibition of AQP4 inhibits the ferroptosis and oxidative stress in Muller cells by downregulating TRPV4, which may be a potential target for DR therapy.

DEAR model in overweight endometrial cancer patients undergoing fertility-sparing treatment: A randomized controlled trial.

OBJECTIVE: To evaluate the effects of DEAR weight management in overweight patients undergoing fertility-sparing treatment for endometrial cancer or atypical hyperplasia. METHODS: Women with endometrial cancer or atypical hyperplasia who received fertility-sparing treatment and had a body mass index of >25 kg/m2 were randomly allocated to the DEAR (DEAR weight management) and control (self weight management) groups. Body morphology and composition, glycolipid metabolism, and tumor outcomes were assessed in both groups before and at 3 and 6 months after intervention. RESULTS: Overall, 72 subjects were included (36 in each group). Following intervention, the DEAR group showed significantly lower median body weight (69.45 vs. 78.05), body mass index (26.19 vs. 29.15), lipid accumulation index (29.21 vs. 57.86), body fat mass (24.00 vs. 29.30), visceral fat area (112.5 vs. 133.3), and glycolipid metabolic indices (except high density lipoprotein) than the control group (P < 0.05) and showed a decreasing trend. The test group achieved significantly higher complete remission (88.46% vs. 57.14%; P < 0.05); the time to complete remission did not differ significantly (P > 0.05). CONCLUSIONS: DEAR weight management can improve the studied parameters and complete remission rates in this population. REGISTRATION: NCT06169449.

Microfluidic paper-based analysis device applying black phosphorus nanosheets@MWCNTs-COOH: A portable and efficient strategy for detection of ß-Lactoglobulin in dairy products.

This study prepared a novel, portable and cost-effective microfluidic paper-based electrochemical analysis device (µ-PAD) using black phosphorus nanosheets@carboxylated multi-walled carbon nanotubes (BPNSs@MWCNTs-COOH) nanocomposites for ß-lactoglobulin (ß-LG) detection. At the appreciate ratio, the synthesized BPNSs@MWCNTs-COOH was demonstrated to not only serve as a high-quality substrate for the specific aptamer immobilization, but also improve the electron transfer capability of the sensing interface. The µ-PADs, utilizing BPNSs@MWCNTs-COOH and aptamer recognition, exhibited a wider detection range (10-1000 ng mL-1) and lower detection limit (LOD: 0.12 ng mL-1) for ß-LG, and demonstrated enhanced specificity, satisfactory anti-interference ability and stability. When applied to the ß-LG determination in dairy samples, the µ-PAD yielded ß-LG concentrations highly correlated with those obtained using the HPLC method (R2: 0.9982). These results emphasized the reliable performance of the developed µ-PADs in ß-LG allergen quantification, highlighting their potential as an efficient platform for the rapid screening of ß-LG allergens.

Bimetallic Ag/Au nanoclusters encapsulated in ZIF-8 framework: A novel strategy for ratiometric fluorescence detection of doxycycline in food.

This study successfully encapsulated the Ag+-doped Au nanoclusters (Ag/AuNCs) within the ZIF-8 framework to construct a novel Ag/AuNCs@ZIF-8 ratiometric fluorescent probe for the antibiotic doxycycline (DOX) detection. The incorporation of Ag+ contributed to the fluorescence enhancement of the nanoclusters through the "silver effect", consequently improving the stability of the developed bimetallic Ag/AuNCs. Furthermore, the encapsulation of bimetallic Ag/AuNCs within the ZIF-8 framework restricted their intramolecular vibrations, resulting in further amplification of fluorescence intensity at 595 nm. The ZIF-8 also sensitized the restoration of DOX green fluorescence at 515 nm. Within the concentration range of 0.001-20 µg mL-1, the ratio of fluorescence intensity (F515/F595) exhibited a favorable linearity for DOX concentration, with a detection limit of 36.8 ng mL-1. This ratiometric fluorescence approach had the promising potential for accurate and efficient quantitative detection of DOX residue in food and served as a valuable reference for rapid monitoring of food contaminants.

Carbon-dots encapsulated luminescent metal-organic frameworks@surface molecularly imprinted polymer: A facile fluorescent probe for the determination of chloramphenicol.

