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1.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 4093-4096, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018898

RESUMO

In this work, we present a proof-of-concept hydrogel-based sensor system capable of wireless biochemical sensing through measuring backscattered ultrasound. The system consists of silica-nanoparticle embedded hydrogel deposited on a thin glass substrate, presenting two interfaces for backscattering (tissue/hydrogel and hydrogel/glass), which allows for system output to be invariant under the change in acoustic properties (e.g. attenuation, reflection) of the intervening biological tissue. We characterize the effect of silica nanoparticles (acoustic contrast agents) loading on the hydrogel's swelling ratio and its ultrasonic backscattering properties. We demonstrate a wireless pH measurement using dual modes of interrogations, reflection ratio and time delay. The ultrasonic hydrogel pH sensor is demonstrated with a sensing resolution of 0.2 pH level change with a wireless sensing distance around 10 cm.


Assuntos
Hidrogéis , Nanopartículas , Dióxido de Silício , Ultrassom
2.
Zootaxa ; 4845(4): zootaxa.4845.4.3, 2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-33056754

RESUMO

We describe a cryptic new species of the Cnemaspis mysoriensis complex from an isolated rocky hillock near Yadiyur, Mandya District of south Karnataka, India. Cnemaspis stellapulvis sp. nov. can be diagnosed from all other peninsular Indian congeners by its small body size (SVL <32 mm), presence of spine-like tubercles on the flanks, heterogeneous dorsal pholidosis, two or three femoral pores on each thigh separated on either side by eight poreless scales from a continuous series of two precloacal pores in males, tail with enlarged, strongly keeled, conical tubercles forming whorls, median row of sub-caudals smooth and slightly enlarged, and a distinct colour pattern. The new species can be diagnosed from members of C. mysoriensis clade by the number of femoral and precloacal pores and number of poreless scales separating these series, the number of dorsal tubercles rows at mid-body, the number of ventral scales across the belly at mid-body and subtle colour pattern differences; besides 13.4-21.4 % uncorrected ND2 sequence divergence. In this paper, we define the Cnemaspis mysoriensis clade and provide a diagnosis and comparison against peninsular Indian congeners. We also provide major diagnostic characters for members of the C. mysoriensis clade. The discovery of yet another endemic species of Cnemaspis from one of the many isolated granite rocky hills on Mysore Plateau highlights the possibilities of presence of many more cryptic undescribed species.


Assuntos
Lagartos , Distribuição Animal , Estruturas Animais , Animais , Índia , Masculino , Dióxido de Silício
3.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3399-3402, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018733

RESUMO

Parylene-C has been used as a substrate and encapsulation material for many implantable medical devices. However, to ensure the flexibility required in some applications, minimize tissue reaction, and protect parylene from degradation in vivo an additional outmost layer of polydimethylsiloxane (PDMS) is desired. In such a scenario, the adhesion of PDMS to parylene is of critical importance to prevent early failure caused by delamination in the harsh environment of the human body. Towards this goal, we propose a method based on creating chemical covalent bonds using intermediate ceramic layers as adhesion promoters between PDMS and parylene.To evaluate our concept, we prepared three different sets of samples with PDMS on parylene without and with oxygen plasma treatment (the most commonly employed method to increase adhesion), and samples with our proposed ceramic intermediate layers of silicon carbide (SiC) and silicon dioxide (SiO2). The samples were soaked in phosphate-buffered saline (PBS) solution at room temperature and were inspected under an optical microscope. To investigate the adhesion property, cross-cut tape tests and peel tests were performed. The results showed a significant improvement of the adhesion and in-soak long-term performance of our proposed encapsulation stack compared with PDMS on parylene and PDMS on plasma-treated parylene. We aim to use the proposed solution to package bare silicon chips on active implants.


