Surface-enhanced Raman spectroscopy substrates for monitoring antibiotics in dairy products: Mechanisms, advances, and prospects.

Antibiotic residues in dairy products have become an undeniable threat to human health. Surface-enhanced Raman spectroscopy (SERS) has been widely used in efficiently detecting antibiotics because of its characteristics including fast response, high resolution, and strong resistance to moisture interference. However, as a core part of SERS technology, the design principle and detection performance of enhanced substrates used in monitoring antibiotics in dairy products have not yet received enough attention. Thus, it is necessary to give a critical review of the recent developments of SERS substrates for monitoring antibiotics in dairy products, which can be expected to provide inspiration for the efficient utilization of SERS technology. In this work, advances in various SERS substrates applied in sensing antibiotics in dairy products were comprehensively reviewed. First, the enhancement mechanisms were introduced in detail. Significantly, the types of enhanced materials (plasmonic metal particles [PMPs], PMPs/semiconductor composite materials) and biometric design strategies including immunoassay, aptamer, and molecularly imprinted polymers-based SERS biosensors applied in dairy products were systematically summarized for the first time. Meanwhile, the performance of SERS substrates used for the detection of antibiotics in dairy products was addressed from the aspects of dynamic linear range and detection restriction strategy. Finally, the conclusions, challenges, and future prospects of SERS substrates for antibiotic monitoring in dairy products were deeply discussed, which also provide new opinions and key points for constructing SERS substrates applied in complex food matrix in the future.

Diverse Dyes-Embedded Staphylococcus aureus as Potential Biocarriers for Enhancing Sensitivity in Biosensing.

Nanomaterials-based immunochromatographic assays (ICAs) have gained great commercial success in real-life point-of-care testing (POCT). Exploring novel carriers of ICAs with improved signaling and sustained activity favors the development of sensitive POCT. Herein a potent signal biotag, colored Staphylococcus aureus (SA), was created for ICA carriers through a mild self-assembly strategy, providing high luminance and abundant specific binding sites for immobilization of monoclonal antibodies (mAbs). The biocompatible SA-dyes (SADs) retained both an intact surface structure for mAbs labeling (Fc portion) and the superior bioactivity of immobilized mAbs (affinity constant was about 109 M-1), thus waiving the intrinsic limitations of traditional nanomaterials and endowing high sensitivity. Proof-of-concept was demonstrated by employing Congo red- or/and fluorescein isothiocyanate-embedded SA (SACR, SAFITC, and SACR-SAFITC) as ICA carriers to detect zearalenone (ZEN) through colorimetric or/and fluorimetric signals. Furthermore, the ICAs satisfied the clinical requirement perfectly, including limit of detection (0.013 ng/mL, which was at least an 85-fold improvement over that of traditional gold nanoparticles-based ICA), linearity (R2 > 0.98), reproducibility (RSD < 8%), selectivity, and stability. Importantly, the proposed biosensors could be well-applied in four real samples for ZEN monitoring with satisfactory recoveries, correlating well with the results from liquid chromatography-tandem mass spectrometry (LC-MS). This work also proved a universal design for tailoring coloration bands for SAD-ICA detection of multiple analytes.

Nicotine-derived NNK induces the stemness enrichment of CRC cells through regulating the balance of DUSP4-ERK1/2 feedback loop.

Cigarette smoking has been considered as an independent risk factor for colorectal cancer (CRC) initiation and progression. In this study, we found that cigarette smoking was significantly associated with poor CRC differentiation (P = 0.040). Since studies have indicated that poorly differentiated tumors are more aggressive and metastasize earlier, leading to poorer prognosis; and cancer stem cells (CSCs) are largely responsible for tumor differentiation state, here we observed that the exposure of nicotine-derived 4-(methylnitrosamino)- 1-(3-pyridyl)- 1-butanone (NNK) promoted cell sphere formation and the expression of the stem cell markers, CD44, OCT4, C-MYC and NANOG in HCT8 and DLD-1 cells. Further colony formation assay, CCK-8 assay and tumor-bearing experiment showed that NNK exposure significantly increased the proliferative and growth ability of CRC cells. In mechanism, we found that NNK-activated ERK1/2 played an important role in enrichment of CRC stem cells and the up-regulation of DUSP4, a major negative regulator of ERK1/2. Moreover, DUSP4 up-regulation was essential for maintaining NNK-activated ERK1/2 in an appropriate level, which was an required event for NNK-induced stemness enrichment of CRC cells. Taken together, our findings provided a possible mechanistic insight into cigarette smoking-induced CRC progression.

