Shenling Baizhu San ameliorates non-alcoholic fatty liver disease in mice by modulating gut microbiota and metabolites.

Purpose: The prevalence of non-alcoholic fatty liver disease (NAFLD) and its related mortality is increasing at an unprecedented rate. Traditional Chinese medicine (TCM) has been shown to offer potential for early prevention and treatment of NAFLD. The new mechanism of "Shenling Baizhu San" (SLBZS) is examined in this study for the prevention and treatment of NAFLD at the preclinical level. Methods: Male C57BL/6J mice were randomly divided into three groups: normal diet (ND), western diet + CCl4 injection (WDC), and SLBZS intervention (WDC + SLBZS). Body weights, energy intake, liver enzymes, pro-inflammatory factors, and steatosis were recorded in detail. Meanwhile, TPH1, 5-HT, HTR2A, and HTR2B were tested using qRT-PCR or ELISA. Dynamic changes in the gut microbiota and metabolites were further detected through the 16S rRNA gene and untargeted metabolomics. Results: SLBZS intervention for 6 weeks could reduce the serum and liver lipid profiles, glucose, and pro-inflammatory factors while improving insulin resistance and liver function indexes in the mice, thus alleviating NAFLD in mice. More importantly, significant changes were found in the intestinal TPH-1, 5-HT, liver 5-HT, and related receptors HTR2A and HTR2B. The 16S rRNA gene analysis suggested that SLBZS was able to modulate the disturbance of gut microbiota, remarkably increasing the relative abundance of probiotics (Bifidobacterium and Parvibacter) and inhibiting the growth of pro-inflammatory bacteria (Erysipelatoclostridium and Lachnoclostridium) in mice with NAFLD. Combined with metabolomics in positive- and negative-ion-mode analyses, approximately 50 common differential metabolites were selected via non-targeted metabolomics detection, which indicated that the targeting effect of SLBZS included lipid metabolites, bile acids (BAs), amino acids (AAs), and tryptophan metabolites. In particular, the lipid metabolites 15-OxEDE, vitamin D3, desoxycortone, and oleoyl ethanol amide were restored by SLBZS. Conclusion: Integrating the above results of multiple omics suggests that SLBZS ameliorates NAFLD via specific gut microbiota, gut-derived 5-HT, and related metabolites to decrease fat accumulation in the liver and inflammatory responses.

Extracting Technicians' Skills for Human-Machine Collaboration in Aircraft Assembly.

Research on the efficiency and quality issues faced in aircraft assembly was conducted in this article. A new method of human-machine collaborative riveting was proposed, which combined the flexibility of manual collaboration with the precise control of automatic riveting. The research works include: (1) a theoretical model of pneumatic hammer riveting was established to clarify the principle and parameters of riveting process. (2) A smart bucking bar was designed to support the data collection and extraction of manual collaborative riveting process. (3) An automatic riveting experimental platform was designed to test the automatic riveting process incorporating the extracted manual riveting process parameters, and further an optimization strategy was proposed for the automatic riveting process. (4) A human-machine collaborative riveting experimental platform was developed to conduct the verification work. Through the theoretical analysis, experimental research, system scheme design, and process parameters optimization, the application and verification of human-machine collaborative assembly technology have been achieved. This technology is expected to be comprehensively promoted in the field of aircraft manufacturing, and for breaking through the current difficulties of low production efficiency and poor assembly quality control.

IL-8 Produced Via Bidirectional Communication Between Prostate Cancer and M2 Macrophages as a Potential Diagnostic and Prognostic Biomarker.

PURPOSE: Owing to the mortality associated with metastatic prostate cancer and the shortcomings of the current parameters in predicting the disease prognosis, we require the identification of viable biomarkers, which would help in the diagnosis and prognosis of the disease. We aimed to determine whether the interleukin-8 level in the tumor microenvironment could serve as a potential clinical diagnostic marker and prognostic factor for prostate cancer. METHODS: The migration assay of prostate cancer cells was performed in an in vitro co-culture model. Cell lines PC3 and DU145 were divided into two groups and co-cultured with M0 and M2 macrophages, respectively. We used reverse transcription-quantitative polymerase chain reaction to detect M2 macrophage marker expression levels. Immunohistochemistry analyses of tissue microarrays were performed to analyze the correlation between the increased expression of interleukin-8 and the prognosis of prostate cancer. A retrospective analysis based on 142 residual serum specimens was performed to analyze the level of interleukin-8. RESULTS: We observed that M2 macrophages promoted the migration of prostate cancer cells and significantly increased the concentrations of interleukin-8 in the co-culture supernatants. We observed increased expression of CD163 and interleukin-8 in prostate cancer tissues. Furthermore, the levels of interleukin-8 in the serum of prostate cancer patients were higher than those in healthy controls. Untreated patients had higher levels of interleukin-8, which could be a predictor of a higher metastasis rate. CONCLUSION: These results suggest that interleukin-8 produced via bidirectional communication between prostate cancer cells and M2 macrophages is a putative biomarker for prostate cancer diagnosis and treatment.