Assuntos
Dióxido de Silício , Xilenos , Cerâmica , Dimetilpolisiloxanos , Humanos , Polímeros
4.
Zootaxa ; 4838(4): zootaxa.4838.4.1, 2020 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-33056800

RESUMO

Two new species of geckos from the genera Cnemaspis and Hemidactylus are described from a granite outcrop in the Rishi Valley, Chittoor District, Andhra Pradesh, India. Cnemaspis rishivalleyensis sp. nov. and Hemidactylus rishivalleyensis sp. nov. are presently known only from their type locality and are 8.7 % and 10.9 % divergent from their closest known sister species, respectively. The new species are allied to the mysoriensis and murrayi clades of South Asian Cnemaspis and the brookii group of Indian Hemidactylus, respectively. The two new species can be diagnosed from regional congeners by the number and arrangement of femoral and precloacal pores and poreless scales separating these series, body size, the number of tubercles in paravertebral rows, the number of enlarged tubercles around mid-body, the number of ventral scales across mid-body, the number of lamellae beneath digit IV of pes and manus, and subtle differences in colour pattern. Four endemic geckos now have their type localities within 10 km of each other, Cnemaspis graniticola and Cyrtodactylus rishivalleyensis from Horsley Hills and the two new species from Rishi valley. The two new species are also the third endemic species each of Cnemaspis and Hemidactylus from Andhra Pradesh.


Assuntos
Lagartos , Distribuição Animal , Animais , Ecossistema , Índia , Dióxido de Silício
5.
Zhongguo Gu Shang ; 33(8): 784-7, 2020 Aug 25.
Artigo em Chinês | MEDLINE | ID: mdl-32875773

RESUMO

As a new potential bone graft material, tissue engineered bone effectively compensates for the defects of today's bone repair materials. Meanwhile, mesoporous silica nanomaterials(MSNs) have been widely recognized due to their large specific surface area, good biocompatibility, and capability of further processing and modification. They have promising application prospects in bone tissue engineering. For the basic scientific research results that have been carried out in the early stage, the basic characteristics of mesoporous silica nano biomaterials and their application advantages, research status and development prospects in bone tissue engineering are reviewed. As for the research status, there are two aspects--as a carrier or as a component of engineering scaffolds. For the first aspect, different kinds of loaded drugs and different loading methods are reviewed. For the second, microstructure and mechanical properties of various complex scaffolds containing MSNs and the molecular and cellular behavior of seeded cells on these scaffolds are reviewed. The research of MSNs in bone cements and metal ions doped MSNs in bone tissue engineering are also included. The future development of MSNs in bone tissue engineering is also discussed.


Assuntos
Nanopartículas , Dióxido de Silício , Osso e Ossos , Porosidade , Engenharia Tecidual
6.
Waste Manag ; 118: 27-35, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32882539

RESUMO

The formation of dibenzofuran (DF), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and environmentally persistent free radicals (EPFRs) from 1,2,3-trichlorobenzene (1,2,3-TrCBz) over metal oxide / silica surface were investigated using a tubular furnace. PCDD/Fs increased exponentially from 250 to 550 °C over copper oxide / silica surface and PCDD/Fs had the maximum growth from 400 to 450 °C. The ratio of PCDD / PCDF was much less than 1, especially when the temperature raised from 450 to 550 °C. Pentachlorianated dibenzo-p-furan (PeCDF) dominated among the homologues, which contributed 45-61% to the total PCDD/Fs. Two peaks of the yield of DF occurred at 400 °C and 500 °C respectively. Furthermore, the oxygen contents have different effects for PCDD and PCDF formation, and low oxygen could promote PCDD production, especially for tetrachlorinated dibenzo-p-dioxin (TCDD). More PCDF were formed on the oxygen rich condition, indicating that the oxygen promoted the chlorination of DF. Iron oxides are better than copper oxides to catalyze the formation of PCDD/Fs from 1,2,3-TrCBzs at 350 °C, especially for PCDF. The major EPFRs on the catalysts were formed with g values in the range of 2.0040 to 2.0049, which were phenoxy radicals and semiquinone occurred with higher g value of 2.0075 when the temperature increased to 550 °C, and more EPFRs were produced with the temperature increasing. The addition of iron oxides reduced the spins concentrations of oxygen-centered radicals but increase the spins concentrations of signals with lower g values. The different possible formation pathways of PCDD and PCDF from 1,2,3-TrCBz over metal oxide surface were also proposed.


