RESUMEN
Heterogeneous bubble nucleation is one of the most fundamental interfacial processes ranging from nature to technology. There is excellent evidence that surface topology is important in directing heterogeneous nucleation; however, deep understanding of the energetics by which nanoscale architectures promote nucleation is still challenging. Herein, we report a direct and quantitative measurement of single-bubble nucleation on a single silica nanoparticle within a microsized droplet using scanning electrochemical cell microscopy. Local gas concentration at nucleation is determined from finite element simulation at the corresponding faradaic current of the peak-featured voltammogram. It is demonstrated that the criteria gas concentration for nucleation first drops and then rises with increasing nanoparticle radius. An optimum nanoparticle radius around 10 nm prominently expedites the nucleation by facilitating the special topological nanoconfinements that consequently catalyze the nucleation. Moreover, the experimental result is corroborated by our theoretical calculations of free energy change based on the classic nucleation theory. This study offers insights into the impact of surface topology on heterogenous nucleation that have not been previously observed.
RESUMEN
Deep understanding of the bubble nucleation process is universally important in systems, from chemical engineering to materials. However, due to its nanoscale and transient nature, effective probing of nucleation behavior with a high spatiotemporal resolution is prohibitively challenging. We previously reported the measurement of a single nanobubble nucleation at a nanoparticle using scanning electrochemical cell microscopy, where the bubble nucleation and formation were inferred from the voltammetric responses. Here, we continue the study of heterogeneous bubble nucleation at interfaces by regulating the local nanostructures using silica nanoparticles with a distinct surface morphology. It is demonstrated that, compared to the smooth spherical silica nanoparticles, the raspberry-like nanoparticles can further significantly reduce the nucleation energy barrier, with a critical peak current about 23% of the bare carbon surfaces. This study advances our understanding of how surface nanostructures direct the heterogeneous nucleation process and may offer a new strategy for surface engineering in gas involved energy conversion systems.
RESUMEN
This study aimed to explore the molecular mechanism of Juanbi Qianggu Formula(JBQGF), an empirical formula formulated by the prestigious doctor in traditional Chinese medicine, in the treatment of rheumatoid arthritis based on network pharmacology and cell function experiments. The main active components and targets of JBQGF were obtained through Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP) and Encyclopedia of Traditional Chinese Medicine(ETCM), and the core targets underwent functional enrichment analysis and signaling pathway analysis. Cytoscape 3.6.0 was used to construct a visualized "active component-target-signaling pathway" network of JBQGF. After screening, nine potential pathways of JBQGF were obtained, mainly including G protein-coupled receptor signaling pathway and tyrosine kinase receptor signaling pathway. As previously indicated, the fibroblast growth factor receptor 1(FGFR1) signaling pathway was highly activated in active fibroblast-like synoviocytes(FLS) in rheumatoid arthritis, and cell and animal experiments demonstrated that inhibition of the FGFR1 signaling pathway could significantly reduce joint inflammation and joint destruction in collagen-induced arthritis(CIA) rats. In terms of the tyrosine kinase receptor signal transduction pathway, the analysis of its target genes revealed that FGFR1 might be a potential target of JBQGF for rheumatoid arthritis treatment. The biological effect of JBQGF by inhibiting FGFR1 phosphorylation was preliminarily verified by Western blot, Transwell invasion assay, and pannus erosion assay, thereby inhibiting matrix metalloproteinase 2(MMP2) and receptor activator of nuclear factor-κB ligand(RANKL) and suppressing the invasion of fibroblasts in rheumatoid arthritis and erosive effect of pannus bone. This study provides ideas for searching potential targets of rheumatoid arthritis treatment and TCM drugs through network pharmacology.