Dual-Emission Zr-MOF-Based Composite Material as a Fluorescence Turn-On Sensor for the Ultrasensitive Detection of Al3.

In this work, a novel zirconium-based metal-organic framework (MOF) composite material, UiO-(OH)2@RhB, has been solvothermally prepared with zirconyl chloride octahydrate, 2,5-dihydroxyterephthalic acid, and rhodamine B (RhB) for ratiometric fluorescence sensing of Al3+ ions in an aqueous medium. The luminescence measurement results showed that, at the single excitation wavelength of 420 nm, the fluorescence intensity of the ligand at 500 nm increased significantly in the case of Al3+, while that of RhB at 583 nm changed slightly, together with an apparent color change. Under optimal conditions, UiO-(OH)2@RhB exhibited an extraordinary sensitivity (10 nM), good selectivity, and a fast response (2 min) for Al3+. As far as we know, the limit of detection is superior to that of the current reported MOF-based Al3+ fluorescence sensors. The response mechanism suggested that -OH could capture Al3+ in water through coordination and high electrostatic affinity and achieved turn-on ratiometric fluorescence through the excited-state intramolecular proton transfer process and stable fluorescence of RhB. In addition, this sensor was also applied to actual food samples (grain beans), with the recoveries ranging from 89.08% to 113.61%. Such a turn-on ratiometric fluorescence sensor will provide a constructive strategy for the ultrasensitive detection of Al3+ in practical applications.

A screen printed carbon electrode modified with a lamellar nanocomposite containing dendritic silver nanostructures, reduced graphene oxide, and ß-cyclodextrin for voltammetric sensing of nitrite.

A disposable sensor is described for the determination of nitrite. A screen printed carbon electrode (SPCE) was modified with a 3D lamellar nanocomposite prepared by one-step electrodeposition from dendritic silver nanostructures, reduced graphene oxide, and ß-cyclodextrin. The modified SPCE exhibits high electrocatalytic activity toward nitrite oxidation, typically at a working potential at around 0.76 V (vs. Ag/AgCl). Sensitive and selective voltammetric detection of nitrite is demonstrated. The linear range extends from 1 to 2000 µM, the detection limit is 0.24 µM, and the sensitivity is 585.7 µA mM-1 cm-2. The method was applied to the determination of nitrite in (spiked) pickles. Graphical abstract Schematic presentation of fabrication of a screen printed carbon electrode modified with a lamellar nanocomposite containing dendritic silver nanostructures, reduced graphene oxide, and ß-cyclodextrin. Graphical abstract contains poor quality of text inside the artwork. Please do not re-use the file that we have rejected or attempt to increase its resolution and re-save. It is originally poor, therefore, increasing the resolution will not solve the quality problem. We suggest that you provide us the original format. We prefer replacement figures containing vector/editable objects rather than embedded images. Preferred file formats are eps, ai, tiff and pdf.We have provided the original format of graphical abstract in the attachment.

Carbon quantum dot-based fluorometric nitrite assay by exploiting the oxidation of iron(II) to iron(III).

