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1.
Nat Commun ; 12(1): 2407, 2021 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-33893308

RESUMO

Many features of extracellular matrices, e.g., self-healing, adhesiveness, viscoelasticity, and conductivity, are associated with the intricate networks composed of many different covalent and non-covalent chemical bonds. Whereas a reductionism approach would have the limitation to fully recapitulate various biological properties with simple chemical structures, mimicking such sophisticated networks by incorporating many different functional groups in a macromolecular system is synthetically challenging. Herein, we propose a strategy of convergent synthesis of complex polymer networks to produce biomimetic electroconductive liquid metal hydrogels. Four precursors could be individually synthesized in one to two reaction steps and characterized, then assembled to form hydrogel adhesives. The convergent synthesis allows us to combine materials of different natures to generate matrices with high adhesive strength, enhanced electroconductivity, good cytocompatibility in vitro and high biocompatibility in vivo. The reversible networks exhibit self-healing and shear-thinning properties, thus allowing for 3D printing and minimally invasive injection for in vivo experiments.


Assuntos
Adesivos/química , Condutividade Elétrica , Hidrogéis/química , Metais/química , Adesivos/síntese química , Adesivos/farmacologia , Animais , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Bacillus subtilis/efeitos dos fármacos , Materiais Biocompatíveis/síntese química , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Hidrogéis/síntese química , Hidrogéis/farmacologia , Camundongos , Microscopia Eletrônica , Mioblastos/citologia , Mioblastos/efeitos dos fármacos , Polímeros/síntese química , Polímeros/química , Polímeros/farmacologia
2.
Carbohydr Polym ; 261: 117878, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33766365

RESUMO

Hydrogels have gained great attentions as wound dressing. Binding to the tissue and preventing wound infection were the basic requirements for an "ideal dressing". We employed l-DOPA and ε-Poly-l-lysine to modify thermo-sensitive hydroxybutyl chitosan (HBC) to obtain (l-DOPA) - (ε-Poly-l-lysine)-HBC hydrogels (eLHBC). The eLHBC exhibited an almost 1.5 fold (P < 0.01) increase in wet adhesion strength compared to HBC. Upon the introduction of ε-Poly-l-lysine, eLHBC presented inherent antimicrobial property and prevented wound infection and inflammation response. Bone marrow mesenchymal stem cells (BMSCs) encapsulated in the eLHBC (BMSCs ⊂ eLHBC) could secret cytokins and growth factors via paracrine and promote the migration of fibroblast cells. BMSCs ⊂ eLHBC enhanced the complete skin-thickness wound healing via promoting collagen deposition and inhibiting infection and inflammation in vivo with wound closure rate being above 99 % after 15 days. The bioinspired, tissue-adhesive eLHBC could serve as advanced wound dressings for facilitating tissue repair and regeneration.


Assuntos
Adesivos , Curativos Hidrocoloides , Quitosana/análogos & derivados , Células-Tronco Mesenquimais/efeitos dos fármacos , Tecidos Suporte/química , Adesivos/síntese química , Adesivos/química , Adesivos/farmacologia , Animais , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Bioengenharia/métodos , Materiais Biomiméticos/síntese química , Materiais Biomiméticos/química , Materiais Biomiméticos/farmacologia , Bivalves/química , Bivalves/metabolismo , Adesão Celular/efeitos dos fármacos , Técnicas de Cultura de Células/instrumentação , Técnicas de Cultura de Células/métodos , Células Cultivadas , Quitosana/síntese química , Quitosana/química , Quitosana/farmacologia , Matriz Extracelular/química , Matriz Extracelular/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Hidrogéis/síntese química , Hidrogéis/química , Hidrogéis/farmacologia , Masculino , Teste de Materiais , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/fisiologia , Camundongos , Testes de Sensibilidade Microbiana , Peptídeos/síntese química , Peptídeos/química , Peptídeos/farmacologia , Coelhos , Ratos , Ratos Sprague-Dawley , Temperatura , Cicatrização/efeitos dos fármacos
3.
Life Sci ; 270: 119126, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33508295

