Synthesis and characterizations of MoS2 nanoflowers and spectroscopic study of their interaction with bovine serum albumin.

Molybdenum disulfide nanoflowers (MoS2 NFs) were prepared by hydrothermal method. The prepared MoS2 NFs was characterized by SEM, TEM, XRD, specific surface areas, Raman and XPS. The characterization results show that the flower-like spherical MoS2 is composed of many ultra-thin nanosheets with an average diameter of about 300-400 nm. MoS2 NFs also exhibits excellent absorption and high fluorescence intensity. In order to explore the biological behavior of MoS2 NFs, the interaction between MoS2 NFs and bovine serum albumin (BSA) was studied by UV-Vis absorption, fluorescence, synchronous fluorescence spectra, and cyclic voltammetry. The results of absorption and fluorescence show that MoS2 NFs and BSA interact strongly through the formation of complexes. The Stern-Volmer constant and the quenching constant was calculated about 3.79×107 L mol-1 and 3.79×1015 L mol-1 s-1, respectively. The synchronous fluorescence implied that MoS2 in the complex may mainly bind to tryptophan residues of BSA. The cyclic voltammograms indicated that the addition of BSA makes electron reduction of MoS2 NFs more difficult than the corresponding free state. These experimental results clarified the effective transportation and elimination of MoS2 NFs in the body by binding to BSA, and can provide useful guideline for estimating MoS2 NFs as a drug carrier.

One-pot preparation of supramolecularly functionalized silver nanoparticles for surface plasmon resonance based dual-modal sensing of phytotoxic polychlorinated biphenyl.

Polychlorinated biphenyls (PCBs), as a member of persistent organic pollutants (POPs), have posed a risk to humans and the environment until today. The monitoring of phytotoxic PCB which is toxic to plants, is especially important for ecological early warning and pollution management. In this work, ß-cyclodextrin modified silver nanoparticles are prepared in a one-pot method, integrating the synthesis and surface modification in one step. The nanoparticles can supramolecularly immobilize 2,4,4'-trichlorobiphenyl (PCB 28) on their surface and construct a surface plasmon resonance-based nanosensor. Surface plasmon-resonance light scattering and surface-enhanced Raman scattering sensing of PCB 28 are realized using the nanosensor. The dual-modal sensing shows excellent performance for the potential practical monitoring of phytotoxic POPs in the plant and its growing environment.

Integration of solid-phase microextraction and surface-enhanced Raman spectroscopy for in-vivo screening of polybrominated diphenyl ether.

The monitoring of polybrominated diphenyl ethers (PBDEs) is of great significance owing to their high persistence, bioaccumulation, and toxicity to humans and animals. In this study, a sensitive and reproducible probe that integrates solid-phase microextraction and surface-enhanced Raman spectroscopy (SPME-SERS) was developed for screening PBDEs in multiphase specimens, including live fish, water, and electrical products. A roughed Cu fiber with an Ag layer was fabricated with dual functions. BDE-15 was readily extracted and detected on the SPME-SERS probe consisting of propanethiol-modified Ag nanoplates on a Cu wire. A clear linear relationship (R2 = 0.988) was established between the SERS intensity at 782 cm-1 and the logarithmic concentrations (from 100 ppb to 100 ppm), with a detection limit of 15 ppb. This proposed method enables continuous in vivo monitoring in fish without complicated pretreatments. The results obtained by this SPME-SERS approach were validated by high-performance liquid chromatography and showed good agreement. This "extracting and detecting" SPME-SERS method provides a potential tool to monitor the occurrence, formation, and migration of PBDEs.

Three-dimensional nanorod array for label-free surface-enhanced Raman spectroscopy analysis of microRNA pneumoconiosis biomarkers.