High-cholesterol diet promotes depression- and anxiety-like behaviors in mice by impact gut microbe and neuroinflammation.

Neuropsychiatric disorders, including anxiety and depression, are one of the most common mental illnesses worldwide. A growing body of evidence shows that there is a complex relationship between dietary patterns and mental health. In our study, C57BL/6J mice were divided into three groups: control diet group (CON, 10 % kcal fat), high-cholesterol diet model group (HCD, 42.0 % kcal fat + 1.25 % kcal Cholesterol), and chronic restraint stress group (CRS, 10 % kcal fat) which as a positive control group for the depression model. Six weeks later, depressive- and anxiety-like behavior were evaluated for using the OFT, SPT and TST. Glucose intolerance and liver fat were detected by IGTT and liver lipid kit. The expression of peripheral and central inflammation was detected by LEGEND plex kits. 5-HT (also named 5-hydroxytryptamine, 5-HT) and related receptors expression were monitored by ELISA, RT-PCR and Western blot. Meantime, gut microbe of stool samples was performed by 16S rRNA gene sequencing. Similar to CRS model, short-term HCD intervention induced anxiety and depression-like behavior behavioral abnormalities in mice. HCD consumption resulted in significantly increased body weight, liver fat (LDL-C, TC, TG), peripheral inflammation (IL-1ß, MCP-1, IL-17A) and neuroinflammation (MCP-1). The concentration of 5-HT increased in the hippocampus, meanwhile, the expression of 5-HT receptor HTR2A was distinct in different regions of the brain tissue. More importantly, we found that compared with the CON diet, HCD induced the decrease of intestinal flora diversity, especially the decrease the relative abundance of Akkermansia_muciniphila, which was statistically significant. Further, Pearson correlation analysis showed that Akkermansia_muciniphila was significantly negatively correlated with the concentration of MCP-1, IL-17A in serum and 5-HT in hippocampus. Therefore, we speculated that the disorder of neuroinflammation induced by HCD consumption promotes depression- and anxiety-like behaviors in mice through the gut microbe.

RFID-based sensing in smart packaging for food applications: A review.

The global pandemic COVID-19 has led to an increase in the number of people purchasing food online, which has brought to a higher demand on the food supply chain. Such as the need to collect more information related to food safety and quality in real-time. Strengthening management of food logistics information flow can reduce food loss and waste and bring better quality and safety of food to consumers. In this review, the importance and applicability of RFID (Radio Frequency Identification) technology to smart food packaging are described. This study emphasizes the recent advancement of the RFID tags in humidity, temperature, gas, pH, integrity, and traceability sensor applications in connection with food packaging. RFID sensors are more suitable for smart packaging both in terms of sensing ability and data transmission. A simpler, low-cost, more robust and less power-demanding sensors network is the development direction of smart packaging in the future. Chipless RFID sensors have the potential to achieve these functions. But it still faces many challenges to be overcome. For example, biocompatible, cost, reading range, multi-tag collision, multi-parameter sensors, recycling issues, security and privacy of RFID system should be solved.

Effect of PCI Standardized Telephone Follow-Up Service Mode on Out-of-Hospital Complications, Rehospitalization Rate, and Quality of Life of Discharged Patients with Acute Coronary Syndrome after PCI.