RESUMO

AIMS: To investigate the biomimetic fabrication of fibrous-like organic-inorganic hybrid structures via a simple bottom-up approach, viz. self-assembly of simple molecules, and apply fibrous-like composites as a novel primer to improve dentin bond strengths of self-etch adhesives. MATERIALS AND METHODS: The resultants of commercial amorphous calcium phosphate (ACP) nanoparticles and 10-methacryloyloxydecyl dihydrogen phosphate (MDP) ethanol-aqueous solution were analyzed by TEM, SEM, XRD, DLS and AFM. The acid and alkali resistance of abovementioned self-assembled composites were analyzed with TEM. Micro-tensile bond strengths (MTBS) tests were performed after polished dentin surfaces were pretreated with self-assembled composites. The pretreated dentin surfaces and dentin-resin interfaces were characterized by SEM/TEM. KEY FINDINGS: ACP nanoparticles in MDP solution could self-assemble into fibrous-like nanotube structures in 8 nm diameter. Self-assembly and self-proliferation process went from ACP nanoparticles, dissolved ACP nanoparticles (less than 50 nm), twig-like structures and fibrous-like nanotubes to cellular networks. The fibrous-like nanotubes were only detected when the amount of ACP in reaction system were more than 0.01 g. The more ACP interacted with MDP, the more fibrous-like nanotubes were formed. After the dentin surfaces were treated with fibrous-like nanotube composites, MTBS could be significantly improved. Moreover, the fibrous-like nanotube structures could be resistant to acidic challenge, and were stable at least for 3 months. SIGNIFICANCE: The fibrous-like nanotube structures could be self-assembled via a bottom-up approach at certain ratio of MDP and commercial ACP nanoparticles. The application of fibrous-like nanotube composites as a novel primer prior to self-etch adhesives greatly improved dentin bond strengths.


Assuntos
Biomimética/métodos , Dentina/química , Nanotubos/química , Adesivos/química , Fosfatos de Cálcio/química , Humanos , Teste de Materiais/métodos , Metacrilatos/química , Nanopartículas/química , Resistência à Tração/fisiologia
4.
Int J Mol Sci ; 22(2)2021 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-33445775

RESUMO

Accelerating wound healing with minimized bacterial infection has become a topic of interest in the development of the new generation of tissue bio-adhesives. In this study, we fabricated a hydrogel system (MGC-g-CD-ic-TCS) consisting of triclosan (TCS)-complexed beta-cyclodextrin (ß-CD)-conjugated methacrylated glycol chitosan (MGC) as an antibacterial tissue adhesive. Proton nuclear magnetic resonance (1H NMR) and differential scanning calorimetry (DSC) results showed the inclusion complex formation between MGC-g-CD and TCS. The increase of storage modulus (G') of MGC-g-CD-ic-TCS after visible light irradiation for 200 s indicated its hydrogelation. The swollen hydrogel in aqueous solution resulted in two release behaviors of an initial burst and sustained release. Importantly, in vitro and in vivo results indicated that MGC-g-CD-ic-TCS inhibited bacterial infection and improved wound healing, suggesting its high potential application as an antibacterial tissue bio-adhesive.


