In-situ growth of nitrogen-doped carbonized polymer dots on black phosphorus for electrochemical DNA biosensor of Escherichia coli O157: H7.

Sensitive and accurate detection technology for pathogenic bacteria is of great social and economic significance in foodborne disease and food safety. In this paper, a novel portable electrochemical DNA biosensor for the detection of specific DNA sequence of Escherichia coli (E. coli) O157: H7 was constructed. To enhance the performance of the electrochemical sensor, a functionalized nitrogen-doped carbonized polymer dots in-situ grown on few-layer black phosphorus (N-CPDs@FLBP) was synthesized and used as the modifier on the surface of screen-printed electrode. Combining gold nanoparticles as immobilization matrix and methylene blue as electrochemical indicator, the analytical performance of this electrochemical DNA biosensor was evaluated using standard complementary ssDNA sequence in the linear concentration range from 1.0 × 10-19 to 1.0 × 10-6 mol/L with a low detection limit as 3.33 × 10-20 mol/L (3 σ). Furthermore, the portable electrochemical DNA biosensor was proposed based on polymerase chain reaction amplification for the detection of the E. coli O157: H7 genomic DNA from chicken meat, which verified the feasibility for practical samples detection. The research has great theoretical and practical significance for the development of electrochemical biosensor of pathogenic bacteria.

COVID-19 pandemic: study on simple, easy, and practical relaxation techniques while wearing medical protective equipment.

BACKGROUND: No studies have reported on how to relieve distress or relax in medical health workers while wearing medical protective equipment in coronavirus disease 2019 (COVID-19) pandemic. The study aimed to establish which relaxation technique, among six, is the most feasible in first-line medical health workers wearing medical protective equipment. METHODS: This was a two-step study collecting data with online surveys. Step 1: 15 first-line medical health workers were trained to use six different relaxation techniques and reported the two most feasible techniques while wearing medical protective equipment. Step 2: the most two feasible relaxation techniques revealed by step 1 were quantitatively tested in a sample of 65 medical health workers in terms of efficacy, no space limitation, no time limitation, no body position requirement, no environment limitation to be done, easiness to learn, simplicity, convenience, practicality, and acceptance. RESULTS: Kegel exercise and autogenic relaxation were the most feasible techniques according to step 1. In step 2, Kegel exercise outperformed autogenic relaxation on all the 10 dimensions among the 65 participants while wearing medical protective equipment (efficacy: 24 v. 15, no space limitation: 30 v. 4, no time limitation: 31 v. 4, no body position requirement: 26 v. 4, no environment limitation: 30 v. 11, easiness to learn: 28 v. 5, simplicity: 29 v. 7, convenience: 29 v. 4, practicality: 30 v. 14, acceptance: 32 v. 6). CONCLUSION: Kegel exercise seems a promising self-relaxation technique for first-line medical health workers while wearing medical protective equipment among COVID-19 pandemic.

ZnO-reduced graphene oxide composite based photoelectrochemical aptasensor for sensitive Cd(II) detection with methylene blue as sensitizer.

In this paper a photoelectrochemical (PEC) aptasensor based on specific recognition with conformational changed after the target Cd(II) identification was fabricated. A ZnO and reduced graphene oxide (ZnO-rGO) nanocomposite with enhanced PEC activity was designed as photoactive material. After the further incorporation of gold nanoparticles (AuNPs) with ZnO-rGO nanocomposite, the enhanced photocurrent signal could be detected owing to the localized surface plasmon resonance and good conductivity of AuNPs. In addition, AuNPs were used as anchors for immobilization of -SH modified aptamer S1. After that aptamer S2 was paired with S1 sequence to form complementary double stranded DNA (dsDNA) on the electrode surface. Methylene blue (MB) was acted as sensitizer and assembled in dsDNA structure to amplify photocurrent response. When Cd(II) was bound to the aptamer presented on the sensing interface, S2 specifically recognized and captured Cd(II), which resulted in the unwinding of dsDNA structure and the separation of MB molecules from the electrode surface with photocurrent response decreased. The photocurrent was detected by a double-working-electrode system, which used the modified electrode as the first working electrode and glassy carbon electrode (GCE) as the second working electrode. Dopamine (DA) was added to the electrolyte and acted as the electron donor, which could be oxidized on the modified electrode and reduced on the GCE to form a cyclic reaction, leading to the enhanced photocurrent response with improved photocurrent stability. This MB sensitized PEC aptasensor exhibited a high sensitivity with a detection limit of 1.8 × 10-12 mol/L (3σ). Thus, a highly sensitive aptasensor with double-working-electrode detection method for Cd(II) determination were established and further applied to the water samples analysis.

Development of an on-line analytical platform to screen haptens in shuxuening injection based on high-performance liquid chromatography coupled with ion-trap multistage mass spectrometry and human serum albumin fluorescence detection.