The authors describe a simple and economical fluorescence method for the determination of nitrite by utilizing the fact that nitrite possesses strong oxidation in acidic solution and is capable to transform iron(II) into iron(III) ions. The latter quenches the fluorescence of carbon quantum dots (CQDs) based on the fluorescence static and dynamic quenching effect. The optimum reaction conditions and other analytical parameters are investigated to enhance the sensitivity of the method. At the excitation wavelength of 360 nm, this probe has a linear response in the 10 to 400 µM nitrite concentration range, with a correlation coefficient of R2 = 0.9958 (n = 3) and a detection limit of 0.48 µM. This method was successfully applied to the determination of nitrite in three different sausage samples and gave recoveries in the range between 101.8 to 103.0%, demonstrating the accuracy, reliability and potential application of this assay for monitoring nitrite. Graphical Abstract The carbon quantum dot/iron(II) ions system was used for the fluorometric detection of nitrite in food and environmental water. This probe exploits the oxidizing property of nitrite in acidic solution. Iron(II) is oxidized to iron(III) which exerts a strong fluorescence quenching effect.

A causal relationship between sarcopenia and cognitive impairment: A Mendelian randomization study.

OBJECTIVE: Sarcopenia and cognitive impairment often coexist in the elderly. In this study, we investigated the causal relationship between sarcopenia-related muscle characteristics and cognitive performance. METHODS: We used linkage disequilibrium score regression (LDSC) and Mendelian Randomization (MR) analyses to estimate genetic correlations and causal relationships between genetically predicted sarcopenia-related muscle traits and cognitive function, as well as cognitive function-based discovery samples and replicated samples. Estimated effect sizes were derived from a fixed-effects meta-analysis. RESULTS: Our univariate genome-wide association study (GWAS) meta-analysis indicated a causal relationship between appendicular lean mass (ALM) (ß = 0.049; 95% confidence interval (CI): 0.032-0.066, P < 0.001) and walking pace (ß = 0.349; 95% CI: 0.210-0.487, P < 0.001) with cognitive function, where a causal relationship existed between ALM in both male and female (ßALM-Male(M) = 0.060; 95% CI: 0.031-0.089, PALM-M < 0.001; ßALM-Female(F) = 0.045; 95% CI: 0.020-0.069, PALM-F < 0.001) with cognitive function. Low grip strength was not causally associated with cognitive function (ß = -0.045; 95% CI: -0.092 - -0.002, P = 0.062). A reverse causality GWAS meta-analysis showed a causal relationship between cognitive function and ALM (ß = 0.033; 95% CI: 0.018-0.048, P < 0.001) and walking pace (ß = 0.039; 95% CI: 0.033-0.051, P < 0.001), where ALM in both male and female showed a causality (ßALM-M = 0.041; 95% CI: 0.019-0.063, PALM-M < 0.001; ßALM-F = 0.034; 95% CI: 0.010-0.058, PALM-F = 0.005). Cognitive function was not causally related to low grip strength (ß = -0.024; 95% CI: -0.073-0.025, P = 0.344). Multivariable MR1 (MVMR1) analyses showed a significant causal relationship for ALM (ß = 0.077; 95% CI: 0.044-0.109, P = 0.000) and walking pace (ß = 0.579; 95% CI: 0.383-0.775, P = 0.000) and cognitive function. Multivariable MR2 (MVMR2) multivariate analysis showed that ALM causality remained (ß = 0.069; 95% CI: 0.033-0.106, P = 0.000), and walking pace (ß = 0.589; 95% CI: 0.372-0.806, P = 0.000). CONCLUSIONS: Bidirectional two-sample MR demonstrated that sarcopenia-related muscle characteristics and cognitive performance were positive causal genetic risk factors for each other, while a multivariable MR study demonstrated that low ALM and a slow walking pace were causally involved in reduced cognitive performance. This study suggests a causal relationship between sarcopenia and cognitive impairment in older adults and provide new ideas for prevention and treatment.

The demethylase ALKBH5 mediates ZKSCAN3 expression through the m6A modification to activate VEGFA transcription and thus participates in MNNG-induced gastric cancer progression.