Asunto(s)
Artritis Reumatoide , Medicamentos Herbarios Chinos , Sinoviocitos , Ratas , Animales , Metaloproteinasa 2 de la Matriz/metabolismo , Farmacología en Red , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/genética , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/metabolismo , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/uso terapéutico , Artritis Reumatoide/tratamiento farmacológico , Artritis Reumatoide/genética , Transducción de Señal , Fibroblastos , Medicamentos Herbarios Chinos/uso terapéuticoRESUMEN
Trichoderma is a genus of filamentous fungi that play notable roles in stimulating plant growth after colonizing the root surface. However, the key proteins and molecular mechanisms governing this stimulation have not been completely elucidated. In this study, Trichoderma guizhouense NJAU 4742 was investigated in a hydroponic culture system after interacting with cucumber roots. The total proteins of the fungus were characterized, and the key metabolic pathways along with related genes were analyzed through proteomic and transcriptomic analyses. The roles played by the regulated proteins during the interaction between plants and NJAU 4742 were further examined. The intracellular or extracellular proteins from NJAU 4742 and extracellular proteins from cucumber were quantified, and the high-abundance proteins were determined which were primarily involved in the shikimate pathway (tryptophan, tyrosine, and phenylalanine metabolism, auxin biosynthesis, and secondary metabolite synthesis). Moreover, 15N-KNO3 labeling analysis indicated that NJAU 4742 had a strong ability to convert nitrogenous amino acids, nitrate, nitrile, and amines into ammonia. The auxin synthesis and ammonification metabolism pathways of NJAU 4742 significantly contributed to plant growth. The results of this study demonstrated the crucial metabolic pathways involved in the interactions between Trichoderma spp. and plants.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
Asunto(s)
Cucumis sativus , Trichoderma , Cucumis sativus/genética , Hypocreales , Raíces de Plantas , ProteómicaRESUMEN
Five pairs of meroterpenoid enantiomers, (±)-gancochlearols J - N (1-5), were isolated from the fruiting bodies of Ganoderma cochlear. Their structures were elucidated on the basis of 1D and 2D NMR and HRESIMS data. The absolute configurations of gancochlearols J - M (1-4) were assigned by electronic circular dichroism (ECD) calculations. Biological evaluation showed that (-)-1 and (-)-2 could inhibit renal fibrosis in TGF-ß1-induced rat kidney proximal tubular cells (NRK-52e).
Asunto(s)
Fibrosis/tratamiento farmacológico , Cuerpos Fructíferos de los Hongos/química , Ganoderma/química , Túbulos Renales Proximales/efectos de los fármacos , Terpenos/farmacología , Factor de Crecimiento Transformador beta1/antagonistas & inhibidores , Animales , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Relación Dosis-Respuesta a Droga , Fibrosis/metabolismo , Fibrosis/patología , Túbulos Renales Proximales/metabolismo , Túbulos Renales Proximales/patología , Estructura Molecular , Ratas , Estereoisomerismo , Relación Estructura-Actividad , Terpenos/química , Terpenos/aislamiento & purificación , Factor de Crecimiento Transformador beta1/metabolismoRESUMEN
Two structurally novel meroterpenoids, ganodermaones A (1) and B (2), were isolated from Ganoderma fungi (G. cochlear and G. lucidum). The structures of 1 and 2 were assigned by spectroscopic, computational, and X-ray diffraction methods. Compounds 1 and 2 represent the first examples of meroterpenoids in Ganoderma fungal species featuring with carbon migration. The plausible biosynthetic pathway for 1 was proposed. Biological evaluation showed that both 1 and 2 could inhibit renal fibrosis in TGF-ß1-induced kidney proximal tubular cells.