Assuntos
Adesivos/química , Quitosana/química , Glicóis/química , Hidrogéis/química , Triclosan/química , beta-Ciclodextrinas/química , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Luz , Masculino , Camundongos , Ratos , Ratos Sprague-Dawley , Cicatrização/efeitos dos fármacos
5.
J Mater Chem B ; 9(3): 783-792, 2021 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-33333547

RESUMO

Pesticides play a very important role in pest control and plant protection. However, they can be limited by a tendency to cause ecological system damage due to significant losses into the environment. To increase pesticide utilization efficiency, we developed highly leaf-adhesive avermectin nanocapsules (Av-pH-cat@CS) with pH-responsive controlled release properties. The Av-pH-cat@CS nanocapsules displayed good thermal stability and photostability in response to UV light irradiation. The Av-pH-cat@CS nanocapsules could be disrupted at low pH and they exhibited excellent controlled release in response to pH, which improved the release of avermectins. In addition, the Av-pH-cat@CS nanocapsules were highly adhesive to crop leaves as a result of strong hydrogen bonding, which prolonged the retention time on crop leaves. The Av-pH-cat@CS nanocapsules with pH-responsive release and strong leaf adhesion improved the control efficacy and enhanced the utilization efficiency. Our findings offer a promising approach to prolonging pesticide duration on crop leaves and improving the utilization efficiency.


Assuntos
Adesivos/química , Antiprotozoários/química , Ivermectina/análogos & derivados , Nanocápsulas/química , Praguicidas/química , Adesivos/síntese química , Antiprotozoários/síntese química , Liberação Controlada de Fármacos , Ligação de Hidrogênio , Concentração de Íons de Hidrogênio , Ivermectina/síntese química , Ivermectina/química , Estrutura Molecular , Tamanho da Partícula , Praguicidas/síntese química , Folhas de Planta/química , Propriedades de Superfície , Fatores de Tempo , Zea mays/química
6.
Carbohydr Polym ; 254: 117298, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33357866

RESUMO

As a flexible material, hydrogels have attracted considerable attention in the exploration of various wearable sensor devices. However, the performance of the existing hydrogels is often too single, which limits its further application. Here, a conductive hydrogel with adhesiveness, toughness, self-healing and anti-swelling properties was successfully prepared by adding 2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) to the polyacrylic acid/ferric ionic (PAA/Fe3+) cross-linking system. Based on the existence of three types of non-covalent interactions in the hydrogel system, including electrostatic interaction, coordination interaction and hydrogen bonds, the hydrogel possessed excellent mechanical properties (tensile stress and strain were 827 kPa and 1652 %, respectively), self-healing properties (self-healing efficiency reached 83.3 % at room temperature) and anti-swelling properties. In addition, the introduction of HACC also successfully gave the hydrogel outstanding adhesiveness. Moreover, the existence of iron ions provided sensitive conductivity to the hydrogel, which could be used as a flexible sensor for directly monitoring various motions. Therefore, this simple strategy for preparation of multifunctional hydrogels would expand the application of a new generation of hydrogel-based sensors.


Assuntos
Adesivos/química , Quitosana/análogos & derivados , Hidrogéis/química , Compostos de Amônio Quaternário/química , Dispositivos Eletrônicos Vestíveis , Resinas Acrílicas/química , Adesividade , Quitosana/química , Reagentes para Ligações Cruzadas/química , Condutividade Elétrica , Ligação de Hidrogênio , Íons/química , Ferro/química , Eletricidade Estática , Resistência à Tração
7.
Carbohydr Polym ; 254: 117316, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33357879

RESUMO

For conductive hydrogels applied in biosensors, wearable devices and so forth, multifunctionality is an inevitable trend of development to meet various practical requirements and enhance human experience. Herein, inspired by nanocomposite, double-network (DN) and mussel chemistry, a new Graphene oxide@Dopamine/Alginate/Poly(acrylic acid-co-acrylamide) [GO@DA/Alginate/P(AAc-co-AAm)] hydrogel was fabricated through one-pot in-situ radical copolymerization. GO@DA nanofillers, prepared via GO confined DA polymerization, imparted the hydrogel with remarkable adhesiveness. Alginate/P(AAc-co-AAm) DN matrix, physically and chemically crosslinked by Fe3+ and N,N'-Methylenebisacrylamide, made hydrogels ultrastretchable, self-healing and biocompatible. With contents of DA and alginate accurately regulated, the tensile strength, elongation, adhesion strength and conductivity of the optimal hydrogel could reach 320.2 kPa, 1198 %, 36.9 kPa and 3.24 ± 0.12 S/m, respectively. What's more notable was that the synergistic integration of repeatable adhesiveness, strain sensitivity, use stability, self-healing ability and biocompatibility provided such hydrogels with tremendous possibility of practical application for strain sensors.