Shuxuening injection (SXNI), one of the traditional Chinese medicine injections (TCMI), is widely used for the treatment of cardiovascular diseases in the clinic. However, its allergic reactions have impeded the clinical applications of SXNI, such adverse reactions have not been well understood due to the lack of methods for detecting haptens. In this study, a high-performance liquid chromatography-diode-array detector-multi-stage mass spectrometry-human serum albumin-fluorescence detector (HPLC-DAD-MSn-HSA-FLD) system was established to identify and screen haptens for the first time. Flavones, flavonols and their glycosides in SXNI showed strong HSA binding ability in different degrees. Fifteen of these compounds were used to study the association of HSA binding ability and sensitizability using isothermal titration calorimetry (ITC) and fluorescence techniques, furthermore, RBL-2H3 cell experiments were conducted to verify the results. It was found that ginkgolides showed no sensitizability, while flavones and flavonol aglycones showed stronger sensitizability than their glycosides. The system was proven to be precise, stable and reproducible, which lays a foundation for screening haptens in SXNI and relevant samples.

Wuzi Yanzong pill, a Chinese polyherbal formula, alleviates testicular damage in mice induced by ionizing radiation.

BACKGROUND: Chinese medicine Wuzi Yanzong pill (WZYZP) was firstly documented in ancient Chinese medical works "She Sheng Zhong Miao Fang" by Shi-Che Zhang in 1550 AD. The traditional herbal formula is widely used in treating nephrasthenia lumbago, prospermia, erectile dysfunction and male sterility. The present study was to explore the effects of WZYZP on ionizing irradiation-induced testicular damage in mice. METHODS: The pelvic region of male mice was exposed to X-rays for inducing testicular damage. The effects of WZYZP on testicular damage were evaluated in terms of testes weight, sperm quantity and motility, testes oxidative status and serum hormone levels. The alterations in testicular structure were examined by hematoxylin-eosin staining. Additionally, changes in proliferating cell nuclear antigen (PCNA) expression of testes were explored by western blot. RESULTS: Pelvic exposure to x-ray induced reduction in testes weight and sperm quality, along with oxidative stress and abnormal testicular architecture in testes. Oral administration of WZYZP for 3 weeks markedly increased testes weight, sperm quantity and motility, and attenuated testicular architecture damage. Meanwhile, WZYZP treatment significantly reversed the reduction of serum testosterone, and decreased testes malondialdehyde (MDA) and Oxidative stress index (OSI) relative to the radiated mice. Additionally, WZYZP effectively prevented the downregulation of PCNA expression in testes induced by x-ray irradiation. CONCLUSION: These findings suggest WZYZP exhibits ameliorating effects against ionizing irradiation-induced testicular damage in mice, which may be related to its antioxidation.

Development of propidium iodide as a fluorescence probe for the on-line screening of non-specific DNA-intercalators in Fufang Banbianlian Injection.

Fufang Banbianlian Injection (FBI) has been widely used as an anti-inflammatory and anti-tumor prescription. To understand the relationships between its bioactive ingredients and pharmacological efficacies, our previous study has been successfully identified some DNA-binding compounds in FBI using an established on-line screening system, in which 4',6-diamidino-2-phenylindole (DAPI) was developed as a probe. However, DAPI can be only used to screen ATT-specific DNA minor groove binders, leaving the potential active intercalators unknown in FBI. As a continuation of our studies on FBI, here we present a sensitive analytical method for rapid identification and evaluation of DNA-intercalators using propidium iodide (PI) as a fluorescent probe. We have firstly established the technique of high-performance liquid chromatography-diode-array detector-multistage mass spectrometry-deoxyribonucleic acid-propidium iodide-fluorescence detector (HPLC-DAD-MS(n)-DNA-PI-FLD) system. As a result, 38 of 58 previously identified compounds in FBI were DNA-intercalation active. Interestingly, all previously reported DNA-binders also showed intercalative activities, suggesting they are dual-mode DNA-binders. Quantitative study showed that flavonoid glycosides and chlorogenic acids were the main active compounds in FBI, and displayed similar DNA-binding ability using either DAPI or PI. In addition, 13 active compounds were used to establish the structure-activity relationships. In this study, PI was developed into an on-line method for identifying DNA-intercalators for the first time, and thus it will be a useful high-throughput screening technique for other related samples.

Rapid screening of transferrin-binders in the flowers of Bauhinia blakeana Dunn by on-line high-performance liquid chromatography-diode-array detector-electrospray ionization-ion-trap-time-of-flight-mass spectrometry-transferrin-fluorescence detection system.

