Stem cell-derived exosomes for traumatic spinal cord injury: a systematic review and network meta-analysis based on a rat model.

BACKGROUND AIMS: Exosome therapy for traumatic spinal cord injury (TSCI) is a current research hotspot, but its therapeutic effect and the best source of stem cells for exosomes are unclear. METHODS: The Web of Science, PubMed, Embase, Cochrane, and Scopus databases were searched from inception to March 28, 2023. Literature screening, data extraction and risk of bias assessment were performed independently by two investigators. RESULTS: A total of 40 studies were included for data analysis. The findings of our traditional meta-analysis indicate that exosomes derived from stem cells significantly improve the motor function of TSCI at various time points (1 week: weighted mean difference [WMD] = 1.58, 95% confidence interval [CI] 0.87-2.30] 2 weeks: WMD = 3.12, 95% CI 2.64-3.61; 3 weeks: WMD = 4.44, 95% CI 3.27-5.60; 4 weeks: WMD = 4.54, 95% CI 3.42-5.66). Four kinds of stem cell-derived exosomes have been studied: bone marrow mesenchymal stem cells, adipose mesenchymal stem cells, umbilical cord mesenchymal stem cells and neural stem cells. The results of the network meta-analysis showed that there was no significant statistical difference in the therapeutic effect among the exosomes derived from four kinds of stem cells at different treatment time points. Although exosomes derived from bone marrow mesenchymal stem cells are the current research focus, exosomes derived from neural stem cells have the most therapeutic potential and should become the focus of future attention. CONCLUSIONS: The exosomes derived from stem cells can significantly improve the motor function of TSCI rats, and the exosomes derived from neural stem cells have the most therapeutic potential. However, the lower evidence quality of animal studies limits the reliability of experimental results, emphasizing the need for more high-quality, direct comparative studies to explore the therapeutic efficacy of exosomes and the best source of stem cells.

Quasi-Solid-State All-V2 O5 Battery.

Solid-state symmetrical battery represents a promising paradigm for future battery technology. However, its development is hindered by the deficiency of high-performance bipolar electrodes and compatible solid electrolytes. Herein, a quasi-solid-state all-V2 O5 battery constructed by a binder-free carbon fabric-V2 O5 nanowires@graphene (CVOG) bipolar electrode and a softly cross-linked polyethylene oxide-based solid polymer electrolyte (SPE) is reported. The synergetic effect of nano-structuring of V2 O5 , hierarchical conductive network, and graphene wrapping endows the CVOG electrode with boosted reaction kinetics and suppressed vanadium dissolution. The cathodic and anodic reactions of CVOG are decoupled by electrochemical analysis, conceiving the feasibility of constructing all-V2 O5 full battery. In manifesting the solid-state all-V2 O5 battery, the robust and elastic SPE exhibits high ionic conductivity, tight/self-adaptable electrolyte-electrode contact, and a low charge-transfer barrier. The resultant solid-state full battery exhibits a high reversible capacity of 158 mAh g-1 at 0.1 C, good capacity retention of over 61% from 0.1 C to 2 C, and remarkable cycling stability of 77% capacity retention after 1000 cycles at 1 C, which surpass other solid-state symmetrical batteries. Hence, this work provides a practice of high-performance solid-state batteries with symmetrical configuration and is constructive for next-generation battery technology.

The effects of Shikonin on the hypertrophic scar of rabbit ears via the TLR4/NF-κB signaling pathway.