Novel approaches are required to overcome the challenges associated with conventional microRNA (miRNA) detection methods and realize the early diagnosis of diseases. This work describes a novel label-free surface-enhanced Raman spectroscopy (SERS) method for the detection of the miRNA biomarkers for pneumoconiosis on a three-dimensional Au-coated ZnO nanorod array (Au-ZnO NRA). The Au-ZnO NRA substrate, which was fabricated via a modified seeding method combined with ion sputtering, provided a high enhancement factor and good spatial uniformity of the signal. With the Au-ZnO NRA, the SERS spectra of miRNAs were obtained in 30 s without labeling at room temperature. Density functional theory calculations were performed to understand the structural fingerprints of the miRNAs. Principal component analysis was carried out to identify the pneumoconiosis biomarkers based on their fingerprint SERS signals. Dual-logarithm linear relationships between the SERS intensity and the miRNA concentration were proposed for quantitative analysis. The label-free SERS method has limits of detection on the femtomolar level, which is much lower than the concentrations of the miRNA biomarkers for pneumoconiosis in lung fibroblasts.

Acupuncture Enhances Dorsal Raphe Functional Connectivity in Knee Osteoarthritis With Chronic Pain.

INTRODUCTION: Knee osteoarthritis is a common disease in the elderly. Patients suffer from long-term chronic pain and reduced life quality. Acupuncture has been proven to be an effective treatment for KOA. However, the neural mechanism of acupuncture is unclear, so far. Periaqueductal gray (PAG) and raphe nuclei (RPN) are essential structures associated with chronic pain in human brains. This study aims to investigate functional connectivity (FC) changes of PAG and RPN in KOA to interpret the neural mechanism of acupuncture. METHODS: In 15 patients with KOA and 15 healthy controls (HC), we acquired Visual Analog Scale (VAS) scores and resting-state fMRI images of each participant before and after acupuncture stimulation on EX-LE5 acupoint. Then, PAG and RPN were selected as seeds to perform FC analysis based on resting-state fMRI images. Finally, we compared FC patterns of PAG and RPN between patients with KOA and HC, then between pre-acupuncture and post-acupuncture. Correlations between FC values and VAS scores were calculated as well. RESULTS: For PAG, FC of patients with KOA was lower in the right lingual gyrus at post-acupuncture compared with HC (p <0.001, uncorrected). For dorsal RPN, FC of patients with KOA was significantly higher in right putamen at post-acupuncture compared with HC (p <0.001, corrected with FDR), and FC changes were significant between pre-acupuncture and post-acupuncture in patients with KOA. Post-acupuncture FC values between dorsal RPN and right putamen were correlated with VAS scores. For medial RPN, FC of patients with KOA was lower in the right cerebellum at post-acupuncture compared with HC (p <0.001, uncorrected), but no significant FC changes were found between pre-acupuncture and post-acupuncture in patients with KOA. FC values between medial RPN and right cerebellum were not correlated with VAS scores at pre-acupuncture and post-acupuncture. DISCUSSION: Our study demonstrated that acupuncture enhanced FC between dorsal RPN and the right putamen in patients with KOA, which was associated with chronic pain intensity. This result suggests that acupuncture stimulation can enhance FC between dorsal raphe and striatum, illustrating a neural mechanism that acupuncture can drive the patients' brain, with KOA, to perceive pain.

A novel colorimetric and fluorescent probe based on a core-extended perylene tetra-(alkoxycarbonyl) derivative for the selective sensing of fluoride ions.

A novel fluoride (F-) colorimetric and fluorescent probe (P1) based on a core-extended perylene tetra-(alkoxycarbonyl) (PTAC) derivative was developed. The probe exhibited high sensitivity and selectivity for distinguishing F- from other common anions through significant changes of the UV-Vis and fluorescence spectra. Job's plot analysis revealed that the stoichiometry of the P1-F- interaction is 1 : 1. The association constant between P1 and F- was estimated to be 9.7 × 102 M-1 and the detection limit of F- was about 0.97 µM. An approximately 76 nm red-shift in the absorption and fluorescent quenching response was observed when F- was associated with P1. The emission intensity (I 574) decreased linearly along with the F- concentration from 3 × 10-5 M to 2 × 10-4 M. The mechanism of intermolecular proton transfer (IPT) was deduced based on the changes in the absorption, fluorescence, electrochemistry, and 1H NMR titration spectra. The density functional theory (DFT) theoretical results of the P1-F- complex are in good agreement with the experimental results. The rapid detection of F- ions in the solid state and living cells was also studied.