Assuntos
Dibenzodioxinas Policloradas , Benzofuranos , Clorobenzenos , Dibenzofuranos , Dibenzofuranos Policlorados , Radicais Livres , Óxidos , Dióxido de Silício
7.
Braz Oral Res ; 34: e110, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32876123

RESUMO

Acrylic resin has been used in the manufacture of prostheses, however, in the oral cavity, this material starts to retain microorganisms capable of causing gingival inflammation due its porosities. The aim of this study was to evaluate the influence of the use of silicon dioxide as a coating layer applied onto acrylic resin, on the adhesion of Candida albicans (Ca). After the incubation period in Sabouraud Dextrose Broth, a total of 1 ml of the Ca suspension was added to plate wells, each well containing a specimen of acrylic resin. The adhesion ability of Ca on acrylic resin was determined by counting colonies. Three groups (n = 6) of acrylic resin were assessed: with polishing (RP); without polishing (RW); with polishing and coating layer of silicon dioxide (RPC). Ca deposited on the surface of the acrylic resin was also observed using Scanning Electron Microscopy (SEM). Statistical assessment by Kruskal-Wallis and Student-Newman-Keuls Method were done (α = 2%). There was significant difference among the groups. The RPC group showed the lowest growth, with an average of 5.59 Log CFU/cm 2 ; there was a statistically significant difference in relation to group RW, which presented a growth of 6.07 Log CFU/cm 2 and to group RP with 5.91 Log CFU/cm 2 (p < 000.1). SEM images demonstrated that in the RP and RPC group, the surface of the resin had greater regularity, and smaller number of microorganisms. The application of silicon dioxide coating on acrylic resin appears to be a promising alternative, and its use can help in reducing the adhesion of Ca in prostheses.


Assuntos
Candida albicans , Resinas Acrílicas , Bases de Dentadura , Dióxido de Silício , Propriedades de Superfície
8.
J Biomed Nanotechnol ; 16(5): 652-658, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32919485

RESUMO

Fragrances are extensively applied in food, daily chemicals, tobacco and medicine industries. However, too strong volatility of fragrances results in a fast release rate, thereby reducing the usage time of aromatherapy products. Although loading fragrances into nanomaterials is capable of slowing their rates of release, the encapsulation efficiency of traditional nanomaterials is very low, and the nanomaterials themselves are not stable. Herein, hollow mesoporous silica nanoparticles (hMSNs) were designed for encapsulation of eugenol and the nano-fragrance was named EG@hMSNs. The structure of hMSNs was stable and the encapsulation rate of eugenol reached 46.5%. Besides, EG@hMSNs could significantly slow the release rate of eugenol. Subsequently, the EG@hMSNs were testified that they had positive roles in stress relief by open field tests. The molecular mechanisms of these positive effects on the central nervous system were then explored. Furthermore, the preparation method of hMSCs was simple, and the preparation cost was low. Therefore, EG@hMSNs are expected to be industrially produced and have a great application prospect.


Assuntos
Nanopartículas , Eugenol , Sistema Nervoso , Porosidade , Dióxido de Silício
9.
Nat Commun ; 11(1): 4535, 2020 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-32913217

RESUMO

The current understanding of the biological identity that nanoparticles may acquire in a given biological milieu is mostly inferred from the hard component of the protein corona (HC). The composition of soft corona (SC) proteins and their biological relevance have remained elusive due to the lack of analytical separation methods. Here, we identify a set of specific corona proteins with weak interactions at silica and polystyrene nanoparticles by using an in situ click-chemistry reaction. We show that these SC proteins are present also in the HC, but are specifically enriched after the capture, suggesting that the main distinction between HC and SC is the differential binding strength of the same proteins. Interestingly, the weakly interacting proteins are revealed as modulators of nanoparticle-cell association mainly through their dynamic nature. We therefore highlight that weak interactions of proteins at nanoparticles should be considered when evaluating nano-bio interfaces.


