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1.
Chemosphere ; 286(Pt 2): 131734, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34352545

RESUMO

Silane/ceramic combination provides the composites with several advantages from the advancements of new ceramic composite materials with good thermal conductivity, high mechanical and dielectric properties have wide significant applications in electrical and electronic industries. In this study, to enhance the dispersibility of dielectric barium titanate (BaTiO3) ceramic powder and additives for the fabrication of multilayer ceramic capacitors (MLCCs), surface treatment of the precursor of ceramic powder was performed using silane coupling agents. Dielectric ceramic sheets fabricated from ceramic powders that had been surface-treated with different amounts of N-[3-(trimethoxysilyl)propyl]aniline (TMSPA) which increased the surface gloss. In particular, the dielectric properties of the multilayer ceramic sheet fabricated by stacking sheets from the TMSPA-treated ceramic powder sintering at 1200 °C, it was confirmed that the dielectric constant increased from 881 to 2382 and the dielectric loss dropped from 1.96 to 1.34% with utilization of the TMSPA treatment. The physical and dielectric properties of the TMSPA-treated multilayer ceramic sheet were also determined by Fourier-transform infrared spectroscopy, X-ray diffraction, field-emission scanning electron microscopy, glossmetry, and electrochemical impedance analysis. The results revealed that the TMSPA-modified BaTiO3 surfaces considerably increased the dielectric property of the fabricated nanocomposite.


Assuntos
Compostos de Bário , Silanos , Cerâmica , Pós , Titânio
2.
Nanoscale ; 13(37): 15560-15568, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34596178

RESUMO

Here, we report an ultra-long-acting drug release nano-formulation based on porous silicon nanoparticles (pSiNPs) that are prepared by thermally induced silane dehydrocoupling and lipid-coating. This robust formulation offers the ability to release an anticancer drug, for up to 2 weeks, in various biological environments; pH 7.4 buffer, cancer cells, and tumor xenograft model.


Assuntos
Nanopartículas , Silício , Liberação Controlada de Fármacos , Porosidade , Silanos
3.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 56(1): 80-85, 2021 Jan 09.
Artigo em Chinês | MEDLINE | ID: mdl-34645240

RESUMO

Objective: To investigate the effects of different surface treatments protocol on the bonding strength between lithium disilicate glass ceramic and resin cements. Methods: Ceramic specimens of 15 mm×13 mm×3 mm were used to evaluate the effects of different surface treatments of hydrofluoric acid etching and silane coupling in current research. Firstly, the standard lithium ceramic specimens were divided into 8 groups (n=16), and were etched by 4.5% hydrofluoric acid for 0, 10, 20, 30, 40, 60, 120 and180 s. Then specimens in each group was further divided into two sub-groups. In one sub-group specimens were coated with coupling agents and in the other were not. Shear bonding strength (SBS) and failure mode were tested and analyzed. The surface morphologies of hydrofluoric acid-etched ceramic specimens were observed by the scanning electron microscopy (SEM). Secondly, after being etched by 4.5% hydrofluoric acid for 30 s, the lithium ceramic specimens were coated with coupling agents at different temperatures: room temperature (12 ℃) for 60 s, 60 ℃ hot air for 60 s and 100 ℃ hot air for 60 s (n=8). SBS and fracture mode were tested and analyzed. The infrared spectrum analysis was used to characterize the coupled surfaces of the ceramic samples. Results: The maximum SBS values were obtained after the specimens were etched for 30 s. The silane coupled group showed a higher SBS value [(25.91±4.30) MPa, P<0.05] than the no-silane-coupled group [(20.27±4.92) MPa]. SBS decreased with extended etching time (>30 s) and the SEM photos showed over-etching morphologies. The 60 ℃ hot air treatment resulted in the maximum SBS value [(28.70±5.32) MPa] than that of the room temperature [(20.08±3.64) MPa] or 100 ℃ hot air [(25.64±4.86) MPa, P<0.05]. And the cohesive failure mode was found in 60 ℃ hot air treatment group. The infrared spectroscopy analysis showed the highest amount of silicon oxide bond in the 60 ℃ hot air treatment group. Conclusions: In this study, for this product, the optimum etching time of 4.5% hydrofluoric acid was 30 s. Furthermore, an ideal SBS value could be obtained when the silane coupling agents were applied additionally. SBS could be increased substantially when the 30 s-etched-ceramic product was coated with silane coupling agents at 60 ℃ hot air for 60 s.