Asunto(s)
Ganoderma/química , Terpenos/química , Animales , Carbono/química , Carbono/metabolismo , Línea Celular , Supervivencia Celular/efectos de los fármacos , Colágeno Tipo I/metabolismo , Fibronectinas/metabolismo , Ganoderma/metabolismo , Túbulos Renales Proximales/citología , Túbulos Renales Proximales/efectos de los fármacos , Túbulos Renales Proximales/metabolismo , Espectroscopía de Resonancia Magnética , Conformación Molecular , Ratas , Terpenos/aislamiento & purificación , Terpenos/farmacología , Factor de Crecimiento Transformador beta1/farmacologíaRESUMEN
BACKGROUND: Colonization of Trichoderma spp. is essential for exerting their beneficial functions on the plant. However, the interactions between Trichoderma spp. and plant roots are still not completely understood. The aim of this study was to investigate how TgSWO affect Trichoderma guizhouense to establish themselves in the plant rhizosphere and promote plant growth. In this study, we deeply analyzed the molecular mechanism by which the functional characterization of the TgSWO by expressing different functional region deletion proteins (FRDP) of TgSWO. RESULTS: Root scanning analysis results showed that TgSWO could dramatically increase root density and promote growth. In addition, we also found that TgSWO could expand root cell walls, subsequently increase root colonization. Moreover, knockout of TgSWO mutants (KO) or overexpression of TgSWO mutants (OE) produced greatly reduced or increased the number of cucumber root, respectively. To clarify the molecular mechanism of TgSWO in plant-growth-promotion, we analyzed the ability of different FRDP to expand the root cell wall. The root cell wall architecture were considerably altered when treated by ΔCBD protein (the TgSWO gene of lacking in the CBD domain was cloned and heterologously expressed), in correlation with the present YoaJ domain of TgSWO. In contrast, neither the expansion of cell walls nor the increase of roots was detectable in ΔYoaJ protein. CONCLUSIONS: Our results emphasize the YoaJ domain is the most critical functional area of TgSWO during the alteration of cell wall architecture. Simultaneously, the results obtained in this study also indicate that TgSWO might play a plant-growth-promotion role in the Trichoderma-plant interactions by targeting the root cell wall.
Asunto(s)
Cucumis sativus/crecimiento & desarrollo , Cucumis sativus/microbiología , Proteínas Fúngicas/metabolismo , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/microbiología , Simbiosis , Trichoderma/metabolismo , Trichoderma/fisiología , Pared Celular/metabolismo , Raíces de Plantas/ultraestructura , RizosferaRESUMEN
Homeobox-containing 1 (HMBOX1) has been described as a transcription factor involved in the occurrence of some tumors, but its roles in ovarian cancer have never been reported. Here we aimed to investigate the roles of HMBOX1 on high-grade serous ovarian carcinoma (HGSOC). In this present study, HMBOX1 expression was decreased in HGSOC tissues and ovarian cancer cell lines (HO8910 and A2780) compared with ovarian surface epithelial tissues or normal human ovarian surface epithelial cell line (HOSEpiC). The cell proliferation of HOSEpiC was weaker than ovarian cancer cell lines. By altering the expression of HMBOX1 in A2780 and HOSEpiC, we demonstrated that HMBOX1 inhibited the cell proliferation and promoted the cell apoptosis. Furthermore, our study revealed that HMBOX1 downregulated the expression of anti-apoptotic proteins (Bcl-2, Bcl-xL), raised the expression of pro-apoptotic-regulated proteins (Bad, Bax), apoptotic executionior (Caspase3), and P53. In conclusion, HMBOX1 played important roles in occurrence of HGSOC through regulation of proliferation and apoptosis, which implied that HMBOX1 might serve as a new therapeutic target for HGSOC.
Asunto(s)
Cistadenocarcinoma Seroso/patología , Proteínas de Homeodominio/metabolismo , Neoplasias Ováricas/metabolismo , Neoplasias Ováricas/patología , Apoptosis/fisiología , Biomarcadores de Tumor/metabolismo , Estudios de Casos y Controles , Línea Celular Tumoral , Proliferación Celular/genética , Cistadenocarcinoma Seroso/genética , Cistadenocarcinoma Seroso/metabolismo , Regulación hacia Abajo , Femenino , Regulación Neoplásica de la Expresión Génica , Técnicas de Silenciamiento del Gen , Proteínas de Homeodominio/genética , Humanos , Neoplasias Ováricas/genéticaRESUMEN
Polymer adsorption and desorption are fundamental in many industrial and biomedical applications. Here, we introduce a new method to monitor the polymer desorption kinetics in situ based on the behavior of aggregation-induced emission. Poly(ethylene oxide) and colloidal silica (SiO2) were used as a model system. It was found that the aggregation-induced emission method could be successfully used to determine the polymer desorption kinetics, and the polymer desorption followed the first-order kinetics. It was also found that the polymer desorption rate constant decreased with the increasing molecular weight, which could be described by a power law function kd ≈ M-0.28, close to that of the adsorption rate constant.