Assuntos
Nanopartículas/química , Coroa de Proteína/química , Química Click , Reagentes para Ligações Cruzadas/química , Células Endoteliais , Humanos , Poliestirenos/química , Ligação Proteica , Coroa de Proteína/análise , Dióxido de Silício/química , Células THP-1
10.
Pestic Biochem Physiol ; 170: 104696, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32980050

RESUMO

Combined application of plant essential oils (EOs) with known antimicrobial effects and silica nanocapsules with high loading capacity and protection capability of the EOs make them proper candidates for creating environmentally friendly fungicides. In this study, EOs of the Lemongrass (LGO) and Clove (CO) were used against Gaeumannomyces graminis var. tritici (Ggt), a causal agent of take-all disease of wheat. To provide controlled delivery of the EOs, they were encapsulated into mesoporous silica nanoparticles (MSNPs) and then compared to the effects of pure EOs both in- vitro and in- vivo. MSNPs were synthesized via the sol-gel process. Various techniques such as Fourier transform infrared spectroscopy (FTIR), the Brunauer-Emmett-Teller (BET), thermogravimetric analysis (TGA), and UV-Vis spectroscopy were used to evaluate the successful loading of the EOs into the pore of MSNPs. The encapsulation efficiency (EE) was calculated as high as 84.24% for LGO and 80.69% for CO, while loading efficiency (LE) was determined 36% and 29% for LGO and CO, respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) displayed spherical shapes and porous structures with average diameters of 50-70 nm. Recognition of the main components of the EOs via gas chromatographic-mass spectrometry (GC-MS) before and after the EO loading, detected eugenol and citral as the most frequent compounds in LGO and CO, respectively. For antifungal test in- vitro, selected concentrations of the pure EOs, EOs loaded in MSNPs (EOs- MSNPs) and Mancozeb ® fungicide based on pre-tests were mixed using potato dextrose agar (PDA). The inhibition percentage (IP) of fungal growth at each concentration, as well as minimum inhibition concentration (MIC) and minimum fungicidal concentrations (MFC) were obtained. The results indicated that antifungal effects in the encapsulated form increased by up to three times. In- vivo, the sterile wheat seeds were treated with pure EOs, EOs-MSNPs, and mancozeb at MFC concentration. Also, in order to keep on the EOs-MSNPs around the seeds, sodium alginate was used. The consequences of in- vivo experiments indicated that rate of disease control in presence of EOs-MSNPs and mancozeb was the same (~70%) and higher than pure EOs (LGO: 57.44%, CO: 49%). Also, improving the growth parameters in wheat plant, the covering of the EOs-MSNPs in alginate, had better control (84%) than that of EOs-MSNPs alone. Further, the release kinetics studies showed a gradual release of LGO and CO from MSNPs for four weeks in water and for five weeks in the soil-plant system. To the best of our knowledge, this is the first report of the control effect of LGO, CO, and their nanocapsule in MSNPs against the take-all disease of wheat. These results showed that the EOs-MSNPs can be a safe product for the efficient control of take-all disease in wheat crop.


Assuntos
Cymbopogon , Nanopartículas , Óleos Voláteis/farmacologia , Antifúngicos/farmacologia , Óleo de Cravo/farmacologia , Dióxido de Silício , Triticum
11.
Phytochemistry ; 177: 112452, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32773085

RESUMO

Polar lipids from the diatoms Diadesmis gallica and Navicula atomus were separated and their structures were determined using high resolution tandem MS HILIC-LC/ESI. This method allowed us to identify 34 classes of lipids, each containing dozens of molecular species, including regioisomers. The largest differences were found in two sulfur-containing lipids, sulfoquinovosyldiacylglycerol and phosphatidylsulfocholine caused probably by the remodeling of lipid species. These diatoms have been found to use several mechanisms to resolve growth in extreme environments, i.e. silica starvation. The presence of insoluble nano-SiO2 leads to the replacement of cellular phospholipids with sulfolipids. Regioisomer ratios also vary depending on the concentration of nano-SiO2 in the culture medium, i.e. the biosynthesis of polar lipids via the prokaryotic (plastidial) and/or eukaryotic (explastidial) pathways. Complex analyses of polar lipids using high resolution HILIC-LC/ESI-tandem, as used for diatoms, can also be used for other photosynthetic microorganisms.