Assuntos
Acrilamidas/química , Adesivos/química , Alginatos/química , Bivalves/química , Dopamina/química , Grafite/química , Hidrogéis/química , Nanogéis/química , Adesividade , Animais , Materiais Biocompatíveis/química , Técnicas Biossensoriais , Sobrevivência Celular/efeitos dos fármacos , Condutividade Elétrica , Humanos , Camundongos , Células NIH 3T3 , Testes do Emplastro , Polimerização , Resistência à Tração
8.
Carbohydr Polym ; 254: 117403, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33357891

RESUMO

This work is focused on the modification of the interphase zone in short flax fibres / polypropylene (PP) composites by a bio-inspired modification of fibres called "nanostructuration" that uses the adsorption of biomass by-products, i.e. cellulose nanocrystals (CNC) and xyloglucan (XG), to create hierarchical flax fibres. The wettability and interfacial adhesion study reveals a strong decrease in the polar character of CNC modified flax fibres, hence increasing the work of adhesion with PP. Moreover, combining XG/CNC modified interphases with MAPP coupling agent enhances the ultimate mechanical properties of biocomposites with higher tensile strength and work of rupture, and modifies failure mechanisms as revealed by in situ micro-mechanical tensile SEM experiments. Bio-based hierarchical composites inspired by naturally occurring nanostructures open a new path for the development of sustainable composites with enhanced structural properties.


Assuntos
Celulose/química , Linho/química , Glucanos/química , Temperatura Alta , Nanocompostos/química , Nanopartículas/química , Polipropilenos/química , Xilanos/química , Adesivos/química , Adsorção , Resistência à Tração , Água/química , Molhabilidade
9.
Carbohydr Polym ; 251: 117019, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33142580

RESUMO

The advent of high-performance conductive organohydrogels, which are sustainable in extremely cold environment, has attracted immersing interest in biosensors. In this work, a highly stretchable, self-healable, adhesive and antibacterial cellulose-based ionic conductive organohydrogel with low-temperature strain sensitivity was developed, using in-situ polymerization of acrylamide in glycerol-water with poly (vinyl alcohol), chitosan, FeCl3 and 2,2,6,6-Tetramethylpiperidine-1-oxyl oxidized cellulose nanofibril (TCNF). Owing to their chemically cross-linked structures and multiple H-bonding networks, the organohydrogel exhibits excellent mechanical properties, such as high stretchability (540 %), high compression strength (0.44 MPa), nearly 87 % self-healing efficiency and adhesive to various substrates. Also, good antibacterial property was confirmed by the diameter of inhibition zone (∼5.1 mm) against Salmonella enteritidis. Notably, the organohydrogels remained high conductivity and flexibility even below -20 °C, which can be applied as low-temperature strain sensor for real-time. Therefore, it has promising applications in artificial intelligence and personal healthcare under cold environment.


Assuntos
Acrilamida/química , Antibacterianos/química , Técnicas Biossensoriais , Celulose/química , Quitosana/química , Hidrogéis , Adesivos/química , Antibacterianos/farmacologia , Temperatura Baixa , Condutividade Elétrica , Hidrogéis/síntese química , Hidrogéis/química , Fenômenos Mecânicos , Salmonella enteritidis/efeitos dos fármacos
10.
Carbohydr Polym ; 254: 117478, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33357930