RESUMEN
The study of polymer adsorption on colloidal particles has attracted intensive attention. In this work, we investigated polymer adsorption on substrate colloidal particles with two complementary morphologies, one of which has bulges (raspberry-like) on the surface and the other of which has holes instead (strawberry-like). Compared to the bulges, the holes on the colloidal particles were found to prevent polymer adsorption and this effect was dependent on the relative dimensions of the polymer coil and hole. This surface morphology effect was attributed mainly to the reduced polymer accessibility to the adsorption sites in holes when the hydrodynamic size of the polymer coil is larger than the hole, due to the size limiting effect. When the hydrodynamic size of the polymer coil is smaller than that of the holes, no difference in polymer adsorption was observed between raspberry-like and strawberry-like colloids. This study provides a strategy for regulating polymer adsorption on colloidal particles by adjusting the fine structures on the surface, which may be advantageous when limited chemical compositions are allowed. For example, protein adsorption on colloidal drugs may be found to be significantly reduced when colloids with surface holes are used.
RESUMEN
Centimeter-sized two-dimensional (2D) colloidal single crystals of polystyrene (PS) particles were fabricated at the water/air interface by capillary-modulated self-assembly. Different from previous reports, in this work, emulsifier was used to facilitate the stress release during 2D colloidal crystal formation by adjusting the interparticle lateral interactions. With the assistance of compressed nitrogen flow, 2D hexagonal colloidal single crystals of centimeter size were obtained under appropriate emulsifier concentrations. A new method was also developed to transfer the 2D colloidal crystals from the air/water interface to the desired substrate without obvious disturbance. This new transferring method was proven not to be sensitive to surface wettability nor curvature, thus 2D colloidal single crystals with large areas could be obtained on different kinds of substrate.
RESUMEN
Submicrometer hollow microspheres with mesoporous shells were prepared by a simple one-pot strategy. Colloidal silica particles were used as a particle stabilizer to emulsify the oil phase, which was composed of a polymerizable silicon monomer (TPM) and an inert organic solvent (PEA). The low interfacial tension between colloidal silica particles and TPM helped to form a Pickering emulsion with small droplet sizes. After the polymerization of TPM, the more hydrophobic PEA formed a liquid core, leading to a hollow structure after its removal by evaporation. BET results indicated that the shell of a hollow particle was mesoporous with a specific surface area over 400 m(2)·g(-1). With PEA as the core and silica as the shell, each resultant hollow particle had a hydrophobic cavity and an amphiphilic surface, thus serving as a good colloidal collector for hydrophobic contaminants in water.
Asunto(s)
Microesferas , Dióxido de Silicio/química , Tolueno/aislamiento & purificación , Contaminantes Químicos del Agua/aislamiento & purificación , Emulsiones , Interacciones Hidrofóbicas e Hidrofílicas , Tamaño de la Partícula , Polimerizacion , Porosidad , Propiedades de Superficie , Agua/químicaRESUMEN
Epoxy resin coated glass slides were used for colloidal particle lithography, in order to prepare well-defined 2D surface arrays. Upon the assistance of a large-sized 2D colloidal single crystal as template, centimeter-sized ordered surface arrays of bowl-like units were obtained. Systematic studies revealed that the parameters of obtained surface arrays could be readily controlled by some operational factors, such as temperature, epoxy resin layer thickness, and template particle size. With epoxy resin substituting for normal linear polymer, the height/diameter ratio of bowls in the formed surface arrays can be largely increased. With further reactive plasma etching, the parameters of ordered surface arrays could be finely tuned through controlling etching time. This study provides a facile way to prepare large-sized 2D surface arrays with tunable parameters.