As a traditional Chinese medicine, Zihuang Shengji Ointment has obvious effects on promoting postoperative wound healing and reducing scar formation in clinical application. Shikonin is the major phytochemical in Zihuang Shengji Ointment. As a kind of naphquinone compound with anti-tumor, anti-viral, anti-inflammatory, anti-bacterial and other biological activities extracted from Lithospermum erythrorhizon, shikonin exerts an important role in many diseases. Shikonin has impacts on the development of hypertrophic scars (HS), however, these effects are yet mostly unknown. As a result, we created the Newland white rabbit ear HS model, administered shikonin to it, and then assessed scar hypertrophy using HE and VG staining. The degree of scarring is assessed by HI, NA, as well as AA. The expression levels of collagen I, collagen III, as well as α-SMA as well as fibroblast proliferation, are also measured using real-time PCR, immunohistochemistry, and western blot. TUNEL tests are used to assess fibroblast apoptosis. In our work, HE staining and VG staining showed that the shikonin-treated group had normal bundles of collagen fibers and regular fibroblasts. Shikonin suppresses the production of HS, according to histopathological features, HI, NA, and AA measures. Shikonin also causes fibroblast apoptosis and lowers the production of α-SMA, collagen I, as well as collagen III in the HS rat. Notably, we discover that NF-κB activation and TLR4 activity are inhibited by shikonin. Overall, the results show that the signaling pathway of TLR4/NF-κB is modulated by shikonin's inhibitory effect on scar formation, which represses the levels of collagen I, collagen III, α-SMA, as well as fibroblasts.

Bibliometric analysis of stem cells for spinal cord injury: current status and emerging frontiers.

Background: This study aimed to conduct a bibliometric analysis of the literature on stem cell therapy for spinal cord injury to visualize the research status, identify hotspots, and explore the development trends in this field. Methods: We searched the Web of Science Core Collection database using relevant keywords ("stem cells" and "spinal cord injury") and retrieved the published literature between 2000 and 2022. Data such as journal title, author information, institutional affiliation, country, and keywords were extracted. Afterwards, we performed bibliometric analysis of the retrieved data using Bibliometrix, VOSviewer, and CiteSpace. Results: A total of 5375 articles related to stem cell therapy for spinal cord injury were retrieved, and both the annual publication volume and the cumulative publication volume showed an upward trend. neural regeneration research was the journal with the most publications and the fastest cumulative publication growth (162 articles), Okano Hideyuki was the author with the highest number of publications and citations (114 articles), Sun Yat-sen University was the institution with the highest number of publications (420 articles), and China was the country with the highest number of publications (5357 articles). However, different authors, institutions, and countries need to enhance their cooperation in order to promote the generation of significant academic achievements. Current research in this field has focused on stem cell transplantation, neural regeneration, motor function recovery, exosomes, and tissue engineering. Meanwhile, future research directions are primarily concerned with the molecular mechanisms, safety, clinical trials, exosomes, scaffolds, hydrogels, and inflammatory responses of stem cell therapy for spinal cord injuries. Conclusion: In summary, this study provided a comprehensive analysis of the current research status and frontiers of stem cell therapy for spinal cord injury. The findings provide a foundation for future research and clinical translation efforts of stem cell therapy in this field.

An injectable, self-healing, electroconductive hydrogel loaded with neural stem cells and donepezil for enhancing local therapy effect of spinal cord injury.