In this study, carbon dots (CDs)-encapsulated luminescent metal-organic frameworks@surface molecularly imprinted polymer (CDs@MOF@SMIP) was facilely prepared and applied as fluorescent probe for specific identification and sensitive detection of chloramphenicol (CAP) in food. Fluorescent CDs, serving as signal tags, were encapsulated within metal-organic backbones (ZIF-8), yielding luminescent MOF materials (CDs@ZIF-8). The synthesized CDs, CDs@ZIF-8 and CDs@ZIF-8@SMIP were investigated by morphological and structural characterizations (UV-Vis, XRD, FT-IR, BET, TEM). The CDs@ZIF-8@SMIP probe was demonstrated to have remarkable selectivity and sensitivity towards CAP. Its fluorescence decreased linearly with CAP concentration from 0.323 µg L-1 (0.001 µM) to 8075.0 µg L-1 (25.0 µM), featuring a low detection limit of 0.08 µg L-1. The CDs@ZIF-8@SMIP-based fluorescence strategy achieved satisfactory recoveries (95.5 % - 101.0 %) in CAP-spiked commercial foods with RSD < 4.4 % (n = 3). These results indicate that this method can effectively detect trace CAP in food matrices and has broad application prospects.

Computational simulation-assisted design and experimental verification of molecularly imprinted polymers for selective extraction of chlorogenic acid.

Chlorogenic acid (CGA) is an active ingredient in honeysuckle with a broad-spectrum of antibacterial activity, suppressing tumor growth and other pharmacological effects. However, it is susceptible to damage during traditional extraction and separation processes. Therefore, developing selective and efficient extraction methods of CGA is essential. Based on computational molecular simulations, a reliable and efficient molecularly imprinted polymers (MIPs) were successfully developed for selective extraction of CGA. MIPs and non-molecularly imprinted polymers (NIPs) were synthesized using a precipitation polymerization method, employing three different functional monomers: [methacrylic acid (MAA), 4-vinylpyridine (4-VP), and methyl methacrylate (MMA)], with CGA serving as the template molecule. To simulate the polymers and predict the optimal ratio between the template and functional monomer, the computational studies and adsorption performance experiments were carried out. The adsorption characteristics and thermal stability of polymers were evaluated by isothermal adsorption, adsorption kinetics, selective adsorption and thermogravimetric analysis, aiming to obtain the MIPs with specific recognition and selectivity for CGA. When the molar ratio of template CGA to functional monomer 4-VP was 1:8, the prepared MIPs was found to have the maximum adsorption capacity (14.85 mg g-1) and the highest imprinting factor (1.74) at the CGA concentration of 100 mg L-1. These results were consistent with those obtained by computational molecular simulation. This study not only provides good guidance for developing separation materials for extracting CGA from natural plants but also inspires the application of computer simulation and molecular docking techniques in the preparation of specific MIPs materials.

A sensitive "turn-on" Schiff-base fluorescent probe for the selective detection of Fe3+ and bio-imaging.

A novel Schiff-base fluorescent probe, 4-(N-(2- hydroxyl-1-naphthalymethylimino)-ethylamino) -7-nitro-1,2,3-benzoxadiazole (HENB) was synthesized and utilized for spectral sensing of Fe3+ ions at neutral pH. The binding of Fe3+ to HENB in C2H5OH-HEPES buffer (1:1 v/ v, 25 mM, pH 7.2) resulted in a pronounced emission enhancement at 530 nm, which is possibly due to the inhibition of photo-induced electron transfer (PET) process as well as the chelation enhanced fluorescence (CHEF) effect. HENB shows good selectivity and sensitivity toward Fe3+ with the detection limit as low as 4.51 nM. Test strips made of HENB was used for rapid "naked-eye" detection of Fe3+ ions in aqueous medium. Moreover, HENB was successfully applied in fluorescence imaging of exogenous and endogenous Fe3+ in live Hela cells as well as zebrafish. Importantly, HENB is capable of effectively monitoring the variations of Fe3+ in living cells during ferroptosis process.

Nanoscale Materials Applying for the Detection of Mycotoxins in Foods.