Transferrin (Transferrin, TRF, TF) has drawn increasing attention in cancer therapy due to its potential applications in drug delivery. TF receptor, highly expressed in tumor cells, recognizes and transports Fe(3+)-TF into cells to release iron into cytoplasm. Thus, discovering TF-binding compounds has become an active research area and is of great importance for target therapy. In this study, an on-line analysis method was established for screening TF-binding compounds from the flowers of Bauhinia blakeana Dunn using a high-performance liquid chromatography-diode-array detector-multi-stage mass spectrometry-transferrin-fluorescence detector (HPLC-DAD-MS(n)-TF-FLD) method. As a result, 33 of 80 identified or tentatively characterized compounds in the sample were TF-binding active. Twenty-five flavonol glycosides and eight phenolic acids were identified as TF-binders. Twelve of these active compounds together with six standard compounds were used to study the dose-response effects and structure-activity relationships of flavonoids and phenolic acids. The method was validated by vitexin with a good linearity in the range of concentrations used in the study. The limit of detection for vitexin was 0.1596 nmol. Our study indicated that the established method is simple, rapid and sensitive for screening TF-binding active compounds in the extract of Bauhinia blakeana Dunn, and therefore is important for discovering potential anti-cancer ingredients from complex samples for TF related drug delivery.

[Effect of Scalp Penetration Acupuncture on the Expression of NGF in Brain Tissue around Hematoma of Intracerebral Hemorrhage Rats].

Objective To observe the effects of scalp penetration acupuncture on the expression of nerve growth factor (NGF) in brain tissue around hematoma of intracerebral hemorrhage rats. Methods To- tally 120 healthy male Wistar rats were divided into the sham-operation group, the model group, the acupunc- ture group by random digit table, 40 in each group. Rats in each group were further randomly divided into 4 time points, i.e., 6 h, 24 h, day 3, day 7. The intracerebral hemorrhage rat model was prepared by modified autologous arterial blood method, intervened by electroacupuncture (EA) at Baihui (DU20) through Taiyang (EX- HN5). Neuroethological assessment was conducted by Longa score. The expression of NGF positive cells in brain tissue around hematoma was detected using immunohistochemical method. The amount of NGF mRNA expression was measured by q-PCR. Results Compared with the sham-operation group, neurobehavioral scores increased, NGF positive cells increased, NGF mRNA expression increased in the model group at each time point, with statistical difference shown (P <0.05). Compared with the model group, 6 h neurobehavioral scores,NGF positive cells, mRNA expression of NGF did not change significantly in the acupuncture group, with no statistical difference shown (P > 0. 05). Neuroethological scores decreased, NGF positive cells increased, mRNA expression of NGF was up-regulated in the acupuncture group at 24 h, day 3 and 7, respec- tively, with statistical difference shown (P <0. 05). Conclusion scalp penetration acupuncture could up-regulate gene and protein expressions of NGF, and promote recovery of nerve function, showing favorable neuro-protective effects.

An on-line high-performance liquid chromatography-diode-array detector-electrospray ionization-ion-trap-time-of-flight-mass spectrometry-total antioxidant capacity detection system applying two antioxidant methods for activity evaluation of the edible flowers from Prunus mume.

An on-line high-performance liquid chromatography-diode-array detector-electrospray ionization-ion-trap-time-of-flight-mass spectrometry-total antioxidant capacity detection (HPLC-DAD-ESI-IT-TOF-MS-TACD) system was created for identification and evaluation of antioxidants in Prunus (P.) mume flowers. Applying this system, the HPLC fingerprint, ultraviolet (UV) spectra, mass fragmentations, active profiles against 1,1-diphenylpicryl-2-hydrazyl radical (DPPH•) scavenging activity and ferric reducing antioxidant power (FRAP) of each complex sample were obtained simultaneously after one injection. Synchronous structure identification and activities screening of complex samples were thus accomplished. In this study, 78 compounds were identified from P. mume flowers by their chromatographic behaviors, UV spectra and MS data with the assistance of standard compounds and literature reports. The DPPH and FRAP activity of 24 samples (23 different P. mume varieties and 1 related herbal medicine) were then quantified by their detailed activity profiles from the on-line system, and by the total activity of each sample extract from off-line 96-well plate method. As a result, 21 and 32 compounds in the on-line system showed anti-oxidative effects against DPPH and FRAP, respectively. The established on-line system is efficient, sensitive and reliable to tell the DPPH and FRAP antioxidant activities of individual compound in complex samples, and therefore would be a useful and promising technique for antioxidant screening from different food and medicinal matrices.

Comprehensive identification of 125 multifarious constituents in Shuang-huang-lian powder injection by HPLC-DAD-ESI-IT-TOF-MS.

A high-performance liquid chromatography-diode array detector-electrospray ionization-ion trap-time of flight-mass spectrometry (HPLC-DAD-ESI-IT-TOF-MS) method was established for excellent separation and structural identification of constituents in Shuang-huang-lian powder injection (SHLPI). The typical ultraviolet absorptions, accurate empirical molecular formula and reasonable fragmentation mechanisms of these ingredients were used for their structural elucidation. In consequence, 125 constituents (33 phenolic acids, 29 flavonoids, 32 phenylethanoid glycosides, 15 iridoid glycosides, 8 lignans, 3 amino acids and 2 purines nucleosides, 2 quinoid glycosides and 1 alkylbenzene glycoside) were either unequivocally identified or tentatively characterized by comparing authentic standards or published data. The result showed that this study could provide valuable information for the quality control and further investigation of SHLPI formula.