Assuntos
Diatomáceas , Nanopartículas , Lipidômica , Dióxido de Silício , Espectrometria de Massas por Ionização por Electrospray
12.
Nat Commun ; 11(1): 3858, 2020 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-32737343

RESUMO

Checkpoint blockade therapy has provided noteworthy benefits in multiple cancers in recent years; however, its clinical benefits remain confined to 10-40% of patients with extremely high costs. Here, we design an ultrafast, low-temperature, and universal self-assembly route to integrate immunology-associated large molecules into metal-organic-framework (MOF)-gated mesoporous silica (MS) as cancer vaccines. Core MS nanoparticles, acting as an intrinsic immunopotentiator, provide the niche, void, and space to accommodate antigens, soluble immunopotentiators, and so on, whereas the MOF gatekeeper protects the interiors from robust and off-target release. A combination of MOF-gated MS cancer vaccines with systemic programmed cell death 1 (PD-1) blockade therapy generates synergistic effects that potentiate antitumour immunity and reduce the effective dose of an anti-PD-1 antibody to as low as 1/10 of that for PD-1 blockade monotherapy in E.G7-OVA tumour-bearing mice, with eliciting the robust adaptive OVA-specific CD8+ T-cell responses, reversing the immunosuppressive pathway and inducing durable tumour suppression.


Assuntos
Anticorpos Neutralizantes/farmacologia , Vacinas Anticâncer/farmacologia , Linfoma/terapia , Estruturas Metalorgânicas/farmacologia , Nanopartículas/administração & dosagem , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Animais , Antígenos de Neoplasias/administração & dosagem , Antígenos de Neoplasias/imunologia , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/imunologia , Vacinas Anticâncer/química , Citotoxicidade Imunológica , Composição de Medicamentos , Feminino , Humanos , Imunidade Inata/efeitos dos fármacos , Imunoterapia/métodos , Linfonodos/efeitos dos fármacos , Linfonodos/imunologia , Linfoma/imunologia , Linfoma/mortalidade , Linfoma/patologia , Estruturas Metalorgânicas/síntese química , Camundongos , Camundongos Endogâmicos C57BL , Nanopartículas/química , Ovalbumina/administração & dosagem , Ovalbumina/imunologia , Receptor de Morte Celular Programada 1/imunologia , Dióxido de Silício/química , Análise de Sobrevida , Carga Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
13.
Biophys Chem ; 265: 106441, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32745829

RESUMO

The possibility of immobilizing a protein with antigenic properties on a solid support offers significant possibilities in the development of immunosensors and vaccine formulations. For both applications, the orientation of the antigen should ensure ready accessibility of the antibodies to the epitope. However, an experimental assessment of the orientational preferences necessarily proceeds through the preparation/isolation of the antigen, the immobilization on different surfaces and one or more biophysical characterization steps. To predict a priori whether favorable orientations can be achieved or not would allow one to select the most promising experimental routes, partly mitigating the time cost towards the final product. In this manuscript, we apply a simple computational model, based on united-residue modelling, to the prediction of the orientation of the receptor binding domain of the SARS-CoV-2 spike protein on surfaces commonly used in lateral-flow devices. These calculations can account for the experimental observation that direct immobilization on gold gives sufficient exposure of the epitope to obtain a response in immunochemical assays.