[Effects of huayu tongluo moxibustion on learning and memory ability and the hippocampal BDNF/TrkB expressions in the rats of vascular dementia].

OBJECTIVE: To explore the effects of huayu tongluo (resolving stasis, promoting collateral circulation) moxibustion on learning and memory ability and the expressions of brain derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB) in the rats of vascular dementia (VD) in the microenvironment of neurovascular niche. METHODS: Using 2-vessel occlusion (2-VO), the VD rat models were duplicated. The neural stem cells (NSCs) labeled with lentiviral vector-mediated enhanced green fluorescent protein (EGFP) were co-cultured with endothelial progenitor cells (EPCs) to structure the NSCs + EPCs implant. The implant was transplanted into the lateral ventricle of VD rats and the VD rat models with neurovascular niche were established. In No.1 experiment, the successful-modeled rats were divided into 3 groups, i.e. a NSCs + EPCs moxibustion group, a NSCs + EPCs blank group and a model group, 12 rats in each one. No any treatment was provided in the model group and the NSCs + EPCs blank group. The huayu tongluo moxibustion therapy was adopted in the NSCs + EPCs moxibustion group, in which, the suspending moxibustion technique was applied to "Baihui" (GV 20), "Dazhui" (GV 14) and "Shenting" (GV 24), 20 min at each acupoint. The treatment was given once every day and a 14-day treatment was as one course. Totally, 3 courses of treatment were required. At the end of treatment, Morris water maze experiment was adopted to determine the learning and memory ability of the rats in each group. In the No.2 experiment, the model rats were divided into 3 groups, a NSCs + EPCs moxibustion group, a NSCs + EPCs blank group and a model group, 18 rats in each one. In each group, according to the durations of treatment, 3 subgroups were divided and 6 rats in each one. The intervention method was same as the No.1 experiment. Additionally, after corresponding treatment course, using perfusion, the brains were collected in each subgroup and the slices were frozen. BDNF/TrkB expressions were observed in the immunofluorescence test. RESULTS: After treatment, in the NSCs + EPCs moxibustion group, the escape incubation was reduced, the time of the first running-cross platform was shortened and the frequency of running-cross platform increased as compared with the model group and the NSCs + EPCs blank group (P<0.01, P<0.05). The protein expressions were increased in tendency among the 3 courses of treatment in the NSCs + EPCs moxibustion group, indicating the significant differences (all P<0.05), in which, the increase of the protein expressions in the NSCs + EPCs moxibustion group was better than the NSCs + EPCs blank group (P<0.05, P<0.01). CONCLUSION: The huayu tongluo moxibustion therapy is the effective approach to VD in clinical treatment. This therapy up-regulates the BDNF/TrkB protein expressions in the microenvironment of neurovascular niche, co-modulates NSCs-EPCs coupling mechanism, promotes nerve neogenesis and repairs the injured nerve.

Galvanic displacement-induced codeposition of reduced-graphene-oxide/silver on alloy fibers for non-destructive SPME@SERS analysis of antibiotics.

This work describes the integration of solid-phase microextraction (SPME) and surface-enhanced Raman spectroscopy (SERS) by codeposition of a hybrid consisting of reduced graphene oxide and silver on silver-copper alloy fibers. The morphology and structure of the coating were characterized by a variety of microscopic and spectroscopic techniques that confirmed the hybrid structure of the material. A galvanic-displacement-induced process is assumed to be involved during the codeposition of the hybrid coating on the alloy. In this process, Ag(I) is reduced to Ag(0) by Cu(0), and the presence of conjugated domains in GO facilitates the long-range transfer of electrons from Cu to Ag+. Simultaneously, GO accepts electrons and is converted into RGO. The hybrid coating exhibits a high SERS enhancement factor and good spatial uniformity. The needle-like coated alloy fibers are shown to be a viable tool for non-destructive sampling and SERS-based determination of trace levels of the antibiotics sulfadiazine and sulfamethoxazole in a spiked tissue mimic. The SERS peaks at 1149 cm-1 for sulfadiazine and 1144 cm-1 for sulfamethoxazole are selected as the reference peaks in the quantitative analysis. The linear range is from 0.01 to 100 µg·cm-3. The detection limits are 1.9 ng·cm-3 for sulfadiazine and 4.4 ng·cm-3 for sulfamethoxazole. Graphical abstract Schematic presentation of I: Galvanic-displacement-induced reduction of graphene oxide (brown films) and Ag+ (purple dots) on silver-copper alloy; II: Codeposition of reduced-graphene-oxide (grey films)/Ag (blue stars) on alloy fiber; III: Non-destructive SPME of antibiotics from spiked tissue mimic; IV: SERS detection using Raman spectroscope.