BACKGROUND: Spinal cord injury (SCI) is a serious injury with high mortality and disability rates, and there is no effective treatment at present. It has been reported that some treatments, such as drug intervention and stem cell transplantation have positive effects in promoting neurological recovery. Although those treatments are effective for nerve regeneration, many drawbacks, such as low stem cell survival rates and side effects caused by systemic medication, have limited their development. In recent years, injectable hydrogel materials have been widely used in tissue engineering due to their good biocompatibility, biodegradability, controllable properties, and low invasiveness. The treatment strategy of injectable hydrogels combined with stem cells or drugs has made some progress in SCI repair, showing the potential to overcome the drawbacks of traditional drugs and stem cell therapy. METHODS: In this study, a novel injectable electroactive hydrogel (NGP) based on sodium hyaluronate oxide (SAO) and polyaniline-grafted gelatine (NH2-Gel-PANI) was developed as a material in which to load neural stem cells (NSCs) and donepezil (DPL) to facilitate nerve regeneration after SCI. To evaluate the potential of the prepared NGP hydrogel in SCI repair applications, the surface morphology, self-repairing properties, electrical conductivity and cytocompatibility of the resulting hydrogel were analysed. Meanwhile, we evaluated the neural repair ability of NGP hydrogels loaded with DPL and NSCs using a rat model of spinal cord injury. RESULTS: The NGP hydrogel has a suitable pore size, good biocompatibility, excellent conductivity, and injectable and self-repairing properties, and its degradation rate matches the repair cycle of spinal cord injury. In addition, DPL could be released continuously and slowly from the NGP hydrogel; thus, the NGP hydrogel could serve as an excellent carrier for drugs and cells. The results of in vitro cell experiments showed that the NGP hydrogel had good cytocompatibility and could significantly promote the neuronal differentiation and axon growth of NSCs, and loading the hydrogel with DPL could significantly enhance this effect. More importantly, the NGP hydrogel loaded with DPL showed a significant inhibitory effect on astrocytic differentiation of NSCs in vitro. Animal experiments showed that the combination of NGP hydrogel, DPL, and NSCs had the best therapeutic effect on the recovery of motor function and nerve conduction function in rats. NGP hydrogel loaded with NSCs and DPL not only significantly increased the myelin sheath area, number of new neurons and axon area but also minimized the area of the cystic cavity and glial scar and promoted neural circuit reconstruction. CONCLUSIONS: The DPL- and NSC-laden electroactive hydrogel developed in this study is an ideal biomaterial for the treatment of traumatic spinal cord injury.

Delay in seeking health care from community residents during a time with low prevalence of COVID-19: A cross-sectional national survey in China.

Background: The pandemic of COVID-19 has significant implications on health resources allocation and health care delivery. Patients with non-COVID illness may have to change their care seeking behaviors to mitigate the risk of infections. The research aimed to investigate potential delay of community residents in seeking health care at a time with an overall low prevalence of COVID-19 in China. Methods: An online survey was conducted in March 2021 on a random sample drawn from the registered survey participants of the survey platform Wenjuanxing. The respondents who reported a need for health care over the past month (n = 1,317) were asked to report their health care experiences and concerns. Logistic regression models were established to identify predictors of the delay in seeking health care. The selection of independent variables was guided by the Andersen's service utilization model. All data analyses were performed using SPSS 23.0. A two-sided p value of <0.05 was considered as statistically significant. Key results: About 31.4% of respondents reported delay in seeking health care, with fear of infection (53.5%) as a top reason. Middle (31-59 years) age (AOR = 1.535; 95% CI, 1.132 to 2.246), lower levels of perceived controllability of COVID-19 (AOR = 1.591; 95% CI 1.187 to 2.131), living with chronic conditions (AOR = 2.008; 95% CI 1.544 to 2.611), pregnancy or co-habiting with a pregnant woman (AOR = 2.115; 95% CI 1.154 to 3.874), access to Internet-based medical care (AOR = 2.529; 95% CI 1.960 to 3.265), and higher risk level of the region (AOR = 1.736; 95% CI 1.307 to 2.334) were significant predictors of the delay in seeking health care after adjustment for variations of other variables. Medical consultations (38.7%), emergency treatment (18.2%), and obtainment of medicines (16.5%) were the top three types of delayed care, while eye, nose, and throat diseases (23.2%) and cardiovascular and cerebrovascular diseases (20.8%) were the top two conditions relating to the delayed care. Self-treatment at home was the most likely coping strategy (34.9%), followed by Internet-based medical care (29.2%) and family/friend help (24.0%). Conclusions: Delay in seeking health care remained at a relatively high level when the number of new COVID-19 cases was low, which may present a serious health risk to the patients, in particular those living with chronic conditions who need continuous medical care. Fear of infection is the top reason for the delay. The delay is also associated with access to Internet-based medical care, living in a high risk region, and perceived low controllability of COVID-19.

