壳聚糖基金纳米棒自组装纳米球的制备与表征

目的 通过壳聚糖衍生物表面的巯基与金元素形成非常强的Au-S键,制备表面带有金纳米棒(GNRs)的自组装纳米球CS-GNRs.方法 用透射电子显微镜观察自组装纳米球的形貌特征,动态激光粒度分析仪检测其粒度分布,紫外-可见分光光度计检测其光学特性及其性质改变,同时对其表面增强拉曼光谱(SERS)效应进行检测.结果 该纳米球形态良好、粒径均一、分散性好,并且结晶紫(CV)在壳聚糖纳米金杂化纳米球表面的拉曼增强因子可达2×103.结论 该纳米球在分子检测和拉曼光谱效应检测方面具有潜在的应用价值.     

An inhibitory effect of resveratrol in the mitotic clonal expansion and insulin signaling pathway in the early phase of adipogenesis

Resveratrol is known as a potent antiobesity compound that acts partly through inhibition of adipogenesis. However, the direct targets responsible for its antiadipogenic action are unclear. Our hypothesis is that resveratrol inhibits adipogenesis through modulation of mitotic clonal expansion (MCE) and cell signaling pathways in the early phase of differentiation. To test this, we examined the effects of resveratrol on MCE and insulin signaling pathway in the early phase of adipogenesis in murine preadipocytes. We observed that the antiadipogenic action of resveratrol is largely limited to the early phase of adipogenesis. Specifically, the presence of resveratrol in the first 24 hours of adipogenesis was required for its antiadipogenic effect. During the first 24 hours of adipogenesis, resveratrol impaired the progression of MCE by suppressing the cell cycle entry of preadipocytes to G2/M phase, and expression of cell cycle regulators cyclin A and cyclin-dependent kinase 2. Concomitantly, resveratrol inhibited insulin signaling pathway in the early phase of adipogenesis. Furthermore, we revealed an inhibitory effect of resveratrol on insulin receptor (IR) activity, and this is likely through a direct physical interaction between resveratrol and IR. The antiadipogenic effect of resveratrol is through inhibition of the MCE and IR-dependent insulin signaling pathway in the early phase of adipogenesis.     

Homozygous WASHC4 variant in two sisters causes a syndromic phenotype defined by dysmorphisms,intellectual disability,profound developmental disorder,and skeletal muscle involvement

Recessive variants in WASHC4 are linked to intellectual disability complicated by poor language skills, short stature, and dysmorphic features. The protein encoded by WASHC4 is part of the Wiskott–Aldrich syndrome protein and SCAR homolog family, co-localizes with actin in cells, and promotes Arp2/3-dependent actin polymerization in vitro. Functional studies in a zebrafish model suggested that WASHC4 knockdown may also affect skeletal muscles by perturbing protein clearance. However, skeletal muscle involvement has not been reported so far in patients, and precise biochemical studies allowing a deeper understanding of the molecular etiology of the disease are still lacking. Here, we report two siblings with a homozygous WASHC4 variant expanding the clinical spectrum of the disease and provide a phenotypical comparison with cases reported in the literature. Proteomic profiling of fibroblasts of the WASHC4-deficient patient revealed dysregulation of proteins relevant for the maintenance of the neuromuscular axis. Immunostaining on a muscle biopsy derived from the same patient confirmed dysregulation of proteins relevant for proper muscle function, thus highlighting an affliction of muscle cells upon loss of functional WASHC4. The results of histological and coherent anti-Stokes Raman scattering microscopic studies support the concept of a functional role of the WASHC4 protein in humans by altering protein processing and clearance. The proteomic analysis confirmed key molecular players in vitro and highlighted, for the first time, the involvement of skeletal muscle in patients. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.     

Molecular analysis of the destruction of articular joint tissues by Raman spectroscopy

ABSTRACT

Introduction

Osteoarthritis (OA) is a highly heterogenous disease influenced by different molecular, anatomic, and physiologic imbalances. Some of the bottlenecks for enhanced diagnosis and therapeutic assessment are the lack of validated biomarkers and early diagnosis tools. In this narrative review, we analyze the potential of Raman spectroscopy (RS) as a label-free optical tool for the characterization of articular joint tissues and its application as a diagnosis tool for OA.     

Influence of Deposition Method on the Structural and Optical Properties of Ge2Sb2Te5

Ge2Sb2Te5 (GST-225) is a chalcogenide material with applications in nonvolatile memories. However, chalcogenide material properties are dependent on the deposition technique. GST-225 thin films were prepared using three deposition methods: magnetron sputtering (MS), pulsed laser deposition (PLD) and a deposition technique that combines MS and PLD, namely MSPLD. In the MSPLD technique, the same bulk target is used for sputtering but also for PLD at the same time. The structural and optical properties of the as-deposited and annealed thin films were characterized by Rutherford backscattering spectrometry, X-ray reflectometry, X-ray diffraction, Raman spectroscopy and spectroscopic ellipsometry. MS has the advantage of easily leading to fully amorphous films and to a single crystalline phase after annealing. MS also produces the highest optical contrast between the as-deposited and annealed films. PLD leads to the best stoichiometric transfer, whereas the annealed MSPLD films have the highest mass density. All the as-deposited films obtained with the three methods have a similar optical bandgap of approximately 0.7 eV, which decreases after annealing, mostly in the case of the MS sample. This study reveals that the properties of GST-225 are significantly influenced by the deposition technique, and the proper method should be selected when targeting a specific application. In particular, for electrical and optical phase change memories, MS is the best suited deposition method.     