Assuntos
Colagem Dentária , Cimentos de Resina , Cerâmica , Porcelana Dentária , Ácido Fluorídrico , Teste de Materiais , Resistência ao Cisalhamento , Silanos , Propriedades de Superfície
4.
Molecules ; 26(19)2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34641270

RESUMO

The conjugation of biomolecules to magnetic nanoparticles has emerged as promising approach in biomedicine as the treatment of several diseases, such as cancer. In this study, conjugation of bioactive peptide fractions from germinated soybeans to magnetite nanoparticles was achieved. Different fractions of germinated soybean peptides (>10 kDa and 5-10 kDa) were for the first time conjugated to previously coated magnetite nanoparticles (with 3-aminopropyltriethoxysilane (APTES) and sodium citrate) by the Ugi four-component reaction. The crystallinity of the nanoparticles was corroborated by X-ray diffraction, while the particle size was determined by scanning transmission electron microscopy. The analyses were carried out using infrared and ultraviolet-visible spectroscopy, dynamic light scattering, and thermogravimetry, which confirmed the coating and functionalization of the magnetite nanoparticles and conjugation of different peptide fractions on their surfaces. The antioxidant activity of the conjugates was determined by the reducing power and hydroxyl radical scavenging activity. The nanoparticles synthesized represent promising materials, as they have found applications in bionanotechnology for enhanced treatment of diseases, such as cancer, due to a higher antioxidant capacity than that of fractions without conjugation. The highest antioxidant capacity was observed for a >10 kDa peptide fraction conjugated to the magnetite nanoparticles coated with APTES.


Assuntos
Antioxidantes/farmacologia , Nanopartículas de Magnetita/química , Peptídeos/farmacologia , Soja/química , Antioxidantes/química , Sequestradores de Radicais Livres/química , Germinação , Tamanho da Partícula , Peptídeos/química , Propilaminas/química , Silanos/química , Citrato de Sódio/química , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria , Difração de Raios X
5.
Molecules ; 26(19)2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34641509

RESUMO

A dual recognition system with a fluorescence quenching of quantum dots (QDs) and specific recognition of molecularly imprinted polymer (MIP) for the detection of chloramphenicol (CAP) was constructed. MIP@SiO2@QDs was prepared by reverse microemulsion method with 3-aminopropyltriethoxysilane (APTS), tetraethyl orthosilicate (TEOS) and QDs being used as the functional monomer, cross-linker and signal sources, respectively. MIP can specifically recognize CAP, and the fluorescence of QDs can be quenched by CAP due to the photo-induced electron transfer reaction between CAP and QDs. Thus, a method for the trace detection of CAP based on MIP@SiO2@QDs fluorescence quenching was established. The fluorescence quenching efficiency of MIP@SiO2@QDs displayed a desirable linear response to the concentration of CAP in the range of 1.00~4.00 × 102 µmol × L-1, and the limit of detection was 0.35 µmol × L-1 (3σ, n = 9). Importantly, MIP@SiO2@QDs presented good detection selectivity owing to specific recognition for CAP, and was successfully applied to quantify CAP in lake water with the recovery ranging 102.0~104.0%, suggesting this method has the promising potential for the on-site detection of CAP in environmental waters.


Assuntos
Cloranfenicol/análise , Fluorometria/métodos , Pontos Quânticos/química , Compostos de Cádmio/química , Fluorescência , Concentração de Íons de Hidrogênio , Lagos/análise , Limite de Detecção , Microscopia Eletrônica de Transmissão , Impressão Molecular , Propilaminas/química , Sensibilidade e Especificidade , Silanos/química , Dióxido de Silício/química , Espectroscopia de Infravermelho com Transformada de Fourier , Telúrio/química , Poluentes Químicos da Água/análise
6.
Biomacromolecules ; 22(11): 4582-4591, 2021 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-34613701