Influence of Oxygen Management during the Post-Fermentation Stage on Acetaldehyde, Color, and Phenolics of Vitis vinifera L. Cv. Cabernet Sauvignon Wine.

Oxygen exposure is unavoidable and the impact of its management during the post-fermentation stage (PFS) on dry red wine is poorly investigated. This study was dedicated to the variation of acetaldehyde, color and phenolics of Cabernet Sauvignon dry red wine during five discontinuous oxidation cycles of four levels of controlled oxygen supply, which were carried out to simulate probable oxidation during the PFS. Free SO2 disappeared after the first, second and third oxidation cycles in wines with high, medium and low levels of oxygen exposure severally, but subsequent oxygen exposure below or equal to 2 mg O2/L per cycle had little effect while 3-3.9 mg O2/L per cycle dramatically facilitated acetaldehyde accumulation, which was accompanied by an enormous variation in color and pigments, especially when total oxygen consumption was above 10 mg/L. The utilization of clustered heatmap and partial least square regression demonstrated the feasibility of characterization of wine oxidation degree using the chemical parameters measured by UV-spectrophotometry. Oxygen exposure during the PFS should be emphatically controlled, and chemical indexes determined by the UV-spectrophotometric method can be used for a scientific and effective description of wine oxidation degree.

Impact of the Acetaldehyde-Mediated Condensation on the Phenolic Composition and Antioxidant Activity of Vitis vinifera L. Cv. Merlot Wine.

Acetaldehyde is a critical reactant on modifying the phenolic profile during red wine aging, suggesting that the acetaldehyde-mediated condensation can be responsible for the variation of antioxidant activity during the aging of this beverage. The present study employs exogenous acetaldehyde at six levels of treatment (7.86 ± 0.10-259.02 ± 4.95 mg/L) before the bottle aging of Merlot wines to encourage phenolic modification. Acetaldehyde and antioxidant activity of wine were evaluated at 0, 15, 30, 45, 60 and 75 days of storage, while monomeric and polymeric phenolics were analyzed at 0, 30 and 75 days of storage. The loss of acetaldehyde was fitted to a first-order reaction model, the rate constant (k) demonstrated that different chemical reaction happened in wines containing a different initial acetaldehyde. The disappearance of monomeric phenolics and the formation of polymeric phenolics induced by acetaldehyde could be divided into two phases, the antioxidant activity of wine did not alter significantly in the first phase, although most monomeric phenolics vanished, but the second phase would dramatically reduce the antioxidant activity of wine. Furthermore, a higher level of acetaldehyde could shorten the reaction time of the first phase. These results indicate that careful vinification handling aiming at controlling the acetaldehyde allows one to maintain prolonged biological activity during wine aging.

Colorimetric determination of cysteine based on Au@Pt nanoparticles as oxidase mimetics with enhanced selectivity.

A H2O2-free colorimetric protocol based on urchin-like Au@Pt nanoparticles (Au@Pt NPs) has been developed for the sensitive and selective determination of cysteine (Cys). We verified the intrinsic oxidase-like activity of the Au@Pt NPs. They can act as artificial mimic oxidases to catalyse the oxidization of 3,3',5,5'-tetramethylbenzidine (TMB) with the assistance of dissolved oxygen, avoiding the use of H2O2 in the colorimetric determination of Cys. In addition, the discrimination of Cys from the other two biothiol analogues, homocysteine and glutathione, can be easily realized through a simple ageing process. HNO3 is added to this colorimetric system to terminate the reaction by oxidizing ox-TMB (oxidized form of TMB) to diphenoquinone (DPQ), thus generating a characteristic absorption peak of DPQ at 450 nm. By recording the absorbance at 450 nm, interference from the aggregated Au@Pt NPs (absorption peak at 670 nm) when 650 nm (the characteristic absorption peak of ox-TMB) is used as the absorption wavelength can be eliminated. We investigated this H2O2-free colorimetric protocol and obtained high sensitivity, with a detection limit of 1.5 nM and relatively high selectivity. The analytical performance for real samples was further explored. The Au@Pt NP-based H2O2-free colorimetric protocol is of great significance for the sensitive and selective determination of Cys in practical samples in different scenarios.