Objective: To explore the effect of percutaneous coronary intervention (PCI) standardized telephone follow-up service mode on out-of-hospital complications, rehospitalization rate, and life quality of discharged acute coronary syndrome (ACS) patients after PCI. Methods: From August 2020 to March 2022, 218 ACS patients who were discharged after PCI were included. The controls accepted routine nursing care, and the researches accepted PCI standardized telephone follow-up service mode. The nursing satisfaction, rehospitalization rate, out-of-hospital complication rate, blood lipid level, and life quality score were taken as the comparisons. Results: The nursing satisfaction of study group (100.00%) was significantly higher than that of control group (88.07%). The rehospitalization rate was dramatically lower in the study group (3/109; 2.75%) than in the control group (25/109; 22.94%) (P < 0.05). In addition, compared with the control group, the incidence of complications (acute myocardial infarction and angina pectoris) was significantly reduced in the study group outside the hospital (P < 0.05). The blood lipid levels of TCHO, TG, LDL-C, and HDL-C were lower in the study group than in the controls. Further, after nursing, the quality of life score of the two groups was both decreased with a higher quality of life score in the study group (P < 0.05). Conclusion: The application of PCI standardized telephone follow-up service mode in discharged patients with acute coronary syndrome after PCI can reduce out-of-hospital complications and rehospitalization rate and improve blood lipid level and life quality.

Evaluating the diagnostic value of using metagenomic next-generation sequencing on bronchoalveolar lavage fluid and tissue in infectious pathogens located in the peripheral lung field.

BACKGROUND: Metagenomic next-generation sequencing (mNGS) exerts a vital part in accurately diagnosing pulmonary infection. However, the diagnostic value of different samples obtained by virtual bronchoscopic navigation (VBN) combined with mNGS for pathogen detection in infections located in the peripheral lung field (PLF) is still unclear. METHODS: Patients infected from July 2018 to February of the following year were carefully analyzed and divided into two parts, namely, non-infectious disease group and the infectious disease group. Then bronchial expansion tests were performed for each subject, collected liquid specimens and tissue standards, and conducted regular mNGS and microbiological detection and analysis. The value of mNGS and culture in pathogen detection was compared, at the same time, the performance of tissue mNGS and bronchoalveolar lavage fluid (BALF) mNGS in the diagnosis process was compared. When discrete variables were processed, Pearson χ2 and Fisher's exact test could be used to perform categorical variables analysis. Continuous variables were analyzed and compared by Mann-Whitney U test. RESULTS: After mNGS diagnosis, Acinetobacter baumannii, Pseudomonas aeruginosa and Rothia mucilaginosa were the bacterial species showing the highest abundances. In addition, mNGS achieved the sensitivities in the detection of pathogens in tissues and BALF of 72.9% and 81.4%, respectively, and it is higher than conventional culture. Bacterial diagnostic sensitivity was significantly different between BALF and tissue using mNGS (95.0% vs. 62.5%, P=0.03). The sensitivity and specificity of BALF in detecting fungal infections were not significantly different from those of mNGS. A consistency test showed that these two methods had some degree of consistency (k=0.673, P=0.000). CONCLUSIONS: This study showed that the mNGS in BALF samples and the mNGS in tissue samples which could be used to test for pathogens in the lungs. The sensitivity will increase when mNGS is combined with culture. Also, mNGS of BALF and tissues had some degree of consistency to detect fungal infections, whereas mNGS of BALF had better sensitivity to detect bacterial infection than mNGS of tissues.

Visible light-promoted intermolecular cyclization/aromatization of chalcones and 2-mercaptobenzimidazoles via an EDA complex and a mechanism study.

Visible-light-promoted cyclization and aromatization of chalcones with 2-mercaptobenzimidazoles have been successfully developed to obtain diverse imidazo[2,1-b]thiazoles, and C-S and C-N bonds were constructed in one step. The reaction uses oxygen in the air as an oxidant, and the method does not need an external photocatalyst or a transition metal catalyst. The strategy features mild conditions, a simple system, readily accessible feedstocks, and a friendly environment. UV absorption spectroscopy and control experiments have shown that the reaction mechanism involves the formation of an electron-donor-acceptor (EDA) complex from thiolate anions and chalcones. In order to verify the mechanism, we studied the structure and HOMO/LUMO of the EDA complex by density functional theory (DFT) calculations. The results show that the π-π stacking between chalcones and 2-mercaptobenzimidazoles will cause a red shift of the UV absorption wavelength in the presence of Cs2CO3, and also provide a theoretical basis for the electron transfer of EDA complexes.

Critical Review of Synthesis, Toxicology and Detection of Acyclovir.