RESUMO

Accumulation of misfolded α-synuclein (α-syn) is a hallmark of Parkinson's disease (PD) thought to play important roles in the pathophysiology of the disease. Dendritic systems, able to modulate the folding of proteins, have emerged as promising new therapeutic strategies for PD treatment. Dendrimers have been shown to be effective at inhibiting α-syn aggregation in cell-free systems and in cell lines. Here, we set out to investigate the effects of dendrimers on endogenous α-syn accumulation in disease-relevant cell types from PD patients. For this purpose, we chose cationic carbosilane dendrimers of bow-tie topology based on their performance at inhibiting α-syn aggregation in vitro. Dopamine neurons were differentiated from induced pluripotent stem cell (iPSC) lines generated from PD patients carrying the LRRK2G2019S mutation, which reportedly display abnormal accumulation of α-syn, and from healthy individuals as controls. Treatment of PD dopamine neurons with non-cytotoxic concentrations of dendrimers was effective at preventing abnormal accumulation and aggregation of α-syn. Our results in a genuinely human experimental model of PD highlight the therapeutic potential of dendritic systems and open the way to developing safe and efficient therapies for delaying or even halting PD progression.


Assuntos
Dendrímeros , Doença de Parkinson , Dendrímeros/farmacologia , Neurônios Dopaminérgicos , Humanos , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/genética , Silanos , alfa-Sinucleína/genética
7.
J Adhes Dent ; 23(5): 429-435, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34549926

RESUMO

PURPOSE: Using the microshear bond strength (µSBS) test, this study investigated the bond strength between a hybrid ceramic and the extrinsic characterization layer after different ceramic surface treatments. MATERIALS AND METHODS: Hybrid ceramic blocks (Vita Enamic, Vita Zahnfabrik) were sectioned and randomly divided into 4 groups (N = 120) according to the surface treatment and aging (n = 15): P: polishing; E: acid etching with HF; A: aluminum oxide blasting; S: self-etching ceramic primer. The specimens were silanized, then cylinders of light-curing characterization material (Vita Enamic Stain, 1.6 mm diameter x 2 mm height) were fabricated, followed by glazing. The specimens were subsequently immersed in distilled water for 24 h and subjected to the µSBS test using a universal testing machine (load cell 0.5 mm/min, 50 kgf) or tested after thermocycling for 10,000 cycles in water (5°C-55°C). After treatment, the specimen surfaces were analyzed using SEM, with failure types defined as adhesive, predominantly adhesive, or cohesive. The data were analyzed by two-way ANOVA followed by Tukey's test (p < 0.05). RESULTS: The most frequent failure type was predominantly adhesive between ceramic and the characterization layer. There were statistically significant differences between the surface treatments (p < 0.05). Thermocycling did not lead to statistically signifcant different results (p > 0.05). For groups P and A, a sharp decrease in SBS was observed. CONCLUSION: The absence of surface treatment drastically reduced the microshear bond strength between the ceramic and the characterization layer. Conditioning with 5% hydrofluoric acid for 60 s is the most suitable treatment for adhesion of the characterization layer to hybrid ceramic.


Assuntos
Colagem Dentária , Cimentos de Resina , Condicionamento Ácido do Dente , Cerâmica , Porcelana Dentária , Teste de Materiais , Silanos , Propriedades de Superfície , Resistência à Tração
8.
J Phys Chem B ; 125(39): 11078-11090, 2021 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-34570497

RESUMO

In the context of the COVID-19 outbreak since December 2019, antigenic tests are widely used, for diagnosis purposes, to detect the SARS-CoV-2 spike protein in nasopharyngeal fluid through its interactions with specific antibodies. However, the SARS-CoV-2 spike protein is subject to rapid mutations yielding more and more variants that might lose their affinity toward the currently used antibodies. The virus entry into the host cell involves interactions between the angiotensin-converting enzyme 2 (ACE2) and the SARS-CoV-2 spike protein receptor-binding domain. Consequently, ACE2 could be a target with limited mutation escaping possibilities. However, as the enzyme has not evolved to recognize the virus, its affinity with the spike protein receptor-binding domain is lower than that with specific antibodies. The present molecular dynamics simulations study suggests that the adsorption of the ACE2 on specific silane monolayers could increase its affinity toward the spike protein receptor-binding domain. Indeed, silane monolayers, combining silane molecules with short alkyl chains and positively charged head groups and silane molecules without charged head groups, could adsorb the ACE2 while maintaining its bioactivity (orientation compatible with the spike protein trapping, low conformational changes) and increasing its interactions with the spike protein receptor-binding domain (number of hydrogen bonds and electrostatic interactions) to lead to an increase by 20% both in the binding free energy and in the enzyme /receptor-binding domain rupture force. This work could help develop biosensing tools efficient toward any variants of the SARS-CoV-2 spike protein.