RETRACTED: Exosomal microRNA-16-5p from adipose mesenchymal stem cells promotes TLR4-mediated M2 macrophage polarization in septic lung injury.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). The authors have requested that this paper be retracted as they were unable to replicate the experimental data reported in Figure 1A. The authors posit that changes in reagents or experimental conditions might be the source of their inability to do so. Additional concerns were raised about the reliability of the Western blot results in Figure 1E, Figure 4B and F, Figure 5B, and Figure 6B, as regarding 'morphology space' similarities contained within a series of papers with distinctive eyebrow blots, tabulated here (https://docs.google.com/spreadsheets/d/149EjFXVxpwkBXYJOnOHb6RhAqT4a2llhj9LM60MBffM/edit#gid=0 [nam11.safelinks.protection.outlook.com] [nam11.safelinks.protection.outlook.com]). The journal requested the authors comment on these concerns and provide raw data. However, the authors were not able to fulfil this request and therefore the Editor-in-Chief decided to retract the article.

A Fast Dual-responsive OFF-ON Fluorescent Probe for Cysteine and Glutathione without Interference from Homocysteine.

Abnormal levels of biothiols, such as cysteine (Cys), homocystine (Hcy), and glutathione (GSH), are generally known to result in various diseases. A fast dual-responsive OFF-ON fluorescent probe HBO-AC was synthesized and developed. Non-fluorescent HBO-AC can sense Cys by regaining fluorescence at 444 nm within 10 min and a response to GSH by restoring fluorescence at 349 nm within 20 min. There is no mutual interference with Δλ ca. 100 nm. A novel method was developed by utilizing a low reaction rate between HBO-AC and Hcy to eliminate common interference from Hcy. A successful determination of Cys and GSH in fetal bovine serum (FBS) indicated that the probe had potential application for clinical diagnosis. Moreover, it was confirmed that HBO-AC can resist interference from protein to some extent, since FBS was not pretreated before use.

A colorimetric sensor for detecting thiourea based on inhibiting peroxidase-like activity of gold-platinum nanoparticles.

In this study, gold-platinum nanoparticles (Au@PtNPs) with peroxidase-like activity were synthesized. In the absence of thiourea (TU), the Au@PtNPs can catalyze the decomposition of hydrogen peroxide, and oxidize 3,3',5,5'-tetramethylbenzidine dihydrochloride (TMB, colorless) into oxidized 3,3',5,5'-tetramethylbenzidine dihydrochloride (oxTMB, blue). The peroxidase-like activity of the Au@PtNPs is inhibited in the presence of TU, and TMB cannot be oxidized to oxTMB effectively, and no blue color could be observed. Based on this finding, a novel colorimetric sensor for detecting TU is proposed. The absorbance response curve showed a good linearity for the concentration of TU in the range of 10 nmol L-1 to 10 µmol L-1 with a correlation coefficient of R2 = 0.999, and the limit of detection is 9.57 nmol L-1. The colorimetric sensor possesses excellent selectivity, anti-interference ability, and application value in actual samples.

Composition, physicochemical properties, and anti-fatigue activity of water-soluble okra (Abelmoschus esculentus) stem pectins.