N-Nitroso compounds (NOCs) are recognized as important factors that promote gastric cancer development, but the specific effects and potential mechanisms by which NOC exposure promotes gastric cancer are still poorly understood. In this study, we explored the effects and potential molecular mechanisms of NOCs on the promotion of gastric cancer using methylnitronitrosoguanidine (MNNG), a classical direct carcinogen of NOC. The results of in vivo and in vitro experiments showed that chronic and low-concentration MNNG exposure significantly promoted the malignant progression of tumors, including cell migration, cell invasion, vasculogenic mimicry (VM) formation, cell spheroid formation, stem cell-like marker expression, and gastric cancer growth and metastasis. Mechanistically, we revealed that demethylase ALKBH5 regulated the level of the N6­methyladenosine (m6A) modification in the 3'UTR and CDS region of the ZKSCAN3 mRNA to promote ZKSCAN3 expression, mediated the binding of ZKSCAN3 to the VEGFA promoter region to regulate VEGFA transcription, and participated in MNNG-induced gastric cancer cell migration, invasion, VM formation, cell spheroid formation, stem cell-like marker expression and ultimately gastric cancer progression. In addition, our study revealed that ALKBH5-ZKSCAN3-VEGFA signaling was significantly activated during MNNG-induced gastric carcinogenesis, and further studies in gastric cancer patients showed that ALKBH5, ZKSCAN3, and VEGFA expression were upregulated in cancers compared with paired gastric mucosal tissues, that ALKBH5, ZKSCAN3, and VEGFA could serve as important biomarkers for determining patient prognosis, and that the molecular combination showed greater prognostic value. These findings provide a theoretical basis for developing gastric cancer interventions for NOCs and for determining gastric cancer progression.

Circ_0000253 promotes the progression of osteosarcoma via the miR-1236-3p/SP1 axis.

OBJECTIVE: Circular RNAs (circRNAs) play important roles in modulating tumour progression. This study investigated the role of circ_0000253 in osteosarcoma (OS). METHODS: We downloaded the chip dataset GSE140256 from the Gene Expression Omnibus database and the circRNAs differentially expressed in OS tissue and normal tissue samples were analysed. Quantitative real-time PCR (qRT-PCR) was carried out to examine circ_0000253 expression in OS tissues and cells. Cell counting kit-8, BrdU and flow cytometry assays were performed to verify the effects of circ_0000253 on OS cell growth and apoptosis. Bioinformatics analysis was conducted to predict, and RNA immunoprecipitation assay and dual-luciferase reporter gene assay were performed to verify the targeted relationships of miR-1236-3p with circ_0000253 and Sp1 transcription factor (SP1) mRNA 3'UTR. The effects of miR-1236-3p and circ_0000253 on SP1 expression in OS cells were detected through Western blot. KEY FINDINGS: Circ_0000253 was upregulated in OS tissues and cell lines. Circ_0000253 overexpression facilitated OS cell growth and suppressed apoptosis, whereas knocking down circ_0000253 inhibited OS cell growth and facilitated apoptosis. Circ_0000253 targeted miR-1236-3p directly and negatively modulated its expression. SP1 was miR-1236-3p's target gene and positively regulated by circ_0000253. CONCLUSION: Circ_0000253 promotes OS cell proliferation and suppresses cell apoptosis via regulating the miR-1236-3p/SP1 molecular axis.

Electrochemical synthesis of Co/Ni bimetal-organic frameworks: A high-performance SERS platform for detection of tetracycline.

Surface-enhanced Raman scattering (SERS) enables food contaminants monitoring become facile and efficient. Herein, a facile strategy of integrating three-dimensional Ni form with Co/Ni bimetal-organic frameworks combining Ag nanoparticles via electrochemical synthesis method was proposed to develop a high-performance SERS substrate (CoNi-ZIFs@Ag@NF) for efficient detection of tetracycline. The flexible Ni foam (NF) acted as scaffold which can contribute to dramatically enhancing intrinsic electrical conductivity and endowing prepared substrate with high stability and uniform distribution of Ag nanoparticles. Furthermore, the pre-concentration effect of CoNi-ZIFs@Ag@NF for target molecules enhanced SERS performance dramatically. Besides, tetracycline was sensitively detected using CoNi-ZIFs@Ag@NF with low limit of detection (1.0 × 10-11 M) and wide linear detection range (10-10 - 10-5 M) in aqueous solution. Also, the satisfactory recovery (94.45 - 114.25 %) was realized with less than 6.78 % of RSD in real samples. This method would provide a potential and high-performance substrate for SERS monitoring of tetracycline in food and environment.