Acyclovir (ACV) is an effective and selective antiviral drug, and the study of its toxicology and the use of appropriate detection techniques to control its toxicity at safe levels are extremely important for medicine efforts and human health. This review discusses the mechanism driving ACV's ability to inhibit viral coding, starting from its development and pharmacology. A comprehensive summary of the existing preparation methods and synthetic materials, such as 5-aminoimidazole-4-carboxamide, guanine and its derivatives, and other purine derivatives, is presented to elucidate the preparation of ACV in detail. In addition, it presents valuable analytical procedures for the toxicological studies of ACV, which are essential for human use and dosing. Analytical methods, including spectrophotometry, high performance liquid chromatography (HPLC), liquid chromatography/tandem mass spectrometry (LC-MS/MS), electrochemical sensors, molecularly imprinted polymers (MIPs), and flow injection-chemiluminescence (FI-CL) are also highlighted. A brief description of the characteristics of each of these methods is also presented. Finally, insight is provided for the development of ACV to drive further innovation of ACV in pharmaceutical applications. This review provides a comprehensive summary of the past life and future challenges of ACV.

[Influencing factors of weaning outcome of intensive care unit patients with planned extubation].

OBJECTIVE: To determine the risk factors of extubation failure and its effect on the prognosis of patients who had successfully passed a spontaneous breathing trial (SBT). METHODS: The clinical data of patients with mechanical ventilation more than 24 hours who passed SBT admitted to department of intensive care unit (ICU) of First Hospital of Qinhuangdao from November 2018 to November 2019 were retrospectively analyzed. According to the outcome of weaning within 48 hours after weaning, patients were divided into weaning success group and weaning failure group. The baseline data, the presence of basic cardiopulmonary diseases, B-type natriuretic peptide (BNP), fluid balance, albumin and hemoglobin within 24 hours before weaning, the time of mechanical ventilation before weaning, rapid shallow breathing index (RSBI) during SBT, oxygenation index, cough peak flow at the end of SBT, and prognostic indicators were collected. The outcome of weaning was taken as the dependent variable, and the observation factors were taken as the independent variable for univariate analysis. The factors with statistical significance in univariate analysis were analyzed by binary Logistic regression to determine the influencing factors of weaning failure. RESULTS: Of the 204 patients, 167 (81.9%) were successfully weaned, and 37 (18.1%) failed. Compared with the weaning success group, the total duration of mechanical ventilation and the length of ICU stay in the weaning failure group were significantly longer [days: 13.0 (7.5, 23.5) vs. 5.0 (3.0, 8.0), 17.0 (12.5, 31.0) vs. 10.0 (6.0, 15.0), both P < 0.01], and the tracheotomy rate and mortality were significantly higher (32.4% vs. 0%, 51.4% vs. 0%, both P < 0.01). Univariate analysis showed that there were significant differences in age, proportion of patients with cardiopulmonary diseases, BNP and cough peak flow between weaning failure group and weaning success group [age (years old): 70.65±15.78 vs. 62.69±15.82, cardiopulmonary diseases: 62.2% vs. 24.6%, BNP (ng/L): 416.87 (32.70, 1 225.80) vs. 45.36 (10.00, 273.60), cough peak flow (L/min): 59.89±9.06 vs. 83.84±16.52, all P < 0.01]. However, there were no significant differences in gender, acute physiology and chronic health evaluation II (APACHE II) at admission, mechanical ventilation time before weaning, albumin, hemoglobin, oxygenation index, RSBI and fluid balance 24 hours before weaning between weaning failure group and weaning success group [male: 51.4% vs. 68.3%, APACHE II: 16.70±6.65 vs. 15.67±6.28, mechanical ventilation time before weaning (days): 6.0 (2.5, 11.0) vs. 5.0 (3.0, 8.0), albumin (g/L): 27.78±4.15 vs. 27.76±4.46, hemoglobin (g/L): 102.43±15.80 vs. 100.61±17.19, oxygenation index (mmHg, 1 mmHg = 0.133 kPa): 359.33±79.83 vs. 365.75±78.23, RSBI (times×L-1×min-1): 50.73±24.97 vs. 46.76±15.53, positive fluid balance: 70.3% vs. 69.5%, all P > 0.05]. The results of binary Logistic regression analysis showed that age ≥ 75 years old [odds ratio (OR) = 3.099, 95% confidence interval (95%CI) was 1.003-9.574, P = 0.049], presence of cardiopulmonary diseases (OR = 3.599, 95%CI was 1.126-11.498, P = 0.031), BNP within 24 hours before weaning (OR = 1.002, 95%CI was 1.000-1.003, P = 0.005) were the risk factors of extubation failure, while cough peak flow at the end of SBT was the protective factor (OR = 0.869, 95%CI was 0.823-0.917, P = 0.000). CONCLUSIONS: For patients who had successfully passed SBT, age ≥ 75 years old, the presence of cardiopulmonary diseases and an increased level of BNP within 24 hours were the risk factors of extubation failure. In addition, the higher the cough peak flow at the end of SBT, the lower the risk of weaning failure will be.