RESUMEN
PURPOSE: This study aimed to evaluate the potential of astragalus polysaccharide (APS) pretreatment in enhancing the homing and anti-peritoneal fibrosis capabilities of bone marrow mesenchymal stromal cells (BMSCs) and to elucidate the underlying mechanisms. METHODS: Forty male Sprague-Dawley rats were allocated into four groups: control, peritoneal dialysis fluid (PDF), PDF + BMSCs, and PDF + APSBMSCs (APS-pre-treated BMSCs). A peritoneal fibrosis model was induced using PDF. Dil-labeled BMSCs were administered intravenously. Post-transplantation, BMSC homing to the peritoneum and pathological alterations were assessed. Stromal cell-derived factor-1 (SDF-1) levels were quantified via enzyme-linked immunosorbent assay (ELISA), while CXCR4 expression in BMSCs was determined using PCR and immunofluorescence. Additionally, a co-culture system involving BMSCs and peritoneal mesothelial cells (PMCs) was established using a Transwell setup to examine the in vitro effects of APS on BMSC migration and therapeutic efficacy, with the CXCR4 inhibitor AMD3100 deployed to dissect the role of the SDF-1/CXCR4 axis and its downstream impacts. RESULTS: In vivo and in vitro experiments confirmed that APS pre-treatment notably facilitated the targeted homing of BMSCs to the peritoneal tissue of PDF-treated rats, thereby amplifying their therapeutic impact. PDF exposure markedly increased SDF-1 levels in peritoneal and serum samples, which encouraged the migration of CXCR4-positive BMSCs. Inhibition of the SDF-1/CXCR4 axis through AMD3100 application diminished BMSC migration, consequently attenuating their therapeutic response to peritoneal mesenchyme-to-mesothelial transition (MMT). Furthermore, APS upregulated CXCR4 expression in BMSCs, intensified the activation of the SDF-1/CXCR4 axis's downstream pathways, and partially reversed the AMD3100-induced effects. CONCLUSION: APS augments the SDF-1/CXCR4 axis's downstream pathway activation by increasing CXCR4 expression in BMSCs. This action bolsters the targeted homing of BMSCs to the peritoneal tissue and amplifies their suppressive influence on MMT, thereby improving peritoneal fibrosis.
Asunto(s)
Planta del Astrágalo , Quimiocina CXCL12 , Células Madre Mesenquimatosas , Fibrosis Peritoneal , Polisacáridos , Ratas Sprague-Dawley , Receptores CXCR4 , Animales , Receptores CXCR4/metabolismo , Quimiocina CXCL12/metabolismo , Ratas , Masculino , Fibrosis Peritoneal/tratamiento farmacológico , Fibrosis Peritoneal/metabolismo , Polisacáridos/farmacología , Células Madre Mesenquimatosas/efectos de los fármacos , Modelos Animales de Enfermedad , Ciclamas/farmacologíaRESUMEN
Lytic polysaccharide monooxygenases (LPMOs) can improve the effectiveness with which agricultural waste is utilized. This study described the potent AA9 family protein MsLPMO3, derived from Morchella sextelata. It exhibited strong binding to phosphoric acid swollen cellulose (PASC), and had the considerable binding ability to Cu2+ with a Kd value of 2.70 µM by isothermal titration calorimetry (ITC). MsLPMO3 could also act on PASC at the C1 carbon via MALDI-TOF-MS results. Moreover, MsLPMO3 could boost the hydrolysis efficiency of corncob and wheat bran in combination with glycoside hydrolases. MsLPMO3 also exhibited strong oxidizing ability for 2,6-dimethoxyphenol (2,6-DMP), achieving the best Vmax value of 443.36 U·g-1 for pH 7.4 with a H2O2 concentration of 300 µM. The structure of MsLPMO3 was obtained using AlphaFold2, and the molecular docking results elucidated the specific interactions and key residues involved in the recognition process between MsLPMO3 and cellulose. Altogether, this study expands the knowledge of AA9 family proteins in cellulose degradation, providing valuable insights into the mechanisms of synergistic degradation of lignocellulose with cellulases.