Okra, Abelmoschus esculentus (L.) Moench, an annual herbaceous plant, is widely distributed in tropical and subtropical regions. Water-soluble pectic hydrocolloids from okra stems (HOS) were extracted and purified using polydivinylbenzene HP-20 resins. The sugar composition of the purified HOS with an weight-average molecular weight of 178.4 ± 2.1 kDa and a polydispersity index of 1.02 ± 0.02 contained galacturonic acid (34%), galactose (31%), rhamnose (21%), arabinose (4.2%), glucuronic acid (2.5%), xylose (1.2%), and other monosaccharides (6.1%) by weight. Its favorable rheological behaviors were evident on relatively higher concentrations (20, 25, and 30 mg/mL) and moderately lower pH levels (3 and 5) of HOS. The anti-fatigue experiments in vivo demonstrated that a high dose of HOS (450 mg/kg feed) prolonged the exhaustive swimming time of mice, significantly induced an increase in blood glucose and glycogen, and decreased lactic acid and serum urea nitrogen levels. HOS digestion in vivo was fairly conducive to the improvement of energy storage capacity and renal function for physically induced fatigue, compared with the conventional herbal supplement Panax quinquefolium. Accordingly, HOS exhibits potential for reutilization of okra stem waste.

Upregulated lncRNA Pvt1 may be important for cardiac remodeling at the infarct border zone.

Myocardial infarction (MI) is a leading cause of mortality due to progression to ventricular arrhythmias (VAs) or heart failure (HF). Cardiac remodeling at the infarct border zone (IBZ) is the primary contributor for VAs or HF. Therefore, genes involved in IBZ remodeling may be potential targets for the treatment of MI, but the mechanism remains unclear. The present study aimed to explain the molecular mechanisms of IBZ remodeling based on the roles of long non­coding RNAs (lncRNAs). After downloading miRNA (GSE76592) and mRNA/lncRNA (GSE52313) datasets from the Gene Expression Omnibus database, 23 differentially expressed miRNAs (DEMs), 2,563 genes (DEGs) and 168 lncRNAs (DELs) were identified between IBZ samples of MI mice and sham controls. A total of 483 DEGs were predicted to be regulated by 23 DEMs, among which Itgam, Met and TNF belonged to hub genes after five topological parameters were calculated for genes in the protein­protein interaction network. These hub genes­associated DEMs (mmu­miR­181a, mmu­miR­762) can also interact with six DELs (Gm15832, Gas5, Gm6634, Pvt1, Gm14636 and A330023F24Rik) to constitute the competing endogenous RNA (ceRNA) axes. Furthermore, a co­expression network was constructed based on the co­expression pairs between 44 DELs and 297 DEGs, in which Pvt1 and Bst1 were overlapped with the ceRNA network. Thus, Bst1­associated ceRNA (Pvt1­mmu­miR­181a­Bst1) and co­expression (Pvt­Bst1) axes were also pivotal for MI. Accordingly, Pvt1 may be a crucial lncRNA for modification of cardiac remodeling in the IBZ after MI and may function by acting as a ceRNA for miR­181a to regulate TNF/Met/Itgam/Bst1 or by co­expressing with Bst1.

Solution-Processed All-V2 O5 Battery.

Exploring new battery technologies will promote the advance of energy storage systems. Designing a symmetrical-structured rechargeable battery with the same electrode materials is a meaningful exploration for battery technology. Here, a solution-processed all-V2 O5 rechargeable battery with V2 O5 as both anode and cathode is presented, in which the anionic/cationic redox reactions are decoupled by precisely clamping its working potential windows. The battery shows good electrochemical performance with high capacity of 151 mAh g-1 at 0.10 C, good rate performance with 70% capacity retention when the current increases from 0.10 to 5 C, and promising cycling stability over 83% capacity retention after 900 cycles at 1 C. Moreover, the battery is highly profitable for simplified fabrication and scalable production, which benefits from its symmetrical configuration as well as the solution-processed strategy. This work offers a new paradigm to construct advanced symmetrical energy storage devices.

A turn-on fluorescent probe based on quinoline and coumarin for rapid, selective and sensitive detection of hypochlorite in water samples.