[Tolerogenic dendritic cells alleviate joint inflammation and arthropathy via reducing Th1 and Th17 cell proportion in CIA rats].

Objective To investigate the effects of tolerogenic dendritic cells (tolDCs) induced by nuclear factor κB oligodeoxynucleotide decoy (NF-κB ODN decoy) on Th1 cells, Th2 cells, Th17 cells and regulatory T cells (Tregs) and the intervention effects on collagen-induced arthritis (CIA) rats. Methods SD female rats used to establish CIA rat models were divided into four groups, including a CIA model group, a bovine type II collagen-decoy-dendritic cell (Col2-decoy DC) treatment group, a blank control group, and a Col2-decoy DC control group. On the 20th days after the first immunization, the rats were injected with tolDCs via the tail vein, and the rats were sacrificed on the 7th weeks. The proportions of Th1 cells, Th2 cells, Th17 cells, and Tregs in the rat spleen were detected by flow cytometry. The ankle joint pathomorphological change was evaluated by HE staining, and the arthritis index (AI) was scored. Results Compared with the CIA model group, the Col2-decoy DC group had lower AI and milder ankle joint pathomorphological change. The percentages of Th1 cells and Th17 cells in the spleen CD4+ T cells decreased, while the percentages of Th2 cells and Tregs increased. Conclusion The treatment of tolDCs can alleviate the inflammation and arthropathy of CIA rats by reducing the proportion of Th1 and Th17 cells in CD4+ T cells.

Dietary and metabolic risk of neuropsychiatric disorders: insights from animal models.

Neuropsychiatric disorders are major causes of the global burden of diseases, frequently co-occurring with multiple co-morbidities, especially obesity, type 2 diabetes mellitus, non-alcoholic fatty liver disease and its various risk factors in the metabolic syndrome. While the determining factors of neuropsychiatric disorders are complex, recent studies have shown that there is a strong link between diet, metabolic state and neuropsychiatric disorders, including anxiety and depression. There is no doubt that rodent models are of great value for preclinical research. Therefore, this article focuses on a rodent model of chronic consumption of high-fat diet (HFD), and/or the addition of a certain amount of cholesterol or sugar, meanwhile, summarising the pattern of diet that induces anxiety/depressive-like behaviour and the underlying mechanism. We highlight how dietary and metabolic risk influence neuropsychiatric behaviour in animals. Changes in dietary patterns, especially HFD, can induce anxiety- or depression-like behaviours, which may vary by diet exposure period, sex, age, species and genetic background of the animals used. Furthermore, dietary patterns significantly aggravate anxiety/depression-like behaviour in animal models of neuropsychiatric disorders. The mechanisms by which diet induces anxiety/depressive-like behaviour may involve neuroinflammation, neurotransmitters/neuromodulators, neurotrophins and the gut-brain axis. Future research should be focused on elucidating the mechanism and identifying the contribution of diet and diet-induced metabolic risk to neuropsychiatric disorders, which can form the basis for future clinical dietary intervention strategies for neuropsychiatric disorders.

Reduction of miR-744 delivered by NSCLC cell-derived extracellular vesicles upregulates SUV39H1 to promote NSCLC progression via activation of the Smad9/BMP9 axis.