RESUMO

Waterborne polyurethanes (WBPUs) have been proposed as ecofriendly elastomers with several applications in coatings and adhesives. WBPU's physicochemical properties can be enhanced by the addition of cellulose nanocrystals (CNCs). The way CNCs are isolated has a strong effect on their properties and can determine their role as reinforcement. In this work, CNCs produced using ancestral endoglucanase (EnCNCs) were used as reinforcement for WBPU and compared with CNC produced by sulfuric acid hydrolysis (AcCNC). The enzymatic method produced highly thermostable and crystalline CNCs. The addition of small contents of EnCNCs improved the thermomechanical stability and mechanical properties of WBPUs, even better than commercial AcCNCs. Besides, WBPU reinforced by adding EnCNCs was studied as a coating for paper materials, increasing its abrasion resistance and as electrospun nanocomposite mats where EnCNCs helped maintaining the morphology of the fibers.


Assuntos
Celulase/química , Celulose/química , Química Verde , Nanopartículas/química , Poliuretanos/química , Adesivos/química , Celulase/genética , Celulase/metabolismo , Materiais de Construção/análise , Humanos , Hidrólise , Nanocompostos/química , Nanocompostos/ultraestrutura , Nanopartículas/ultraestrutura , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Ácidos Sulfúricos/química , Água/química
11.
Methods Mol Biol ; 2174: 277-297, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32813257

RESUMO

Stiffness control of cell culture platforms provides researchers in cell biology with the ability to study different experimental models in conditions of mimicking physiological or pathological microenvironments. Nevertheless, the signal transduction pathways and drug sensibility of cancer cells have been poorly characterized widely using biomimetic platforms because the limited experience of cancer cell biology groups about handling substrates with specific mechanical properties. The protein cross-linking and stiffening control are crucial checkpoints that could strongly affect cell adhesion and spreading, misrepresenting the data acquired, and also generating inaccurate cellular models. Here, we introduce a simple method to adhere to polyacrylamide (PAA) hydrogels on glass coverslips without any special treatment for mechanics studies in cancer cell biology. By using a commercial photosensitive glue, Loctite 3525, it is possible to polymerize PAA hydrogels directly on glass surfaces. Furthermore, we describe a cross-linking reaction method to attach proteins to PAA as an alternative method to Sulfo-SANPAH cross-linking, which is sometimes difficult to implement and reproduce. In this chapter, we describe a reliable procedure to fabricate ECM protein-cross-linked PAA hydrogels for mechanotransduction studies on cancer cells.


Assuntos
Resinas Acrílicas/química , Hidrogéis/química , Neoplasias/patologia , Adesivos/química , Reagentes para Ligações Cruzadas/química , Matriz Extracelular/metabolismo , Matriz Extracelular/patologia , Proteínas da Matriz Extracelular/química , Imunofluorescência , Vidro , Células Hep G2 , Humanos , Mecanotransdução Celular , Metacrilatos/química , Microambiente Tumoral
12.
Methods Mol Biol ; 2211: 183-191, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33336278

RESUMO

The simple and versatile CRISPR/Cas9 system is a promising strategy for genome editing in mammalian cells. Generally, the genome editing components, namely Cas9 protein and single-guide RNA (sgRNA), are delivered in the format of plasmids, mRNA, or ribonucleoprotein (RNP) complexes. In particular, non-viral approaches are desirable as they overcome the safety concerns posed by viral vectors. To control cell fate for tissue regeneration, scaffold-based delivery of genome editing components will offer a route for local delivery and provide possible synergistic effects with other factors such as topographical cues that are co-delivered by the same scaffold. In this chapter, we detail a simple method of surface modification to functionalize electrospun nanofibers with CRISPR/Cas9 RNP complexes. The mussel-inspired bio-adhesive coating will be used as it is a simple and effective method to immobilize biomolecules on the surface. Nanofibers will provide a biomimicking microenvironment and topographical cues to seeded cells. For evaluation, a model cell line with single copies of enhanced green fluorescent protein (U2OS.EGFP) will be used to validate the efficiency of gene disruption.