Daphnoretin relieves IL-1ß-mediated chondrocytes apoptosis via repressing endoplasmic reticulum stress and NLRP3 inflammasome.

BACKGROUND: Osteoarthritis (OA), mainly caused by severe joint degeneration, is often accompanied by joint pain and dysfunction syndrome. Inflammatory mediators and apoptosis play key roles in the evolution of OA. It is reported that daphnoretin has significant antiviral and anti-tumor values. The present study aims at investigating the role of daphnoretin in OA. METHODS: The OA mouse model was constructed by performing the destabilization of the medial meniscus through surgery, and the OA cell model was induced in ATDC5 chondrocytes with IL-1ß (10 ng/mL) in vitro. Chondrocyte viability and apoptosis were measured by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT), Caspase-3 activity, and flow cytometry. The levels of COX-2, iNOS, TNF-α, IL-6, Bax, Bcl2, cleaved-Caspase3, endoplasmic reticulum stress (ERS) proteins (GRP78, CHOP, ATF6, and Caspase-12), and NLRP3-ASC-Caspase1 inflammasome were determined by quantitative real-time PCR or western blot. The concentrations of TNF-α, IL-6, and PGE2 were tested by enzyme-linked immunosorbent assay. The content of nitrates was detected by the Griess method. In vivo, morphologic differences in knee joint sections and the thickness of the subchondral bone density plate in mice were observed by hematoxylin-eosin (H&E) staining and safranin O-fast green staining. RESULTS: Daphnoretin effectively choked IL-1ß-induced chondrocyte apoptosis and facilitated cell viability. Daphnoretin dose-dependently abated ERS, inflammatory mediators, and the activation of NLRP3 inflammasomes in IL-1ß-induced chondrocytes. What's more, in vivo experiments confirmed that daphnoretin alleviated OA progression in a murine OA model by mitigating inflammation and ERS. CONCLUSION: Daphnoretin alleviated IL-1ß-induced chondrocyte apoptosis by hindering ERS and NLRP3 inflammasome.

Highly selective and sensitive fluorescence detection of tetracyclines based on novel tungsten oxide quantum dots.

Tetracyclines (TCs) residues in animal products have attracted extensive concern due to their potential toxic to human health. Accordingly, it is urgent to develop an efficient method to determine TCs for providing consumers with risk pre-warning. Herein, a novel tungsten oxide quantum dots (WxOy QDs) fluorescence probe for tetracycline (TET) detection was constructed through ethanol-thermal method, which exhibited intense blue fluorescence under 365 nm UV light. Interestingly, blue-emitting WxOy QDs could be quenched obviously after the addition of TET, which may be attributed to the synergism of inner filter effect (IFE), fluorescence resonance energy transfer (FRET) and photo-induced electron transfer (PET). Thereby, the fluorescence method was established for TET detection based on WxOy QDs. Additionally, the presented method was demonstrated by monitoring TET in milk and milk powder with satisfactory recoveries. More importantly, this work offered good demonstration for the detection of food hazard factors.

Identification and validation of a cigarette smoke-related five-gene signature as a prognostic biomarker in kidney renal clear cell carcinoma.