BACKGROUND: Non-small cell lung cancer (NSCLC) is a common type of lung cancer. Extracellular vehicles (EVs) are nano-sized particles containing proteins, lipids, and miRNAs secreted by various cells, which play important roles in the development of lung cancer by regulating a wide range of signaling pathways. This study focused on elucidating a potential mechanism by which EVs promote the development of NSCLC. METHODS: Expression levels of miR-744, SUV39H1, Smad9, and BMP4 in clinical tissue samples of NSCLC patients and cell lines were quantified by RT-qPCR and/or western blot analysis. The interaction between SUV39H1 and miR-744 was identified by dual-luciferase reporter assay. miR-744, SUV39H1, and BMP4 expression levels were modulated in A549 and H460 cells, in order to evaluate their effects on cell proliferation, colony formation and cell cycle. A NSCLC xenograft mouse model was used to verify the in vitro findings. NSCLC cell-derived EVs and normal bronchial epithelial cell-derived EVs were isolated and their roles in NSCLC development were evaluated in vivo and in vitro. RESULTS: miR-744 expression was lower in cancer cell-derived derived EVs than in normal lung epithelial cell-derived EVs. Reduced miR-744 expression in EVs upregulated SUV39H1 in NSCLC cells and further increased BMP4 levels to promote NSCLC development. BMP4 was upregulated in NSCLC cells upon suppression of Smad9 mediated by SUV39H1. Reduced miR-744 expression transferred from cancer cell-derived EVs into NSCLC cells enhanced cancer development. CONCLUSION: Overall, our findings unveiled a mechanism whereby miR-744 delivered by NSCLC-derived EVs upregulated SUV39H1, activating the Smad9/BMP9 axis and thus promoted cancer development.

Chitin nanocrystals assisted 3D printing of polycitrate thermoset bioelastomers.

Citrate-based thermoset bioelastomer has numerous tissue engineering applications. However, its insoluble and unmeltable features restricted processing techniques for fabricating complex scaffolds. Herein, direct ink writing (DIW) was explored for 3D printing of poly(1, 8-octanediol-co-Pluronic F127 citrate) (POFC) bioelastomer scaffolds considering that POFC prepolymer (pre-POFC) was waterborne and could form a stable emulsion. The pre-POFC emulsion couldn't be printed, however, chitin nanocrystal (ChiNC) could be as a rheological modifier to tune the flow behavior of pre-POFC emulsion, and thus DIW printing of POFC scaffolds was successfully realized; moreover, ChiNC was also as a supporting agent to prevent collapse of filaments during thermocuring, and simultaneously as a biobased nanofiller to reinforce scaffolds. The rheological analyses showed the pre-POFC/ChiNC inks fulfilled the requirements for DIW printing. The printed scaffolds exhibited low swelling, and good performances in strength and resilence. Furthermore, the entire process was easily performed and eco-friendly.

DiR-labeled tolerogenic dendritic cells for targeted imaging in collagen- induced arthritis rats.

Tolerogenic dendritic cells (tolDCs) are immunosuppressive cells and play an important role in rheumatoid arthritis (RA) as immunotherapeutic tools. We aimed to investigate whether allogeneic tolDCs (allo-tolDCs) and autologous tolDCs (auto-tolDCs) had long-time tolerogenic potential in vivo and improve arthritis in collagen-induced arthritis (CIA) rats. TolDCs were induced by NF-κB Decoy ODN, and loaded with Bovine Type II collagen (CII- loaded tolDCs) and identified by flow cytometry, and labeled with DiR and injected into CIA rats. The biodistribution of DiR-labeled tolDCs was monitored by IVIS imaging at different time points. Major organs were harvested and analyzed by ex-in vivo cell imaging. The tolDCs were successfully constructed, along with expressing low levels of CD80 and CD86 compared to DCs. The fluorescent signals of all DiR (+) groups were observed at least 25 days, and as long as 35 days. DiR (+) CII- loaded allo-and auto-tolDCs at post injection mainly distributed in the chest and abdomen and gradually moved to limb joints over time. The allo- and auto-tolDCs decreased the expression of IFN-γ and IL-2 in CIA rats with different severity compared to CIA rats without tolDCs treatment, while significantly increased the expression of IL-4 and IL-10. Additionally, these tolDCs ameliorated the ankle joints injury in CIA rats with different severity. The both allo- and auto-tolDCs showed long-time tolerogenic potential in vivo and ameliorated arthritis in CIA rats with different severity.

Design, Bioanalytical, and Biomedical Applications of Aptamer-Based Hydrogels.