Trace amounts of mycotoxins in food matrices have caused a very serious problem of food safety and have attracted widespread attention. Developing accurate, sensitive, rapid mycotoxin detection and control strategies adapted to the complex matrices of food is crucial for in safeguarding public health. With the continuous development of nanotechnology and materials science, various nanoscale materials have been developed for the purification of complex food matrices or for providing response signals to achieve the accurate and rapid detection of various mycotoxins in food products. This article reviews and summarizes recent research (from 2018 to 2023) on new strategies and methods for the accurate or rapid detection of mold toxins in food samples using nanoscale materials. It places particular emphasis on outlining the characteristics of various nanoscale or nanostructural materials and their roles in the process of detecting mycotoxins. The aim of this paper is to promote the in-depth research and application of various nanoscale or structured materials and to provide guidance and reference for the development of strategies for the detection and control of mycotoxin contamination in complex matrices of food.

Management of priming fluids in cardiopulmonary bypass for adult cardiac surgery: network meta-analysis.

BACKGROUND: Cardiopulmonary bypass (CPB) is frequently employed for cardiac surgery, and selecting a suitable priming fluid is a prerequisite for CPB. Currently, the commonly used priming fluids in clinics are classified as crystalloids and colloids, including balanced crystalloids, albumin, dextran, gelatin and hydroxyethyl starch (HES). This network meta-analysis compared the effects of eight fluids used during CPB in adults to determine optimal priming fluid during CPB surgery. METHODS: Randomised controlled trials assessing priming fluids for CPB in adult cardiac surgery published before 13 April 2023 were searched across Ovid MEDLINE(R) ALL, OVID EMbase, and Cochrane Central Register of Controlled Trials. Various priming fluids were classified into eight categories, including balanced crystalloids, 0.9% NaCl, iso-oncotic human albumin, hyperoncotic human albumin, HES with molecular weight 130k, HES with molecular weight 200k, gelatin and dextran. RESULTS: The NMA of platelet counts revealed no significant differences in any result. In direct comparison results, only the comparison of HES with molecular weight 130k vs. gelatin (standard mean difference = -0.40, 95% confidence interval [95%CI: -0.63, -0.16) revealed a significant difference. According to the SUCRA, balanced crystalloids had the highest platelet count, followed by gelatin, and HES with a molecular weight of 130k had the lowest platelet, followed by HES with a molecular weight of 200k. CONCLUSION: Patients using dextran have a low mortality rate and a short mean CPB time, the use of balanced crystalloids is beneficial in terms of platelet count, and HES with molecular weight 130k is beneficial for postoperative urine volume at 24h. However, all priming fluids have pros and cons quite, and the optimal choice of priming fluids remains unsupported by current evidences. When performing CPB surgery, the type of priming fluid should be selected according to the actual situation in CPB for adult cardiac surgery.

When dextran was used as the CPB priming fluid, patients had the lowest mortality and shortest mean CPB time.With iso-oncotic HA, patients had the shortest length of ICU stay, the least blood loss 24h after surgery, and the lowest chest tube output 24h after surgery.The use of balanced crystalloids was beneficial for platelet count, the use of L-HES was beneficial for urine output 24h after surgery, and the use of H-HES resulted in the shortest hospital stay.In summary, each of these fluids has pros and cons quite, and an optimal choice of priming fluids during CPB surgery remains unsupported by current evidence.When performing CPB surgery, the type of priming fluids should be selected according to the actual condition of the patient's body.

Nanomaterial-based magnetic surface molecularly imprinted polymers for specific extraction and efficient recognition of dibutyl phthalate.

A rapid and selective sorbent for the enrichment of dibutyl phthalate (DBP) from water and Chinese Baijiu samples was established using magnetic surface molecularly imprinted polymers (MSMIPs) combined with gas chromatography-mass spectrometer (GC-MS). The MSMIPs were synthesized using a magnetic nanosphere material with silica layer, increasing the polymer surface area as a carrier. Compared with the traditional methods, the addition of magnetic microspheres simplified the process of food substrate purification and significantly shortened the pre-concentration time. The MSMIPs adsorption conforms to the Freundlich isotherm model as multilayer adsorption on an inhomogeneous surface and the pseudo-second-order model. The developed MSMIPs combined with GC-MS method showed good linearity in DBP concentration range of 0.02-1.0 mg L-1 with low LOD (0.0054 mg L-1) and LOQ (0.018 mg L-1), and obtained good recoveries in real samples (95.2-97.2%) with RSD < 5.0% (n = 9), which were consistent with those from Chinese national standard method.

Review: Synthesis of metal organic framework-based composites for application as immunosensors in food safety.