Cigarette smoking greatly promotes the progression of kidney renal clear cell carcinoma (KIRC), however, the underlying molecular events has not been fully established. In this study, RCC cells were exposed to the tobacco specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK, nicotine-derived nitrosamine) for 120 days (40 passages), and then the soft agar colony formation, wound healing and transwell assays were used to explore characteristics of RCC cells. RNA-seq was used to explore differentially expressed genes. We found that NNK promoted RCC cell growth and migration in a dose-dependent manner, and RNA-seq explored 14 differentially expressed genes. In TCGA-KIRC cohort, Lasso regression and multivariate COX regression models screened and constructed a five-gene signature containing ANKRD1, CYB5A, ECHDC3, MT1E, and AKT1S1. This novel gene signature significantly associated with TNM stage, invasion depth, metastasis, and tumor grade. Moreover, when compared with individual genes, the gene signature contained a higher hazard ratio and therefore had a more powerful value for the prognosis of KIRC. A nomogram was also developed based on clinical features and the gene signature, which showed good application. Finally, AKT1S1, the most crucial component of the gene signature, was significantly induced after NNK exposure and its related AKT/mTOR signaling pathway was dramatically activated. Our findings supported that NNK exposure would promote the KIRC progression, and the novel cigarette smoke-related five-gene signature might serve as a highly efficient biomarker to identify progression of KIRC patients, AKT1S1 might play an important role in cigarette smoke exposure-induced KIRC progression.

NiCu nanoalloy embedded in N-doped porous carbon composite as superior electrochemical sensor for neonicotinoid determination.

Enhancing catalytic activity is the key to develop electrochemical sensors for monitoring of neonicotinoid such as imidacloprid (IMI), thiamethoxam (THX) and dinotefuran (DNF). Herein, a MOF-derived octahedral NiCu nanoporous carbon composite with abundant N-doped (N/NiCu@C) was synthesized, which was exploited as electrochemical sensor for neonicotinoid determination. Integrating the synergistic effect of NiCu nanoalloy and the hierarchical porous carbon structure, the N/NiCu@C/GCE significantly promoted the diffusion between electrolyte and active site. Meanwhile, the introduction of polyvinylpyrrolidone (PVP) improved the hydrophilicity and dispersibility of N/NiCu@C, endowing superior electrocatalytic performance for IMI, THX and DNF determination, with linear ranges of 0.5-60, 1-60 and 0.5-60 µM, respectively, and detection limits of 0.017, 0.007 and 0.001 µM. Additionally, the sensor can determine IMI, THX and DNF in apples, tomatoes and potatoes with the recovery rate of 92.1-103.4% and RSD ≤ 4.7%. This study has explored a novel modified electrode material for construction of neonicotinoid sensors.

ING4 Promotes Stemness Enrichment of Human Renal Cell Carcinoma Cells Through Inhibiting DUSP4 Expression to Activate the p38 MAPK/type I IFN-Stimulated Gene Signaling Pathway.

Renal cell carcinoma (RCC) recurs frequently due to high metastatic spread, resulting in a high mortality. Cancer stem cells play a critical role in initiating the tumor metastasis. Inhibitor of growth 4 (ING4) is a member of the ING family, but its impact on cancer stem cells in RCC is still unknown. In this study, we found that ING4 significantly promoted the sphere-forming size and number of RCC cells under an ultralow-attachment culture condition in vitro, tumor growth and metastasis in vivo, and the expression of some stem-like or pluripotent biomarkers CD44, MYC, OCT4, and NANOG, indicating that ING4 increased the stemness enrichment of RCC cells. Mechanistically, the ING4-activated p38 MAPK pathway possibly upregulated the expression of type I IFN-stimulated genes to promote the formation of RCC stem cells. ING4 could inhibit the expression of DUSP4 to activate p38 MAPK. In addition, selective pharmacological p38 MAPK inhibitors could significantly inhibit stemness enrichment only in ING4-overexpressed RCC cells, suggesting that the p38 MAPK inhibitors might be effective in patients with high ING4 expression in RCC tissue. Taken together, our findings proposed that ING4 might serve as a potential therapeutic target for metastatic RCC, particularly RCC stem cells.

Surface Selenylation Engineering for Construction of a Hierarchical NiSe2/Carbon Nanorod: A High-Performance Nonenzymatic Glucose Sensor.