Development and Characterization of Fe3O4@Carbon Nanoparticles and Their Biological Screening Related to Oral Administration

The current study presents the effect of naked Fe₃O₄@Carbon nanoparticles obtained by the combustion method on primary human gingival fibroblasts (HGFs) and primary gingival keratinocytes (PGKs)—relevant cell lines of buccal oral mucosa. In this regard, the objectives of this study were as follows: (i) development via combustion method and characterization of nanosized magnetite particles with carbon on their surface, (ii) biocompatibility assessment of the obtained magnetic nanoparticles on HGF and PGK cell lines and (iii) evaluation of possible irritative reaction of Fe₃O₄@Carbon nanoparticles on the highly vascularized chorioallantoic membrane of a chick embryo. Physicochemical properties of Fe₃O₄@Carbon nanoparticles were characterized in terms of phase composition, chemical structure, and polymorphic and molecular interactions of the chemical bonds within the nanomaterial, magnetic measurements, ultrastructure, morphology, and elemental composition. The X-ray diffraction analysis revealed the formation of magnetite as phase pure without any other secondary phases, and Raman spectroscopy exhibit that the pre-formed magnetic nanoparticles were covered with carbon film, resulting from the synthesis method employed. Scanning electron microscopy shown that nanoparticles obtained were uniformly distributed, with a nearly spherical shape with sizes at the nanometric level; iron, oxygen, and carbon were the only elements detected. While biological screening of Fe₃O₄@Carbon nanoparticles revealed no significant cytotoxic potential on the HGF and PGK cell lines, a slight sign of irritation was observed on a limited area on the chorioallantoic membrane of the chick embryo.     

Glass-ionomer and calcium silicate-based cements interactions with human dentine in health and disease: Two-photon fluorescence microscopy and Raman spectroscopy analysis.

ObjectivesTo investigate the potential mineralising effects of calcium silicate-based dentine replacement material (Biodentine?) in comparison with glass-ionomer cement (GIC) (Fuji IX?) on different human dentine substrates using a multimodal non-invasive optical assessment.MethodsCements were applied on artificially demineralised or naturally carious dentine and stored for 4 weeks in phosphate-rich media +/- tetracycline used for mineralisation labelling. Interfacial dentine was examined from the same sample and location before and after aging using two-photon fluorescence microscopy, fluorescence lifetime imaging (FLIM) and second harmonic generation (SHG) imaging. Additionally, Raman spectroscopy was used to detect changes in the mineral content of dentine.ResultsSignificant changes in the fluorescence intensity and lifetime were detected in partially demineralised dentine and caries-affected dentine underneath both tested cements, after storage (p < 0.001). This was associated with a significant increase in the mineral content as indicated by the increased intensity of the phosphate Raman peak located at 959 cm^?1 (p < 0.0001). Caries-infected dentine showed significant fluorescence changes under Biodentine? after storage (p < 0.001), but not under GIC (p = 0.44). Tetracycline binding induced a reduction in the fluorescence lifetime with comparable increase in the fluorescence intensity in both cements’ groups within the affected dentine (p < 0.001). SignificanceTwo-photon fluorescence microscopy can be used efficiently for non-destructive in-vitro dentine caries characterisation providing a technique for studying the same dentine-cement interface over time and detect changes. Biodentine? demonstrated comparable remineralising potential to GIC, in addition to inducing remineralisation of caries-infected dentine. This may suggest using Biodentine? as part of minimally invasive operative dentistry (MID) in caries management.     

基于重水拉曼技术的氯己定对白色念珠菌 抑菌效能的研究

目的评价重水拉曼技术的普适性及氯己定(CHX)对白色念珠菌的抑菌效能。方法1)采用分光光度计测定吸光度值OD600,重水拉曼技术测定C?D ratio(重水峰所占比例)随时间的变化,探索重水对白色念珠菌生长的影响及该菌对重水的吸收规律,以评价重水拉曼技术的普适性。2)采用肉汤稀释法和重水拉曼技术,测定CHX对白色念珠菌的最低抑菌浓度(MIC)及最小代谢活性抑制浓度(MIC?MA),评价CHX对白色念珠菌生长及代谢的抑制效果。结果1)白色念珠菌在质量分数≤30%重水中,生长未受到明显抑制(P>0.05);白色念珠菌能活跃代谢重水并通过拉曼图谱检测,且C?D ratio与重水质量分数呈线性正相关关系(R^2=0.9894,P<0.05)。2)CHX对白色念珠菌的MIC为4μg·mL^-1,MIC?MA为8μg·mL^-1。在MIC下,白色念珠菌的生长受到完全抑制,但仍具有很高的代谢活性;只有达到2×MIC,即MIC?MA,该菌的代谢才能得到完全抑制。结论重水拉曼技术适用于评价药物对真菌代谢活性的影响,临床常用质量分数的CHX可完全抑制白色念珠菌的生长及代谢。     

A Scalable Route to Highly Functionalized Multi‐Walled Carbon Nanotubes on a Large Scale

A scalable and solvent‐free chemical process to obtain highly functionalized and dispersible multi‐walled carbon nanotubes is reported. Highly functionalized multi‐walled carbon nanotubes have been prepared using in situ generated aryl diazonium salts in the presence of ammonium persulfate and 2,2′‐azoisobutyronitrile by solvent‐free techniques. In the Raman spectra of the resulting materials, characteristic peaks, the D‐ and G‐bands, are shifted by about 10 cm^?1 to lower frequencies. At the same time, the relative intensity ratios between the D‐ and G‐bands increase in comparison to that in the spectrum of the purified product. Fourier‐transform infrared spectroscopy reveals the presence of the functional groups on the surface. Transmission electron microscopy images directly confirm the significant build‐up of sidewall organic moieties on the treated materials. The weight loss of various functional moieties determined by thermogravimetry–differential scanning calorimetry analysis is about 18–33%. The dispersibility of the functionalized materials in solvents, such as chloroform, tetrahydrofuran, and water, is obviously improved.