Assuntos
Betacoronavirus/metabolismo , Epitopos/química , Modelos Moleculares , Glicoproteína da Espícula de Coronavírus/metabolismo , Antígenos/química , Antígenos/imunologia , Antígenos/metabolismo , Epitopos/imunologia , Simulação de Acoplamento Molecular , Domínios Proteicos , Dióxido de Silício/química , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/imunologia , Propriedades de Superfície
14.
Waste Manag ; 116: 166-178, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32799098

RESUMO

Platinum group metals have gained significant interest due to their unique characteristics, which make them the main constituents in advanced applications. In this work, we introduce new pH-dependent optical mesocaptors for the colorimetric monitoring and separation of Au(III) from E-waste leach liquors without a preconcentration process. The mesoporous silica nanospheres are fabricated via simple, reproducible, and low-cost procedures. The optical mesocaptor is designed via indirect immobilization of thiazole yellow G (TYG) and amacid yellow M (AYM) chromogenic probes onto mesoporous nanostructured scaffolds. The silanol groups in the mesopores of silica surface robustly anchored dilauryl dimethyl ammonium bromide (DDAB) linker to induce the interactions with the TYG and AYM chelates, thereby leading to the fashioning of a stable optical mesocaptors without releasing of the chelates throughout adsorption and sensing assays. The finding provides evidence of the capability of the synthesized decorated new nanostructured sensor shows excellent sensitivity toward Au(III) with a limit of detection (LOD) as low as 1.16 µg L-1. Furthermore, the new sensors were able to selectively detect Au(III) in solution with multi ions components.


Assuntos
Resíduo Eletrônico , Nanoporos , Adsorção , Ouro/análise , Dióxido de Silício
15.
J Environ Sci (China) ; 96: 55-63, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32819699

RESUMO

In this work, a series of Cu-ZSM-5 catalysts with different SiO2/Al2O3 ratios (25, 50, 100 and 200) were synthesized and investigated in n-butylamine catalytic degradation. The n-butylamine can be completely catalytic degradation at 350°C over all Cu-ZSM-5 catalysts. Moreover, Cu-ZSM-5 (25) exhibited the highest selectivity to N2, exceeding 90% at 350°C. These samples were investigated in detail by several characterizations to illuminate the dependence of the catalytic performance on redox properties, Cu species, and acidity. The characterization results proved that the redox properties and chemisorption oxygen primarily affect n-butylamine conversion. N2 selectivity was impacted by the Brønsted acidity and the isolated Cu2+ species. Meanwhile, the surface acid sites over Cu-ZSM-5 catalysts could influence the formation of Cu species. Furthermore, in situ diffuse reflectance infrared Fourier transform spectra was adopted to explore the reaction mechanism. The Cu-ZSM-5 catalysts are the most prospective catalysts for nitrogen-containing volatile organic compounds removal, and the results in this study could provide new insights into catalysts design for VOC catalytic oxidation.


Assuntos
Dióxido de Silício , Butilaminas , Catálise , Oxirredução , Estudos Prospectivos
16.
Int J Nanomedicine ; 15: 4779-4791, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32753866

RESUMO

Background: Considering the timeline required for the development of novel antimicrobial drugs, increased attention should be given to repurposing old drugs and improving antimicrobial efficacy, particularly for chronic infections associated with biofilms. Methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) are common causes of biofilm-associated infections but produce different biofilm matrices. MSSA biofilm cells are typically embedded in an extracellular polysaccharide matrix, whereas MRSA biofilms comprise predominantly of surface proteins and extracellular DNA (eDNA). Nanoparticles (NPs) have the potential to enhance the delivery of antimicrobial agents into biofilms. However, the mechanisms which influence the interactions between NPs and the biofilm matrix are not yet fully understood. Methods: To investigate the influence of NPs surface chemistry on vancomycin (VAN) encapsulation and NP entrapment in MRSA and MSSA biofilms, mesoporous silica nanoparticles (MSNs) with different surface functionalization (bare-B, amine-D, carboxyl-C, aromatic-A) were synthesised using an adapted Stöber method. The antibacterial efficacy of VAN-loaded MSNs was assessed against MRSA and MSSA biofilms. Results: The two negatively charged MSNs (MSN-B and MSN-C) showed a higher VAN loading in comparison to the positively charged MSNs (MSN-D and MSN-A). Cellular binding with MSN suspensions (0.25 mg mL-1) correlated with the reduced viability of both MSSA and MRSA biofilm cells. This allowed the administration of low MSNs concentrations while maintaining a high local concentration of the antibiotic surrounding the bacterial cells. Conclusion: Our data suggest that by tailoring the surface functionalization of MSNs, enhanced bacterial cell targeting can be achieved, leading to a novel treatment strategy for biofilm infections.