Asunto(s)
Celulosa , Oxigenasas de Función Mixta , Celulosa/metabolismo , Oxigenasas de Función Mixta/metabolismo , Simulación del Acoplamiento Molecular , Peróxido de Hidrógeno/metabolismo , Polisacáridos/metabolismo , Oxidación-Reducción , Estrés OxidativoRESUMEN
OBJECTIVE: Fibroblast-like synoviocytes (FLSs) contribute to inflammation and joint damage in rheumatoid arthritis (RA). However, the regulatory mechanisms of FLSs in relapse and remission of RA remain unknown. Identifying FLS heterogeneity and their underlying pathogenic roles may lead to discovering novel disease-modifying antirheumatic drugs. METHODS: Combining single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics, we sequenced six matched synovial tissue samples from three patients with relapse RA and three patients in remission. We analyzed the differences in the transcriptomes of the FLS subsets between the relapse and remitted phases. We validated several key signaling pathways using quantitative real-time PCR (qPCR) and multiplex immunohistochemistry (mIHC). We further targeted the critical signals in vitro and in vivo using the collagen-induced arthritis (CIA) model in rats. RESULTS: Lining and sublining FLS subsets were identified using scRNA-seq. Differential analyses indicated that the fibroblast growth factor (FGF) pathway was highly activated in the lining FLSs from patients with relapse RA for which mIHC confirmed the increased expression of FGF10. Although the type I interferon pathway was also activated in the lining FLSs, in vitro stimulation experiment suggested that it was independent of the FGF10 pathway. FGF10 knockdown by small interfering RNA in FLSs significantly reduced the expression of receptor activator of NF-κB ligand. Moreover, recombinant FGF10 protein enhanced bone erosion in the primary human-derived pannus cell culture, whereas the FGF receptor (FGFR) 1 inhibitor attenuated this process. Finally, administering an FGFR1 inhibitor displayed a therapeutic effect in a CIA rat model. CONCLUSION: The FGF pathway is a critical signaling pathway in relapse RA. Targeted tissue-specific inhibition of FGF10/FGFR1 may provide new opportunities to treat patients with relapse RA.
Asunto(s)
Artritis Reumatoide , Sinoviocitos , Humanos , Ratas , Animales , Factor 10 de Crecimiento de Fibroblastos/metabolismo , Factor 10 de Crecimiento de Fibroblastos/farmacología , Factor 10 de Crecimiento de Fibroblastos/uso terapéutico , Artritis Reumatoide/tratamiento farmacológico , Artritis Reumatoide/genética , Artritis Reumatoide/metabolismo , Sinoviocitos/metabolismo , Inflamación/metabolismo , Fibroblastos/metabolismo , Recurrencia , Células Cultivadas , Proliferación Celular , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/genética , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/metabolismo , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/uso terapéuticoRESUMEN
A facile method to prepare monodisperse speckled colloids has been developed via one-step seeded polymerization from noncross-linked latex particles. It was found that both cross-linking agents in the added monomer mixture and charged initiation species are essential for the formation of speckles on composite latex particle surface in seeded polymerization. The size and number density of speckles on the surface are tunable by adjusting the concentration of surfactant. A possible mechanism for the formation of such speckled colloids has been proposed based on a series of control experiments. Speckled colloidal particles were used as substrates for the adsorption of tobacco mosaic virus, and a much stronger adsorption was observed compared to smooth particles, implying a potential application of these speckled particles in virus collection and more.