Assuntos
COVID-19 , Glicoproteína da Espícula de Coronavírus , Enzima de Conversão de Angiotensina 2 , Humanos , Simulação de Dinâmica Molecular , SARS-CoV-2 , Silanos , Glicoproteína da Espícula de Coronavírus/genética
9.
Int J Mol Sci ; 22(17)2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34502104

RESUMO

In this work, a multi-analytical approach involving nitrogen porosimetry, small angle neutron and X-ray scattering, Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies, X-ray diffraction, thermal analysis and electron microscopy was applied to organically modified silica-based xerogels obtained through the sol-gel process. Starting from a tetraethoxysilane (TEOS) precursor, methyltriethoxysilane (MTES) was added to the reaction mixture at two different pH values (2.0 and 4.5) producing hybrid xerogels with different TEOS/MTES molar ratios. Significant differences in the structure were revealed in terms of the chemical composition of the silica network, hydrophilic/hydrophobic profile, particle dimension, pore shape/size and surface characteristics. The combined use of structural characterization methods allowed us to reveal a relation between the cavity dimensions, the synthesis pH value and the grade of methyl substitution. The effect of the structural properties on the controlled Captopril release efficiency has also been tested. This knowledge facilitates tailoring the pore network for specific usage in biological/medical applications. Knowledge on structural aspects, as reported in this work, represents a key starting point for the production of high-performance silica-based hybrid materials showing enhanced efficacy compared to bare silica prepared using only TEOS.


Assuntos
Liberação Controlada de Fármacos , Nanocápsulas/química , Sílica Gel/síntese química , Captopril/administração & dosagem , Captopril/química , Microscopia Eletrônica , Difração de Nêutrons , Espalhamento a Baixo Ângulo , Silanos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
10.
J Org Chem ; 86(18): 13160-13168, 2021 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-34478290

RESUMO

An efficient route for the synthesis of 1-aryl-2,2-difluoroalkenes via 1,2-desilylative defluorination is disclosed. Only a catalytic amount of fluoride source is required to initiate the desilylation and afford gem-difluoroalkenes in very good to quantitative yields, using mild reaction conditions in dimethyl carbonate as a green solvent. This reaction uses (1-aryl)-2,2,2-trifluoroethyl-silanes, which are easily prepared via the insertion reaction of trifluoroethyl diazo alkanes into the Si-H bond of tertiary organosilanes. (1-Aryl)-perfluoroalkyl-silanes cleanly afford the corresponding (Z)-1-benzylideneperfluoroalkanes, which upon hydrodefluorination furnish the (E)-ß(perfluoroalkyl)styrene derivatives with excellent yield and complete stereoselectivity. A one-pot system involving sequential insertion and desilylative-defluorination is also suitable for this transformation. This method demonstrates the usefulness of organosilanes toward the preparation of fluorinated alkenes as synthetically useful targets.


Assuntos
Compostos de Organossilício , Silanos , Alcenos , Catálise , Fluoretos
11.
Colloids Surf B Biointerfaces ; 208: 112085, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34478956

RESUMO

Fe3O4 nanoparticle loaded with silver ion was prepared as a more efficient, safer, and less environmentally hazardous silver-based antibacterial nanomaterial. The Fe3O4 nanoparticle was modified using 3-aminopropyl trimethoxysilane (APTMS) to enhance the silver ion adsorption capacity and antibacterial activity. Silver ions were adsorbed on pristine Fe3O4 and Fe3O4@NH2 to enhance antibacterial activity. Energy dispersive spectroscopy (EDS) results showed that Fe3O4 adsorbed 2.74 wt% of Ag, whereas Fe3O4@NH2 adsorbed 9.88 wt%. Pristine Fe3O4NP, silver ion loaded Fe3O4 (Fe3O4-Ag), and silver ion loaded Fe3O4@NH2 (Fe3O4@NH2-Ag) were used to manufacture carrageenan-based composite films. Compared with Fe3O4-Ag, Fe3O4@NH2-Ag exhibited stronger antimicrobial activity against E. coli (8.82 vs. 5.02 log reduction) and L. monocytogenes (10.09 vs. 3.93 log reduction). While the addition of Fe3O4 significantly reduced the WCA of the carrageenan films from 61.1 ± 5.4 ° to 37.2 ± 2.1 °, the additions of Fe3O4-Ag and Fe3O4@NH2-Ag reduced the WCA of the film to a lesser extent (56.9 ± 4.6 ° and 56.9 ± 4.6 °, respectively). Fe3O4NP also improved the thermal stability of carrageenan over Fe3O4@NH2-Ag (22 °C vs. 13 °C) and UV blocking properties (T280, 0.1 ± 0.0 % vs. 3.3 ± 1.5 %).