As glucose (Glu) is an essential substance for metabolism as well as a symbol to diagnose diabetes, the demand of Glu sensors has increased significantly in recent decades. In this work, a hierarchical Ni-based electrochemical enzyme-free Glu sensor, namely, NiSe2/CNR (carbon nanorod), was engineered through a facile thermal treatment using dimethylglyoxime dinickel salt with selenium (Se) powder. The prepared NiSe2/CNR not only subtly introduces a hierarchical structure with rod-like carbon nanorods and rock-like NiSe2 nanoparticles, which are extremely helpful in offering a greater catalytic activity area and more catalytic active sites, but also incorporates the Se element to increase the inherent activity. The fabricated NiSe2/CNR exhibits distinguished performance for Glu detection in alkaline electrolytes with linear ranges of 0.5-411 µM and 411 µM to 6.311 mM, high sensitivities of 3636 µA mM-1 cm-2 at low concentrations, and 2121 µA mM-1 cm-2 at high concentrations, as well as a low detection limit of 380 nM (S/N = 3). It also possesses favorable reproducibility, stability, and long-term storage capacity. The practical feasibility of NiSe2/CNR was also validated by detecting Glu in human serum. Moreover, the prepared hierarchical NiSe2/CNR is of general interest for the construction of hierarchical Ni-based sensors.

Carbon cloth-supported nanorod-like conductive Ni/Co bimetal MOF: A stable and high-performance enzyme-free electrochemical sensor for determination of glucose in serum and beverage.

In this work, we propose a electrochemical enzyme-free glucose sensor by direct growth of conductive Ni/Co bimetal MOF on carbon cloth [Ni/Co(HHTP)MOF/CC] via a facile hydrothermal method. Due to excellent conductivity between Ni/Co(HHTP)MOF and CC, synergic catalytic effect of Ni and Co elements, the Ni/Co(HHTP)MOF/CC not only provides larger surface area and more effective active sites, but also boosts the charge transports and electro-catalytic performance. Under optimized conditions, the Ni/Co(HHTP)MOF/CC shows excellent activity with a linear range of 0.3 µM-2.312 mM, a low detection limit of 100 nM (S/N = 3), a fast response time of 2 s and a high sensitivity of 3250 µA mM-1 cm-2. Furthermore, the Ni/Co(HHTP)MOF/CC was successfully applied for the detection of glucose in real serum and beverages with competitive performances. This facile and cost-effective method provides a novel strategy for monitoring of glucose in biological and food samples.

Nitrogen, silicon co-doped carbon dots as the fluorescence nanoprobe for trace p-nitrophenol detection based on inner filter effect.

P-nitrophenol (PNP) has been widely applied to industry processing for many purposes, but the persistence and toxicity of residuum may pose risks to human health. To analyze PNP in industrial and agricultural wastewater, a versatile fluorescent probe sensing platform was proposed. In this work, we devised a fluorescence approach that utilized nitrogen, silicon co-doped carbon dots (N,Si-CDs) to monitor PNP originating from the inner filter effect (IFE). The N,Si-CDs were generated in a one-step hydrothermal synthesis, and which possessed outstanding fluorescence signal and water-dispersity. Emission at 441 nm was monitored with excitation at 360 nm using a common spectrofluorometer. The method achieved an exceptionally low limit of detection (LOD) of 0.011 µM. Furthermore, this method not only eliminates the interference from metal ions and acid ions, but also provides a potential application prospect for N,Si-CDs in the field of water monitoring. Analysis of tap and lake water led to 93.30-106.30% recoveries and <1% relative standard deviation at 2.5-25 µM PNP concentrations.

Multifunctional bacteria-derived tags for advancing immunoassay analytical performance with dual-channel switching and antibodies bioactivity sustaining.