[Effect of Moxibustion on Delayed Memory and Expression of Hippocampal Nestin and Doublecortin Proteins in Dementia Rats].

OBJECTIVE: To observe the effect of "Huayu Tongluo"(Blood-stasis Dispersing and Meridian-collateral Dredging) moxibustion on the delayed memory and expression of Nestin and Doublecortin (DCX) proteins in the hippocampus in vascular dementia (VD) rats in the view of neurogenesis produced by intracerebral transplantation of neural stem cells (NSCs) and endothelial progenitor cells (EPCs). METHODS: Healthy male Wistar rats were randomized into control group, VD model group,NSCs＋EPCs group and NSCs＋EPCs moxibustion group. The VD model was established by using a modified 2-vessels occlusion method, and neurogenesis was produced by transplantation of NSCs＋EPCs (2×106cell/10 µL) into the lateral ventricle for rats of the NSCs＋EPCs groups 3 days after successful VD-modeling. Moxibustion was applied to "Dazhui" (GV 14), "Baihui" (GV 20) and "Shenting" (GV 24) once daily for 21 days with an interval of one day between every two 7 days. The Morris Water Maze was used to test the rat's delayed memory ability before and 24 h after the treatment. The expression of Nestin and DCX proteins in the hippocampus tissues was detected using double-labeled immunofluorescence technique. RESULTS: Following modeling, Morris Water Maze tests showed that the average escape latency of location navigation task was significantly prolonged in VD rats(P<0.008)and the times of target platform crossing (spatial probing task) within 120 s were remarkably reduced in VD rats (P<0.008). Compared with pre-treatment in the same one group, the escape latency of NSCs＋EPCs and NSCs＋EPCs moxibustion groups were considerably reduced (P<0.05), and the average times of target platform crossing of the NSCs＋EPCs moxibustion group were markedly increased(P<0.05). The effect of NSCs＋EPCs moxibustion was evidently superior to that of simple NSCs＋EPCs in shortening the escape latency (P<0.008). The expression levels of Nestin protein were significantly higher in the NSCs＋EPCs moxibustion group after 1 and 3 period treatment than those in the NSCs＋EPCs group (P<0.05)．. CONCLUSION: Moxibustion intervention is able to improve the delayed memory in VD rats, which may be related to its effect in up-regulating the expression of hippocampal Nestin and DCX proteins within 15 days via accelerating neurogenesis.

Au-coated ZnO nanorods on stainless steel fiber for self-cleaning solid phase microextraction-surface enhanced Raman spectroscopy.

Solid phase microextraction-surface enhanced Raman spectroscopy (SPME-SERS), combining the pretreatment and determination functions, has been successfully used in environmental analysis. In this work, Au-coated ZnO nanorods were fabricated on stainless steel fiber as a self-cleaning SERS-active SPME fiber. The ZnO nanorods grown on stainless steel fiber were prepared via a simple hydrothermal approach. Then the obtained nanostructures were decorated with Au nanoparticles through ion-sputtering at room temperature. The obtained SERS-active SPME fiber is a reproducible sensitivity sensor. Taking p-aminothiophenol as the probe molecule, the RSD value of the SERS-active SPME fiber was 8.9%, indicating the fiber owned good uniformity. The qualitative and quantitative detection of crystal violet and malachite green was also achieved. The log-log plot of SERS intensity to crystal violet and malachite green concentration showed a good linear relationship. Meanwhile, this SERS-active SPME fiber can achieve self-cleaning owning to the excellent photocatalytic performance of ZnO nanorods. Crystal violet was still successfully detected even after five cycles, which indicated the high reproducibility of this SERS-active SPME fiber.