Assuntos
Anti-Infecciosos/farmacologia , Biofilmes , Staphylococcus aureus Resistente à Meticilina/fisiologia , Nanopartículas/química , Biofilmes/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/ultraestrutura , Testes de Sensibilidade Microbiana , Nanopartículas/ultraestrutura , Espectroscopia de Prótons por Ressonância Magnética , Dióxido de Silício/química , Vancomicina/farmacologia
17.
Nat Commun ; 11(1): 4249, 2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32843618

RESUMO

Aberrant cell cycle machinery and loss of the CDKN2A tumor suppressor locus make CDK4/6 a potential target in pancreatic ductal adenocarcinoma (PDAC). However, a vast majority of PDAC cases do not harbor a durable response to monotherapy of CDK4/6 inhibitor. Utilizing remote loading to co-encapsulate CDK4/6 inhibitor palbociclib (PAL) and an autophagy inhibitor hydroxychloroquine (HCQ), we demonstrate a ratiometrically designed mesoporous silica nanoformulation with synergistic efficacy in subcutaneous and orthotopic PDAC mouse models. The synergism is attributed to the effective intratumoral buildup of PAL/HCQ, which otherwise exhibit distinctly different circulatory and biodistribution profile. PAL/HCQ co-delivery nanoparticles lead to the most effective shrinkage of PDAC compared to various controls, including free drug mixture. Immunohistochemistry reveals that PAL/HCQ co-delivery nanoparticles trigger anti-apoptotic pathway after repetitive intravenous administrations in mice. When combined with a Bcl inhibitor, the performance of co-delivery nanoparticles is further improved, leading to a long-lasting anti-PDAC effect in vivo.


Assuntos
Autofagia/efeitos dos fármacos , Carcinoma Ductal Pancreático/tratamento farmacológico , Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Sistemas de Liberação de Medicamentos , Neoplasias Pancreáticas/tratamento farmacológico , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Modelos Animais de Doenças , Sinergismo Farmacológico , Humanos , Hidroxicloroquina/administração & dosagem , Hidroxicloroquina/química , Hidroxicloroquina/farmacologia , Camundongos , Nanopartículas/administração & dosagem , Nanopartículas/química , Piperazinas/administração & dosagem , Piperazinas/química , Piperazinas/farmacologia , Piridinas/administração & dosagem , Piridinas/química , Piridinas/farmacologia , Dióxido de Silício/administração & dosagem , Dióxido de Silício/química , Dióxido de Silício/farmacologia , Resultado do Tratamento
18.
J Oleo Sci ; 69(8): 893-905, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32759550

RESUMO

In this study, lipase from Thermomyces lanuginosus (TLL) was immobilized onto the parent and organic groups modified SBA-15, and the enzymatic properties of the obtained immobilized TLL samples were investigated. 1) Activity of SBA-15-TLL at 2862.78 ± 293.24 U/g was obtained. 2) Most of the organic groups modification favored a great improvement in activity, and higher activity over 12000 U/g was observed for N-phenylaminomethyl and phenyl group modification. 3) Most of the supported TLL showed better thermostability in air while poor in phosphate buffer, with over 80% vers less than 20% of their initial activity retained after 4 h incubation at 70℃. 4) The n-dodecyl, phenyl and N-phenylaminomethyl group functionalization decreased the sensitivity of immobilized TLL in extreme pH values. 5) The n-octyl and 2-(propoxymethyl)oxirane group modification confered the supported TLL good reusability, and over 60% of their initial activity was retained after five successive cycles of reuse.