Assuntos
Sistemas CRISPR-Cas , Edição de Genes , Ribonucleoproteínas/metabolismo , Tecidos Suporte , Adesivos/química , Animais , Proteína 9 Associada à CRISPR/química , Linhagem Celular , Expressão Gênica , Técnicas de Transferência de Genes , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Lipídeos/química , Substâncias Macromoleculares/química , Substâncias Macromoleculares/metabolismo , Nanofibras/química , RNA Guia/química , RNA Guia/genética , Ribonucleoproteínas/genética , Engenharia Tecidual , Tecidos Suporte/química
13.
Acta Odontol Latinoam ; 33(2): 135-142, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32920616

RESUMO

This study evaluated the influence of the mode and time of solvent evaporation on the tensile strength (TS), flexural strength (FS) and elastic modulus (EM) of two adhesive systems: Scotchbond Multipurpose (SBMP) and Clearfil SE (CSEB). For this purpose, rectangular samples (2x1x7 mm) were prepared with 10 µL of primer and the solvents were evaporated with air spray at (23±1) ºC, (40±1) ºC and negative control (without spray). For each temperature, the times of 5, 20, 30, and 60 seconds were investigated. The statistical results showed that evaporation at 40±1ºC resulted in better EM for the two adhesives tested and all the evaporation times evaluated. However, there were no significant differences between the times and modes of evaporation for TS. The results of this study indicate that evaporation at a temperature of (40±1) °C could improve the elastic modulus of both adhesives tested, regardless of the evaporating time.


Assuntos
Adesivos/química , Cimentos Dentários/química , Adesivos Dentinários/química , Solventes/farmacologia , Resistência à Tração , Dessecação , Humanos , Teste de Materiais , Volatilização
14.
Niger J Clin Pract ; 23(8): 1148-1154, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32788494

RESUMO

Aims: The effect of mechanical loading on the microtensile bond strength (µTBS) of universal adhesives to dentin was evaluated in this study. Methods and Materials: Human molar teeth had the occlusal dentin surfaces exposed and were allocated into ten groups (five experimental groups and five control groups) that used the following universal adhesive systems in self-etch mode: All-Bond Universal (ABU), Single Bond Universal (SBU), Gluma Bond Universal (GBU), Tetric N-Bond Universal (TBU), and Clearfil Universal Bond (CUB). Following the bonding procedures and build-ups, the specimens were either stored in water at 37°C for 24 h or were mechanically loaded (50 N for 60,000 cycles) prior to the µTBS test. Data were analyzed using the one-way analysis of variance (ANOVA) and Tukey's posthoc test (P = 0.05). Results: Both the adhesive type and mechanical loading had significant effects on the µTBS (P < 0.05). The µTBS values of SBU and ABU were significantly higher than the values of the other adhesives (P < 0.05). However, the µTBS values of ABU decreased significantly after mechanical loading (P < 0.05). Conclusions: With the exception of ABU, mechanical loading had no deleterious effects on the µTBS of the universal adhesive systems examined in this study.


Assuntos
Adesivos/química , Colagem Dentária/métodos , Adesivos Dentinários/química , Bis-Fenol A-Glicidil Metacrilato , Resinas Compostas , Glutaral , Humanos , Teste de Materiais/métodos , Dente Molar , Ácidos Polimetacrílicos , Cimentos de Resina/química , Resistência à Tração
15.
Nat Commun ; 11(1): 3895, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32753588

RESUMO

The mussel byssus has long been a source of inspiration for the adhesion community. Recently, adhesive synergy between flanking lysine (Lys, K) and 3,4-Dihydroxyphenylalanine (DOPA, Y) residues in the mussel foot proteins (Mfps) has been highlighted. However, the complex topological relationship of DOPA and Lys as well as the interfacial adhesive roles of other amino acids have been understudied. Herein, we study adhesion of Lys and DOPA-containing peptides to organic and inorganic substrates using single-molecule force spectroscopy (SMFS). We show that a modest increase in peptide length, from KY to (KY)3, increases adhesion strength to TiO2. Surprisingly, further increase in peptide length offers no additional benefit. Additionally, comparison of adhesion of dipeptides containing Lys and either DOPA (KY) or phenylalanine (KF) shows that DOPA is stronger and more versatile. We furthermore demonstrate that incorporating a nonadhesive spacer between (KY) repeats can mimic the hidden length in the Mfp and act as an effective strategy to dissipate energy.