Silver nanoparticle aggregates on metal fibers for solid phase microextraction-surface enhanced Raman spectroscopy detection of polycyclic aromatic hydrocarbons.

Solid phase microextraction (SPME), a solvent free technique for sample preparation, has been successfully coupled with GC, GC-MS, and HPLC for environmental analysis. In this work, a method combining solid phase microextraction with surface enhanced Raman spectroscopy (SERS) is developed for detection of polycyclic aromatic hydrocarbons (PAHs). Silver nanoparticle aggregates were deposited on the Ag-Cu fibers via layer-by-layer deposition, which were modified with propanethiol (PTH). The SERS-active SPME fiber was immersed in water directly to extract PAHs and then detected using a portable Raman spectrometer. The pronounced valence vibration of the C-C bond at 1030 cm(-1) was chosen as an internal standard peak for the constant concentration of PTH. The RSD values of the stability and the uniformity of the SERS-active SPME fiber are 2.97% and 5.66%, respectively. A log-log plot of the normalized SERS intensity versus fluoranthene concentration showed a linear relationship (R(2) = 0.95). The detection limit was 7.56 × 10(-10) M and the recovery rate of water samples was in the range of 95% to 115%. The method can also be applied to detection of PAH mixtures, and each component of the mixtures can be distinguished by Raman characteristic peaks. The SERS-active SPME fiber could be further confirmed by GC-MS.

Silver nanoplate-decorated copper wire for the on-site microextraction and detection of perchlorate using a portable Raman spectrometer.

Perchlorate, which causes health concerns because of its effects on the thyroid function, is highly soluble and mobile in the environment. In this study, diethyldithiocarbamate (DDTC)-modified silver nanoplates were fabricated on a copper wire to perform the on-site microextraction and detection of perchlorate. This fiber could be inserted into water or soil to extract perchlorate through electrostatic interaction and then can be detected by a portable Raman spectrometer, owing to its surface-enhanced Raman (SERS) activity. A relatively stable vibrational mode (δ(HCH)(CH3), (CH2)) of DDTC at 1273 cm(-1) was used as an internal standard, which was negligibly influenced by the absorption of ClO4(-). The DDTC-modified Ag/Cu fiber showed high uniformity, good reusability and temporal stability under continuous laser radiation each with an RSD lower than 10%. The qualitative and quantitative detection of perchlorate were also realized. A log-log plot of the normalized SERS intensity against perchlorate concentration showed a good linear relationship. The fiber could be also directly inserted into the perchlorate-polluted soil, and the perchlorate could thereby be detected on site. The detection limit in soil reached 0.081 ppm, which was much lower than the EPA-published safety standard. The recovery of the detection was 105% and comparable with the ion chromatography. This hyphenated method of microextraction with direct SERS detection may find potential application for direct pollutant detection free from complex sample pretreatment.

Combination of solid phase extraction and surface-enhanced Raman spectroscopy for rapid analysis.

A surface-enhanced Raman spectroscopy (SERS)-active extraction column based on propanethiol modified silver dendrites was fabricated. The column, which combines the advantages of solid phase extraction and SERS, may facilitate the development of rapid analysis with high reliability and accuracy. High temporal stability (under a continuous and intensive laser radiation) and excellent repeatability (repeated extraction and elution) were also achieved using this column. As an example, the quantitative analysis of fluoranthene was accomplished in the concentration range of 0.01-100 µg mL(-1) with this column. The extraction process could be accomplished in 10 s and the total time of one sample analysis including extraction, spectral acquisition, elution and intermediate process could be less than 30 s. This method can greatly simplify the sample preparation and reduce the total analysis time.