Ensuring food safety continues to be one of the major global challenges. For effective food safety monitoring, fast, sensitive, portable, and efficient food safety detection strategies must be devised. Metal organic frameworks (MOFs) are porous crystalline materials that have attracted attention for use in high-performance sensors for food safety detection owing to their advantages such as high porosity, large specific surface area, adjustable structure, and easy surface functional modification. Immunoassay strategies based on antigen-antibody specific binding are one of the important means for accurate and rapid detection of trace contaminants in food. Emerging MOFs and their composites with excellent properties are being synthesized, providing new ideas for immunoassays. This article summarizes the synthesis strategies of MOFs and MOF-based composites and their applications in the immunoassays of food contaminants. The challenges and prospects of the preparation and immunoassay applications of MOF-based composites are also presented. The findings of this study will contribute to the development and application of novel MOF-based composites with excellent properties and provide insights into advanced and efficient strategies for developing immunoassays.

Electrochemical sensor applying ZrO2/nitrogen-doped three-dimensional porous carbon nanocomposite for efficient detection of ultra-trace Hg2+ ions.

In this study, a ZrO2/nitrogen-doped three-dimensional porous carbon (ZrO2/N-3DPC) nanocomposite was manufactured to fabricate an effective electrochemical sensor for the detection of ultra-trace mercury ion (Hg2+). The synthesized N-3DPC had an open pore structure, large specific surface area and enough continuous mass transfer channels, which can facilitate the diffusion and transmission of electrons and ions at the sensing interface, providing an effective adhesion platform for electrochemical deposition of ZrO2 nanoparticles. Benefiting from the synergistic effect of ZrO2 and N-3DPC, the developed electrochemical sensor had good adsorption and catalytic performance for Hg2+ with a wider linear range of 0.1-220 µg L-1 and a lower detection limit of 0.062 µg L-1. Meanwhile, the sensor exhibited remarkable repeatability, reproducibility, stability and anti-interference, and was further applied to detect Hg2+ in seafood and tap water with satisfactory recoveries (97.1-103.1%) and lower relative standard deviation (≤4.3%). The proposed strategy of electrochemical sensing detection of Hg2+ provides a new idea and direction for the research of ZrO2/N-3DPC nanocomposite in the field of analysis and detection, which is also of great significance to ensure foods, environmental safety and human health.

A theoretical study of laser-induced ultrafast spin dynamics in trigonal monopyramidal iron and nickel complexes.

We present a first-principles study of the geometries, electronic structures, and laser-induced ultrafast spin dynamics in four trigonal monopyramidal complexes [tpat-BuFe]-, [tcmat-BuFe]-, [tpat-BuNi]-, and [tcmat-BuNi]- [tpa: tris-(pyrrolylmethyl)amine; tcma: tris(carbamoyl-methyl)amine; t-Bu: tert-butyl]. It is found that the low-lying level distribution of the four structures is similar, however, their spin and charge localization differs substantially. Detailed analysis demonstrates that the iron complexes have much more singly spin localized states located in the low energy region, while the nickel complexes have more charge-transfer (CT) states and more states with spin equally distributed between the Ni and the ligands. Affected by these features, more ultrafast spin-crossover (SCO) scenarios are achieved in the two iron complexes, and better CT dynamics is obtained in nickel complexes. In particular, for the CT scenarios combined with spin bifurcation, the charge is transferred from the tpa/tcma ligand to the Fe/Ni atoms, while spin-density transfer occurs in the opposite direction. Among the scenarios illustrated in the paper, the SCO processes turn out to be more complicated since they involve many more intermediate states and exhibit relatively low fidelity. In addition, the transferability of each scenario is analyzed from the absorption spectra of the initial and final states. All these results can provide significant insights into the electronic and magnetic natures of the four complexes, guide the experimental realization of the relevant scenarios, and thus promote their applications in molecular spintronics.

One-pot Synthesis of Metal-coordinated Covalent Organic Frameworks for Enhanced CO2 Photoreduction.