Assuntos
Adesivos/química , Di-Hidroxifenilalanina/química , Lisina/química , Sequência de Aminoácidos , Animais , Bivalves , Dipeptídeos , Peptídeos/síntese química , Propriedades de Superfície , Titânio/química
16.
J Vis Exp ; (161)2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32716389

RESUMO

The analysis of thermal processes associated to the curing of adhesives and the study of mechanical behavior once cured, provide key information to choose the best option for any specific application. The proposed methodology for the curing characterization, based on thermal analysis and rheology, is described through the comparison of three commercial adhesives. The experimental techniques used here are Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Rheology. TGA provides information about the thermal stability and filler content, DSC allows the evaluation of some thermal events associated to the cure reaction and to thermal changes of the cured material when subjected to temperature changes. Rheology complements the information of the thermal transformations from a mechanical point of view. Thus, the curing reaction can be tracked through the elastic modulus (mainly the storage modulus), the phase angle and the gap. In addition, it is also shown that although DSC is of no use to study the curing of moisture curable adhesives, it is a very convenient method to evaluate the low temperature glass transition of amorphous systems.


Assuntos
Adesivos/química , Varredura Diferencial de Calorimetria , Módulo de Elasticidade , Teste de Materiais , Reologia , Termogravimetria
17.
Proc Natl Acad Sci U S A ; 117(28): 16127-16137, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32601214

RESUMO

Thrombogenic reaction, aggressive smooth muscle cell (SMC) proliferation, and sluggish endothelial cell (EC) migration onto bioinert metal vascular stents make poststenting reendothelialization a dilemma. Here, we report an easy to perform, biomimetic surface engineering strategy for multiple functionalization of metal vascular stents. We first design and graft a clickable mussel-inspired peptide onto the stent surface via mussel-inspired adhesion. Then, two vasoactive moieties [i.e., the nitric-oxide (NO)-generating organoselenium (SeCA) and the endothelial progenitor cell (EPC)-targeting peptide (TPS)] are clicked onto the grafted surfaces via bioorthogonal conjugation. We optimize the blood and vascular cell compatibilities of the grafted surfaces through changing the SeCA/TPS feeding ratios. At the optimal ratio of 2:2, the surface-engineered stents demonstrate superior inhibition of thrombosis and SMC migration and proliferation, promotion of EPC recruitment, adhesion, and proliferation, as well as prevention of in-stent restenosis (ISR). Overall, our biomimetic surface engineering strategy represents a promising solution to address clinical complications of cardiovascular stents and other blood-contacting metal materials.


Assuntos
Adesivos/química , Materiais Revestidos Biocompatíveis/química , Peptídeos/química , Stents , Adesivos/síntese química , Animais , Materiais Biomiméticos/síntese química , Materiais Biomiméticos/química , Adesão Celular , Movimento Celular , Proliferação de Células , Células Cultivadas , Química Click , Células Progenitoras Endoteliais/citologia , Endotélio Vascular/citologia , Endotélio Vascular/fisiologia , Humanos , Miócitos de Músculo Liso/citologia , Óxido Nítrico/química , Compostos Organosselênicos/química , Peptídeos/síntese química , Proteínas/química , Coelhos , Stents/efeitos adversos , Trombose/etiologia , Trombose/prevenção & controle
18.
J Vis Exp ; (159)2020 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-32478730