Aptamers are special types of single-stranded DNA generated by a process called systematic evolution of ligands by exponential enrichment (SELEX). Due to significant advances in the chemical synthesis and biotechnological production, aptamers have gained considerable attention as versatile building blocks for the next generation of soft materials. Hydrogels are high water-retainable materials with a three-dimensional (3D) polymeric network. Aptamers, as a vital element, have greatly expanded the applications of hydrogels. Due to their biocompatibility, selective binding, and molecular recognition, aptamer-based hydrogels can be utilized for bioanalytical and biomedical applications. In this review, we focus on the latest strategies of aptamer-based hydrogels in bioanalytical and biomedical applications. We begin this review with an overview of the underlying design principles for the construction of aptamer-based hydrogels. Next, we will discuss some bioanalytical and biomedical applications of aptamer-based hydrogel including biosensing, target capture and release, logic devices, gene and cancer therapy. Finally, the recent progress of aptamer-based hydrogels is discussed, along with challenges and future perspectives.

Simultaneous and sensitive determination of ascorbic acid, dopamine and uric acid via an electrochemical sensor based on PVP-graphene composite.

A method with high sensitivity, good accuracy and fast response is of ever increasing importance for the simultaneous detection of AA, DA and UA. In this paper, a simple and sensitive electrochemical sensor, which based on the polyvinylpyrrolidone (PVP)-graphene composite film modified glassy carbon electrode (PVP-GR/GCE), was presented for detecting ascorbic acid (AA), dopamine (DA) and uric acid (UA) simultaneously. The PVP-GR/GCE has excellent electrocatalytic activity for the oxidation of AA, DA and UA. The second-order derivative linear sweep voltammetry was used for the electrochemical measurements. The peak potential differences of DA-AA, DA-UA, and UA-AA (measured on the PVP-GR/GCE) were 212, 130 and 342 mV respectively. Besides, the over potential of AA, DA and UA reduced obviously, so did the peak current increase. Under the optimum conditions, the linear ranges of AA, DA and UA were 4.0 µM-1.0 mM, 0.02-100 µM, and 0.04-100 µM, respectively. The detection limits were 0.8 µM, 0.002 µM and 0.02 µM for AA, DA, and UA. The electrochemical sensor presented the advantages of high sensitivity and selectivity, excellent reproducibility and long-term stability. Furthermore, the sensor was successfully applied to the analysis of real samples.

Electrochemical Sensing Fabricated with Ta2O5 Nanoparticle-Electrochemically Reduced Graphene Oxide Nanocomposite for the Detection of Oxytetracycline.

A novel tantalum pentoxide nanoparticle-electrochemically reduced graphene oxide nanocomposite-modified glassy carbon electrode (Ta2O5-ErGO/GCE) was developed for the detection of oxytetracycline in milk. The composition, structure and morphology of GO, Ta2O5, and Ta2O5-ErGO were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Oxytetracycline electrochemical behavior on the bare GCE, GO/GCE, ErGO/GCE, and Ta2O5-ErGO/GCE was studied by cyclic voltammetry. The voltammetric conditions (including scan rate, pH, deposition potential, and deposition time) were systematically optimized. With the spacious electrochemical active area, the Ta2O5-ErGO/GCE showed a great magnification of the oxidation signal of oxytetracycline, while that of the other electrodes (GCE, GO/GCE, ErGO/GCE) could not reach the same level. Under the optimum conditions, the currents were proportional to the oxytetracycline concentration in the range from 0.2 to 10 µM, and a low detection limit of 0.095 µM (S/N = 3) was detectable. Moreover, the proposed Ta2O5-ErGO/GCE performed practically with satisfactory results. The preparation of Ta2O5-ErGO/GCE in the current work provides a minor outlook of detecting trace oxytetracycline in milk.

Sensitive Voltammetric Sensor for Tryptophan Detection by Using Polyvinylpyrrolidone Functionalized Graphene/GCE.

In this paper, an electrochemical method for the measurement of tryptophan (Trp) was developed based on a glassy carbon electrode modified with polyvinylpyrrolidonefunctionalized graphene (PVP-GR)/glassy carbon electrode (GCE). In 0.1 M phosphate buffer solution (PBS, pH = 2.2), compared with bare GCE, PVP/GCE, and GR/GCE, the oxidation peak current of Trp increased dramatically at PVP-GR/GCE. The oxidation mechanism of Trp on the PVP-GR/GCE was discussed and the experimental conditions were optimized. Under the best experimental conditions, the oxidation peak current of Trp was proportional to its concentration in the range of 0.06 µM-10.0 µM and 10.0-100.0 µM, and the limit of detection (LOD) was 0.01 µM (S/N = 3). The target modified electrode with excellent repeatability, stability and selectivity, was successfully applied to detectTrp in drugs and biological samples.