Assuntos
Nanopartículas Metálicas , Nanocompostos , Nanopartículas , Antibacterianos/farmacologia , Carragenina , Escherichia coli , Íons , Silanos , Prata/farmacologia
12.
Int J Mol Sci ; 22(16)2021 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-34445073

RESUMO

Human immunodeficiency virus (HIV-1) is still a major problem, not only in developing countries but is also re-emerging in several developed countries, thus the development of new compounds able to inhibit the virus, either for prophylaxis or treatment, is still needed. Nanotechnology has provided the science community with several new tools for biomedical applications. G2-S16 is a polyanionic carbosilane dendrimer capable of inhibiting HIV-1 in vitro and in vivo by interacting directly with viral particles. One of the main barriers for HIV-1 eradication is the reservoirs created in primoinfection. These reservoirs, mainly in T cells, are untargetable by actual drugs or immune system. Thus, one approach is inhibiting HIV-1 from reaching these reservoir cells. In this context, macrophages play a main role as they can deliver viral particles to T cells establishing reservoirs. We showed that G2-S16 dendrimer is capable of inhibiting the infection from infected macrophages to healthy T CD4/CD8 lymphocytes by eliminating HIV-1 infectivity inside macrophages, so they are not able to carry infectious particles to other body locations, thus preventing the reservoirs from forming.


Assuntos
Alcanossulfonatos/farmacologia , Fármacos Anti-HIV/farmacologia , Dendrímeros/farmacologia , Infecções por HIV/tratamento farmacológico , HIV-1/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Compostos de Organossilício/farmacologia , Silanos/farmacologia , Linhagem Celular , Células Cultivadas , Infecções por HIV/transmissão , Humanos , Macrófagos/virologia , Polieletrólitos/farmacologia
13.
Molecules ; 26(16)2021 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-34443351

RESUMO

For this study, we tested and optimized silicon surface functionalization procedures for capturing urinary extracellular vesicles (uEVs). The influence of the silane type (APTES or GOPS) and protein concentration on the efficiency of uEVs binding was investigated. Human lactadherin protein (LACT) was used to capture uEVs. We applied surface characterization techniques, including ellipsometry, atomic force microscopy, and time-of-flight secondary ion mass spectrometry, to observe changes in the biosensor surface after each functionalization step. uEVs were purified by a low-vacuum filtration method and concentrated by ultracentrifugation. The physical parameters of uEVs after the isolation procedure, such as morphology and size distribution, were determined using transmission electron microscopy and tunable resistive pulse sensing methods. We observed a gradual growth of the molecular layer after subsequent stages of modification of the silicon surface. The ToF-SIMS results showed no changes in the mean intensities for the characteristic peaks of amino acids and lipids in positive and negative polarization, in terms of the surface-modifying silane (APTES or GOPS) used. The most optimal concentration of LACT for the tested system was 25 µg/mL.


Assuntos
Técnicas Biossensoriais/métodos , Desenho de Fármacos , Vesículas Extracelulares/metabolismo , Humanos , Silanos/química , Silício/química , Propriedades de Superfície
14.
Dent Mater J ; 40(5): 1264-1269, 2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34193726

RESUMO

The purpose of this study was to investigate the effects of fiber orientation, silane treatment, and thermal cycling on the retention force of fiber-reinforced composite resin (FRC) posts on resin composite. Two types of FRC posts (linear and woven) were prepared with and without silane treatment. Pull-out test specimens were made of FRC posts and resin composite for core buildup. Specimens were either incubated in distilled water for 24 h or subjected to 10,000 thermal cycles. The maximum fracture load obtained by a pull-out test was defined as the retention force. Fracture modes were observed after the test. Fiber orientation and thermal cycling did not affect the retention force on resin composite, and the retention force was improved by silane treatment. Whereas, fiber orientation affected the fracture mode. The result showed woven fiber orientation could contribute to the mechanically interlocking with the resin composite.