Assuntos
Ascomicetos/enzimologia , Enzimas Imobilizadas/química , Lipase/química , Dióxido de Silício/química , Estabilidade Enzimática , Óxido de Etileno/química , Concentração de Íons de Hidrogênio , Fenômenos de Química Orgânica , Espaço Pessoal , Fosfatos
19.
J Chromatogr A ; 1627: 461372, 2020 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823089

RESUMO

This paper demonstrated the non-validity of Schultz et al. method by proving that the surface areas of n-alkanes and polar molecules strongly depend of the temperature. Consequently, the results of surface properties obtained by this method are inaccurate. Inverse gas chromatography (IGC) at infinite dilution and the dynamic contact angle (DCA) technique were used on the polytetrafluoroethylene (PTFE) fibers. DCA measurements led to the determination of the surface energy γs(T) of PTFE fibers as a function of the temperature T (Relation 6). The variations of the surface areas of n-alkanes and polar molecules versus the temperature were determined by studying the same PTFE fibers by IGC at infinite dilution. We proved that the product of the surface area a(T, Cn) (in Å2) of an alkane by the dispersive component of the surface energyγsd(T)of the solid is constant at any temperature: [Formula: see text] , where b(Cn) is a constant only depending on the carbon atom number n of n-alkane Cn. An analytical relation of the surface area of n-alkanes as a function of the temperature was obtained (equation 18). Our results highlighted the failure of Dorris-Gray method that was largely used to determine γsd of solids. This method considered the surface area a-CH2- of methylene group equal to 6 Å2 and constant for any used temperature. The obtained results proved the non-validity of Dorris-Gray method and gave the expression of a-CH2- as a function of the temperature T (Equation 20) proved the non-validity of Dorris-Gray method. The calculations of the thermal expansion coefficients of the surface area a and radius R represented by the respective derivatives da/dT and dR/dT, showed their important variations as a function of the temperature. The general expression of the surface area aX(T) of polar molecules was given as a function of the temperature (Expression 48). The large effect of the temperature on surface areas and radii of molecules was highlighted, except for toluene. The surface area of toluene was proved to remain constant whatever the temperature. Our results showed, in general, non-linear variations of the radius rX(T) of polar molecules adsorbed on PTFE fibers. However, except for chloroform, dichloromethane and diethyl ether where their thermal expansion coefficient depends on the temperature, the linearity of rX(T) was verified in the temperature interval [293 K, 353 K].


Assuntos
Cromatografia Gasosa/métodos , Modelos Moleculares , Compostos Orgânicos/análise , Temperatura , Adsorção , Alcanos/análise , Politetrafluoretileno/análise , Dióxido de Silício/química , Propriedades de Superfície
20.
J Chromatogr A ; 1627: 461382, 2020 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823094

RESUMO

A method is described for the functionalization of magnetic carbon nanotubes to recognize aristolochic acid Ⅰ and Ⅱ. 3-Glycidyloxypropyltrimethoxysilane was used as a coupling agent to immobilize adenine on a solid support. The morphology and structure of adenine-coated magnetic carbon nanotubes was investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and a vibrating sample magnetometer (VSM). The adsorption performance of the adenine-coated magnetic carbon nanotubes was evaluated via adsorption isotherms, the kinetics and selectivity tests. The adsorption capacity of the adenine-functionalized sorbent for aristolochic acid Ⅰ was determined to be 24.5 µg mg-1. By combining magnetic solid phase extraction with HPLC detection, a method was developed to enrich and detect aristolochic acids used in traditional Chinese medicine. A satisfactory recovery (92.7 - 97.5% for aristolochic acid Ⅰ and 92.6 - 99.4% for aristolochic acid Ⅱ) and an acceptable relative standard deviation (<4.0%) were obtained.


Assuntos
Adenina/química , Ácidos Aristolóquicos/isolamento & purificação , Fenômenos Magnéticos , Nanotubos de Carbono/química , Adsorção , Medicamentos de Ervas Chinesas/química , Compostos Férricos/síntese química , Compostos Férricos/química , Concentração de Íons de Hidrogênio , Cinética , Nanocompostos/química , Nanotubos de Carbono/ultraestrutura , Concentração Osmolar , Reprodutibilidade dos Testes , Dióxido de Silício/síntese química , Dióxido de Silício/química , Extração em Fase Sólida , Temperatura , Difração de Raios X
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