Solar energy-driven reduction of CO2 into fuels with H2O as a sacrificial agent is a challenging but desirable subject in photosynthesis. Covalent organic frameworks (COFs) are considered promising candidates for this subject because of their designable structures and functions. The coordination of transition metal ions into COFs is a feasible way to boost the photocatalytic activity. However, postsynthetic modification of COFs with metal ions often leads to a significant decrease in crystallinity and the specific surface area. Herein, we develop a one-pot synthesis of metal-coordinated (nonnoble metal) COFs with high crystallinity. HB-TAPT + Co with ordered and segregated D-A arrays is synthesized by combining 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT, a strong electron-acceptor) with 2-hydroxy-1,3,5-benzenetricarbaldehyde (HB)-loaded Co2+ (a strong electron-donor). The CO production when using HB-TAPT + Co under visible light irradiation for 4 h is 78.4 µmol g-1, which is 3.2 times that of HB-TAPT + Co synthesized by the postsynthetic modification method and 2.65 times that of HB-TAPT without the metal ions. HB-TAPT + Co also has good recycling stability in photocatalytic CO2 reduction. Additionally, experimental results have demonstrated that the crystallinities of these metal-coordinated materials contribute greatly to the conversion of CO2 in the photoreaction with H2O. This work provides a new protocol for improving the CO2 photoreduction performance by coordinating metal ions to COFs while maintaining the original crystallinity through a one-pot synthesis method.

Azo-Branched Covalent Organic Framework Thin Films as Active Separators for Superior Sodium-Sulfur Batteries.

Sodium-Sulfur (Na-S) batteries are outstanding for their ultrahigh capacity, energy density, and low cost, but they suffer from rapid cell capacity decay and short lifespan because of serious polysulfide shuttle and sluggish redox kinetics. Herein, we synthesize thin films of covalent organic frameworks (COFs) with azobenzene side groups branched to the pore walls. The azobenzene branches deliver dual functions: (1) narrow the pore size to the sub-nanometer scale thus inhibiting the polysulfide shuttle effect and (2) act as ion-hopping sites thus promoting the Na+ migration. Consequently, the Na-S battery using the COF thin film as the separator exhibits a high capacity of 1295 mA h g-1 at 0.2 C and an extremely low attenuation rate of 0.036% per cycle over 1000 cycles at 1 C. This work highlights the importance of separator design in upgrading Na-S batteries and demonstrates the possibility of functionalizable framework materials in developing high-performance energy storage systems.

Superabsorbent hydrogel as a formulation to promote mineralization and accelerate degradation of acetochlor in soils.

The excessive use of herbicides had caused serious environmental pollution and ecological problems. Therefore, it is imperative to explore an effective method to reduce herbicide residues and pollution. In the present study, we used superabsorbent hydrogels coated 14C-acetochlor (SH-ACE) to investigate its behavior in different soils under oxic conditions. After 100 days, the mineralization by SH-ACE was increased by 2.3%, 2.5% and 3.3% in the red clay soils, fluvio-marine yellow loamy soils and coastal saline soils, respectively, compared to the control group. This result indicated that the SH-ACE treatment resulted in more complete degradation and detoxification of acetochlor. In addition, the dissipation rates of acetochlor were significantly faster in the SH-ACE treatment, which reduced the persistence of acetochlor. The probable degradation pathways of acetochlor involved dechlorination, hydroxylation, deethoxymethylation, and the formation of thioacetic acid derivatives in the two treatments, but the contents of transformation products were completely different. These findings suggest that the SH-ACE treatment has a significant effect to accelerate the degradation of acetochlor. When developing green pesticides, we emphasize that superabsorbent hydrogel coating treatment should be considered as a promising method for ecological safety in the environment.

Effective adsorption and in-situ SERS detection of multi-target pesticides on fruits and vegetables using bead-string like Ag NWs@ZIF-8 core-shell nanochains.

In-situ, real-time and sensitive detection of multiple pesticide residues in food is always an important issue in food safety. Herein, a novel multifunctional bead-string like Ag nanowires@zeolitic imidazolate framework-8 (Ag NW@ZIF-8) core-shell nanochains was successfully synthesized and utilized as surface-enhanced Raman scattering (SERS) substrate for in-situ and simultaneous detection of pesticide residues. Due to the microporous framework structure of ZIF-8 shell and the plasmon property of Ag NWs core, the Ag NWs@ZIF-8 composite was demonstrated to have strong adsorption performance and high SERS activity (enhancement factor: 4.6 × 107). The Ag NWs@ZIF-8 based SERS strategy achieved sensitive detection of two water-insoluble pesticides methylparathion and carbaryl with detection limits as low as 7.6 × 10-9 M and 5.7 × 10-9 M, as well as the in-situ detection of multi-pesticide residues on fruits and vegetables with acceptable recovery ranged from 77.4 % to 117.5 %, demonstrating its great potential for in-situ and rapid detection of food contaminants.