A fluorescent probe L-Cu2+ based on quinoline, coumarin and Cu2+ has been synthesized and characterized for hypochlorite determination. After copper ion was added to the solution of ligand L, the fluorescence quenching at 490 nm might result from a ligand-metal charge transfer (LMCT) process and its strong coordination ability for Cu2+ . In the presence of hypochlorite, the structure of ligand L was destroyed to form 7-(diethylamino)-coumarin-3-carboxylic acid, and the fluorescence was restored at 460 nm. In this case, L-Cu2+ complex could be used as a fluorescent probe to detect hypochlorite, with the advantages of rapid, selective, wide linear range and low detection limit.

Colorimetric sensing of iodide ions based on unmodified gold nanoparticles and the distinctive antiaggregation-to-aggregation process.

A highly sensitive and selective colorimetric analysis method based on unmodified gold nanoparticles (AuNPs) to detect iodide ions (I- ) in solution in the presence of hexadecyl trimethyl ammonium bromide (CTAB) and mercury ions (Hg2+ ) has been successfully developed. Hg2+ could form a gold amalgam with AuNPs to protect AuNPs from CTAB-induced aggregation caused by the electrostatic attraction between CTAB and citrate ion-covered AuNPs. When a mixture of Hg2+ and I- was added to the solution of AuNPs, the formation of the HgI2 complex destroyed the protection of Hg2+ for AuNPs, which led to the aggregation of AuNPs accompanied with the change in colour of the solution from red to grey black and decrease in the absorbance of AuNPs at 520 nm. There was a good linear relationship between A520nm and I- concentration from 0 to 800 nM with a low limit of detection (LOD) of 4.2 nM. Furthermore, this simple and reliable colorimetric sensor has been applied successfully to the detection of I- in practical samples.

Colorimetric Sensor for Thiocyanate Based on Anti-aggregation of Gold Nanoparticles in the Presence of 2-Aminopyridine.

Based on the anti-aggregation mechanism of citrate stabilized gold nanoparticle (AuNPs), a new specific and sensitive colorimetric sensor for thiocyanate (SCN-) was developed. In this scheme, the AuNPs were aggregated in the presence of the aggregating agent 2-aminopyridine (2-AP) due to electrostatic attraction. The solution color changed from red to blue. When SCN- was present, SCN- formed a sulfur-gold bond with the AuNPs to protect the AuNPs from aggregation. Thiocyanate can be detected by the color change of the solution from blue to red. The results showed that the absorbance ratio A675/A520 was linear with the concentration of SCN- in the range of 0.4 - 1.2 µmol L-1 by UV-Vis spectroscopy. The limit of detection (LOD) of this assay was 0.37 µmol L-1. The system also had excellent selectivity and anti-interference ability. In addition, this method was successfully used for the detection of SCN- in actual water samples and achieved good results.

Core-shell Au@Pt Nanoparticles Catalyzed Luminol Chemiluminescence for Sensitive Detection of Thiocyanate.

In this study, core-shell Au@Pt nanoparticles (Au@Pt NPs) with peroxidase catalytic activity were synthesized by the seed-mediated method, and were used to catalyze the reaction of luminol-H2O2 to enhance the chemiluminescence (CL) intensity. It was found that thiocyanate (SCN-) can effectively inhibit the catalytic activity of Au@Pt NPs. Based on this phenomenon, a method to detect SCN- by using the Au@Pt NPs-catalytic luminol-H2O2 CL system was established, which has an ultra-low detection limit and an ultra-wide linear range, as well as the advantages of being simple and having low-cost and convenient operation. The research mechanism indicated that SCN- could be adsorbed on the surface of Au@Pt NPs and occupies the active sites of Pt nanostructures, which led to a decrease in the amount of Pt0 and a loss of the excellent catalytic activity of Au@Pt NPs. After optimizing the experimental conditions, this assay for detecting SCN- exhibited a good linear range from 5 to 180 nM, and the low detection limit was 2.9 nM. In addition, this approach has been successfully applied to the detection of SCN- in tap-water samples, which has practical application value and embodies good development prospects.