Constructing multifunctional immunochromatographic assays (ICA) carriers with multiple signals and retaining bioactivity of monoclonal antibodies (mAbs) are conducive to the sensitive and accurate point-of-care testing (POCT). To fulfill this pressing need, a microorganism-based microsphere mediated dual-modal ICA (DICA) was developed for sensitive and reliable detection of zearalenone (ZEN). As the key to the biosensor, a superb biotag with an intact coccus morphology was designed based on Staphylococcus aureus biosynthesized quantum dots incorporating Ru(bpy)32+ (SAQDsRu), in which SA offered a specific recognition capacity for Fc region of mAbs, QDs endowed a naked-eye discernible colorimetric signal on the SA, and robust fluorescence signal that remedied for the insufficient brightness of QDs was derived from Ru(bpy)32+. The characterization of SAQDsRu-labeled mAb (SAQDsRu-mAb) probe demonstrated strong luminescence, excellent stability and high affinity with ZEN (affinity constant was approximately 1.723 × 109 M-1), which can significantly improve the detection sensitivity. Impressively, a portable sensing system was developed by the integration of SAQDsRu-DICA with a smartphone-based readout. After optimization, this DICA indicated a limit of detection reaching down to 0.008 ng/mL (colorimetric mode) and 0.0058 ng/mL (fluorescent mode), which were much lower than that of conventional gold nanoparticles-based ICA (0.1029 ng/mL), possessing favorable specificity and repeatability (relative standard deviation (RSD) < 10%). Moreover, the feasibility of the immunoassay was further assessed by measuring ZEN in real samples with satisfactory recoveries, and the results are good consistent with liquid chromatography tandem mass spectrometry (LC-MS/MS).

Construction of a photothermal hydrogel platform with two-dimensional PEG@zirconium-ferrocene MOF nanozymes for rapid tissue repair of bacteria-infected wounds.

Because of increasing antibiotic resistance, careful construction of an efficient phototherm-nanozyme-hydrogel synergistic antibacterial platform is imperative for the treatment of bacteria-infected wounds. In this study, a carrageenan-based hydrogel embedded with polyethylene glycol dicarboxylic acid (COOH-PEG-COOH)-functionalized zirconium-ferrocene metal-organic frames nanosheets (PEG@Zr-Fc MOF hydrogel) was successfully constructed through COOH-PEG-COOH modification and physical assembly. The PEG@Zr-Fc MOF hydrogel could capture Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria through reactive oxygen species (ROS) destruction and kill some bacteria by disintegration of H2O2 into toxic hydroxyl radicals (•OH). Significantly, by introducing the photothermal performance of the PEG@Zr-Fc MOF hydrogel, the catalytic activity of the target material could be improved to achieve a synergistic sterilization effect. The wound infection model experiment confirmed that the PEG@Zr-Fc MOF hydrogel had powerful bactericidal activity and could achieve a rapid tissue repair effect. More importantly, the PEG@Zr-Fc MOF hydrogel had negligible biological toxicity and reduced the risk of inflammation. This study reveals that phototherm-nanozyme-hydrogel synergy holds great potential for bacterial wound infection therapy. Additionally, this is the first study to use two-dimensional MOF nanozymes in combination with hydrogel for antimicrobial therapy. STATEMENT OF SIGNIFICANCE: Bacteria-infected wound is one of the serious threats to public health, and this topic has attracted tremendous attention worldwide in recent decades. Although numerous traditional therapeutic strategies that depend on antibiotics have been developed and applied for treating bacteria-infected wound disease, the effect of wound treatment is becoming increasingly unsatisfactory due to bacterial resistance. The present study provides a feasible method to treat bacterial wound infection by constructing a carrageenan-based hydrogel embedded with polyethylene glycol dicarboxylic acid (COOH-PEG-COOH) functionalized zirconium-ferrocene metal organic frame nanosheets (PEG@Zr-Fc MOF hydrogel). The experiments with the wound infection model confirmed that the PEG@Zr-Fc MOF hydrogel had powerful bactericidal activity and could achieve a rapid tissue repair. This strategy provides a promising avenue to further accelerate the development of antibacterial therapy in biomedical fields.