Assuntos
Colagem Dentária , Técnica para Retentor Intrarradicular , Resinas Compostas , Análise do Estresse Dentário , Vidro , Teste de Materiais , Cimentos de Resina , Silanos
15.
Chemistry ; 27(47): 12011, 2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34228370

RESUMO

Invited for the cover of this issue is the group of Thomas Müller at the University of Oldenburg. The image shows the calculated spin distribution of a persistent silacyclopentadienyl radical. Read the full text of the article at 10.1002/chem.202101415.


Assuntos
Ânions , Humanos , Silanos
16.
Int J Biol Macromol ; 185: 997-1004, 2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34237368

RESUMO

Two-faced characteristics and performance of materials driven by asymmetric physical or chemical properties exist in Janus hybrid materials which show synergistic and improved properties for a variety of applications. Here, we report a facile synthesis of Janus hybrid sustainable cellulose nanofibers (CNFs) sponge with asymmetric wettability and strong mechanical property for excellent separation efficiency of oil-water emulsions. Briefly, the CNF Janus hybrid sponge was fabricated by freeze-drying of two separate CNF suspensions into one, each prepared separately by introducing CNFs in methyltrimethoxysilane (MTMS) or 3-glycidoxypropyltrimethoxysilane (GPTMS) for hydrophobic or hydrophilic performance, respectively. The sponge demonstrated satisfactory mechanical stability with an excellent recovery from 80% compressive strain and high pore tortuosity. When employed for oil-water separation, the Janus hybrid sponge could selectively be used to collect water or oil by just switching its side facing the oil-water mixture feed via unidirectional gravity-assisted separation, with recyclability. The fabrication of such Janus hybrid sponge is one of the many approaches for utilizing nanofibers in structurally adaptive, self-supported asymmetric membrane structures in a 3D network.


Assuntos
Celulose/química , Óleos/química , Água/química , Emulsões , Liofilização , Interações Hidrofóbicas e Hidrofílicas , Nanofibras , Porosidade , Silanos/química , Molhabilidade
17.
Biosensors (Basel) ; 11(7)2021 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-34209744

RESUMO

Bioelectrodes mediated by metal oxide nanoparticles have facilitated the development of new sensors in medical diagnosis. High-purity TiO2 nanoparticles (NPs) were synthesized through thermal plasma and deposited directly on an interdigitated electrode. The surface of the TiO2-deposited electrode was activated with (3-aminopropyl) triethoxysilane (APTES) followed by fixing the single-stranded probe deoxyribonucleic acid (DNA) to fabricate the DNA biosensor. The structural properties of the deposited TiO2 nanoparticles were analyzed using a transmission electron microscope (TEM), X-ray diffraction (XRD), and a dynamic light scattering (DLS) system. The chemical composition and structural properties of the TiO2 nanoparticle layer and the fixed layer were analyzed by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). E. coli O157:H7, a well-known pernicious pathogenic bacterial species, was detected as a target DNA of the prepared DNA biosensor, and the characteristics of DNA detection were determined by the current change using a picoammeter. The degree of binding between the probe DNA and the target DNA was converted into an electrical signal using the picoammeter method to quantitatively analyze the concentration of the target DNA. With the specificity experiment, it was confirmed that the biosensor was able to discriminate between nucleotides with mismatched, non-complementary, or complementary sequences.


Assuntos
Técnicas Biossensoriais , DNA/análise , Técnicas Eletroquímicas , Eletrodos , Escherichia coli O157 , Nanopartículas Metálicas/química , Nanopartículas/química , Propilaminas , Silanos , Titânio/química , Difração de Raios X
18.
ACS Appl Mater Interfaces ; 13(29): 34877-34888, 2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34254781

RESUMO

This paper demonstrates the feasibility of a long-range antenna sensor embedded underneath a liquid repellent fabric to be employed as a wearable sensor in personal protective fabrics. The sensor detects and monitors hazardous aqueous liquids on the outer layer of fabrics, to add an additional layer of safety for professionals working in hazardous environments. A modified patch antenna was designed to include a meandering-shaped resonant structure, which was embedded underneath the fabric. Superhydrophobic fabrics were prepared using silica nanoparticles and a low-surface-energy fluorosilane. 4 to 20 µL droplets representing hazardous aqueous solutions were drop-cast on the fabrics to investigate the performance of the embedded antenna sensor. Long-range (S21) measurements at a distance of 2-3 m were performed using the antenna sensor with treated and untreated fabrics. The antenna sensor successfully detected the liquid for both types of fabrics. The resonant frequency sensitivity of the antenna sensor underneath the treated fabric exhibiting superhydrophobicity was measured as 370 kHz/µL, and 1 MHz/µL for the untreated fabric. The results demonstrate that the antenna sensor is a good candidate for wearable hazardous aqueous droplet detection on fabrics.