RESUMEN
Novel 3-elongated arylalkoxybenzamide derivatives were designed, synthesized and evaluated for their cell division inhibitory activity and antibacterial activity. Among them, the subseries of 3-alkyloxybenzamide derivatives exhibited greatly improved on-target activity against Bacillus subtilis and Staphylococcus aureus, and remarkably increased antibacterial activity against B. subtilis ATCC9372, penicillin-susceptible S. aureus ATCC25923, methicillin-resistant S. aureus ATCC29213 (MRSA) and penicillin-resistant S. aureus PR compared with 3-methoxybenzamide. In contrast, the subseries of 3-phenoxyaklyloxybenzamide, 3-heteroarylalkyloxybenzamide and 3-heteroarylthioalkyloxybenzamide derivatives only showed a significant improvement in on-target activity and antibacterial activity against B. subtilis ATCC9372.
Asunto(s)
Antibacterianos/síntesis química , Proteínas Bacterianas/antagonistas & inhibidores , Benzamidas/química , Proteínas del Citoesqueleto/antagonistas & inhibidores , Antibacterianos/química , Antibacterianos/farmacología , Bacillus subtilis/efectos de los fármacos , Proteínas Bacterianas/metabolismo , Benzamidas/síntesis química , Benzamidas/farmacología , Proteínas del Citoesqueleto/metabolismo , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Staphylococcus aureus/efectos de los fármacosRESUMEN
HYPOTHESIS: Except for chemical composition, surface morphology may endue colloidal nanoparticles with special interfacial behaviors, which is highly desired in certain scenarios, for example, ultra-stable Pickering emulsion for pharmaceutical applications where only limited chemicals are allowed. Herein, silica colloidal nanoparticle was chosen as a demo to illustrate a kinetically-controlled seeded growth strategy for the surface morphology regulation of colloidal nanoparticles. EXPERIMENTS: Surface chemical heterogeneity was primarily introduced to the silica seed nanoparticles by a seeded growth process in the presence of mixed silicate moieties with thermodynamical incompatibility. Then a further kinetically-controlled seeded growth step was performed to regulate the surface morphology of silica nanoparticles by promoting the selective condensation of tetraethoxysilane on the hydrophilic microdomains. FINDINGS: Upon reducing the growing rate, tetraethoxysilane hydrolysates tend to condensate on silica microdomains, resulting in the formation of raspberry-like nanoparticles. The generality of the kinetically-controlled seeded growth strategy was validated by its success on differently-sized silica seeds modified with a range of silane coupling agents. This established strategy is facile and effective for massive production of raspberry-like silica colloidal nanoparticles with precisely-designed surface morphology and size, offering an ideal platform for the investigation on the exclusive contribution of morphology to the interfacial behaviors of nanoparticles.
Asunto(s)
Nanopartículas , Propiedades de Superficie , Nanopartículas/química , Silanos , Dióxido de Silicio/químicaRESUMEN
Nanofibrous hydrogels are pervasive in load-bearing soft tissues, which are believed to be key to their extraordinary mechanical properties. Enlighted by this phenomenon, a novel reinforcing strategy for polymeric hydrogels is proposed, where polymer segments in the hydrogels are induced to form nanofibers in situ by bolstering their controllable aggregation at the nanoscale level. Poly(vinyl alcohol) hydrogels are chosen to demonstrate the virtue of this strategy. A nonsolvent-quenching step is introduced into the conventional solvent-exchange hydrogel preparation approach, which readily promotes the formation of nanofibrous hydrogels in the following solvent-tempering process. The resultant nanofibrous hydrogels demonstrate significantly improved mechanical properties and swelling resistance, compared to the conventional solvent-exchange hydrogels with identical compositions. This work validates the hypothesis that bundling polymer chains to form nanofibers can lead to nanofibrous hydrogels with remarkably enhanced mechanical performances, which may open a new horizon for single-component hydrogel reinforcement.