Assuntos
Equipamento de Proteção Individual , Têxteis , Água/análise , Dispositivos Eletrônicos Vestíveis , Interações Hidrofóbicas e Hidrofílicas , Nanopartículas/química , Silanos/química , Dióxido de Silício/química , Molhabilidade , Tecnologia sem Fio
19.
J Adhes Dent ; 23(4): 335-345, 2021 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-34269544

RESUMO

PURPOSE: The pretreatment of glass-ceramic before adhesive cementation can be performed with hydrofluoric acid (HF)/silanization (S) or with an ammonium polyfluoride-containing primer (APF). It can be modified by application of a silane-containing universal adhesive (UA) and/or additional silanization. The aim of this study was to evaluate the bond strength of composite cements to two different glass ceramics after different pretreatments and aging. MATERIALS AND METHODS: Disks of leucite-reinforced glass-ceramic or lithium-disilicate glass-ceramic were pretreated with HF+S, HF+UA, HF+S+UA, APF, or APF+S, bonded in pairs with composite cement and sectioned into microsticks (n = 96/group). The microtensile bond strength was determined either after 24 h (n = 48) or after aging for 6 months in water (n = 48). Fracture patterns were analyzed at 50X magnification. Statistical evaluation was performed using the Kruskal-Wallis test, pairwise comparisons with Bonferroni's correction, and the chi-squared test (p < 0.05). RESULTS: Pretreatment with HF+UA or APF led to significantly lower bond strength compared to HF+S. Additional silanization after application of UA or APF resulted in a significant increase in bond strength. After aging, HF+UA groups showed significantly lower bond strengths, independent of additive silanization. Aging did not affect APF-pretreated leucite-reinforced glass-ceramic; for lithium-disilicate glass-ceramic, the bond strength dropped significantly. Additional silanization improved aging resistance for the respective groups. CONCLUSION: Bond strength and its long-term stability depend on the ceramic used and on the pretreatment. An ammonium polyfluoride-containing primer seems to be a promising option compared to conventional pretreatment with hydrofluoric acid. Additive silanization improves the long-term stability of the microtensile bond strength.


Assuntos
Colagem Dentária , Cimentos de Resina , Condicionamento Ácido do Dente , Cerâmica , Porcelana Dentária , Ácido Fluorídrico , Teste de Materiais , Silanos , Silicatos , Propriedades de Superfície , Resistência à Tração
20.
Int J Mol Sci ; 22(13)2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34281151

RESUMO

The application of siRNA in gene therapy is mainly limited because of the problems with its transport into cells. Utilization of cationic dendrimers as siRNA carriers seems to be a promising solution in overcoming these issues, due to their positive charge and ability to penetrate cell membranes. The following two types of carbosilane dendrimers were examined: CBD-1 and CBD-2. Dendrimers were complexed with pro-apoptotic siRNA (Mcl-1 and Bcl-2) and the complexes were characterized by measuring their zeta potential, circular dichroism and fluorescence of ethidium bromide associated with dendrimers. CBD-2/siRNA complexes were also examined by agarose gel electrophoresis. Both dendrimers form complexes with siRNA. Moreover, the cellular uptake and influence on the cell viability of the dendrimers and dendriplexes were evaluated using microscopic methods and XTT assay on MCF-7 cells. Microscopy showed that both dendrimers can transport siRNA into cells; however, a cytotoxicity assay showed differences in the toxicity of these dendrimers.


Assuntos
RNA Interferente Pequeno/uso terapêutico , Silanos/farmacologia , Cátions , Sobrevivência Celular , Dicroísmo Circular , Dendrímeros/química , Dendrímeros/farmacologia , Terapia Genética/métodos , Humanos , Células MCF-7 , Proteína de Sequência 1 de Leucemia de Células Mieloides/genética , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Tamanho da Partícula , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , RNA de Cadeia Dupla/genética , RNA Interferente Pequeno/genética , Silanos/química , Silanos/metabolismo
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