RESUMO

The properties of cured wood adhesives are difficult to study because of the loss of water and other components to the wood, the influence of wood on the adhesive cure, and the effect of adhesive penetration on the wood interphase; thus, normal testing of a neat adhesive film is generally not useful. Most tests of wood adhesive bond strength are slow, laborious, can be strongly influenced by the wood and do not provide information on the kinetics of cure. Test method ASTM D 7998-19, however, can be used for fast evaluation of the strength of wood bonds. The use of a smooth, uniform, and strong wood surface, like maple face-veneer, and sufficient bonding pressure reduces the adhesion and wood strength effects on bond strength. This method has three main applications. The first is to provide consistent data on bond strength development. The second is to measure the dry and wet strengths of bonded lap shear samples. The third is to better understand the adhesive heat resistance by quickly evaluating thermal sensitivity and distinguishing between thermal softening and thermal degradation.


Assuntos
Adesivos/química , Teste de Materiais/métodos , Madeira/química , Resistência ao Cisalhamento
19.
AAPS PharmSciTech ; 21(4): 120, 2020 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-32323091

RESUMO

The objective of this study was to develop a simpler and more practical quantitative evaluation method of cold flow (CF) in transdermal drug delivery systems (TDDSs). CF was forcibly induced by loading a weight on a punched-out sample (bisoprolol and tulobuterol tapes). When the extent of CF was analyzed using the area of oozed adhesive as following a previously reported method, the CF profiles were looked different between the samples 12 mm in diameter subjected to a 0.5-kg weight and samples 24 mm in diameter subjected to a 2.0-kg weight despite an equal load per unit area (4.42 g/mm2). The width of oozed adhesive around the original sample was suggested to be an index that properly describes the relationship between the load per unit area and the extent of CF. Further, it was clarified that the average CF width over the entire circumference of the sample was the same whether the samples were round or square as long as the sample area and load were the same. We also observed a linear relationship between the CF width and the aspect ratio of oval and rectangular samples. These results indicated that the CF properties of typical TDDS products lacking CF-proof processing at the edges could be determined by testing samples cut from the product rather than the whole TDDS patch. The proposed width measuring method was simple and useful for optimizing the composition of the adhesive and for testing the quality of the product.


Assuntos
Adesivos/farmacocinética , Temperatura Baixa , Sistemas de Liberação de Medicamentos/métodos , Terbutalina/análogos & derivados , Adesivos/administração & dosagem , Adesivos/química , Administração Cutânea , Agonistas Adrenérgicos beta/administração & dosagem , Agonistas Adrenérgicos beta/química , Agonistas Adrenérgicos beta/farmacocinética , Avaliação Pré-Clínica de Medicamentos/métodos , Terbutalina/administração & dosagem , Terbutalina/química , Terbutalina/farmacocinética
20.
Biofouling ; 36(3): 245-255, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32326753

RESUMO

Dental plaque is a biofilm composed of a complex oral microbial community. The accumulation of plaque in the pit and fissures of dental elements often leads to the development of tooth decay (dental caries). Here, potent anti-biofilm materials were developed by incorporating zinc methacrylates or di-n-butyl-dimethacrylate-tin into the light-curable sealant and their physical, mechanical, and biological properties were evaluated. The data revealed that 5% di-n-butyl-dimethacrylate-tin (SnM 5%) incorporated sealant showed strong anti-biofilm efficacy against various single-species (Streptococcus mutans or Streptococcus oralis or Candida albicans) and S. mutans-C. albicans cross-kingdom dual-species biofilms without either impairing the mechanical properties of the sealant or causing cytotoxicities against mouse fibroblasts. The findings indicate that the incorporation of SnM 5% in the experimental pit and fissure self-adhesive sealant may have the potential to be part of current chemotherapeutic strategies to prevent the formation of cariogenic oral biofilms that cause dental caries.


Assuntos
Adesivos/farmacologia , Biofilmes/efeitos dos fármacos , Cárie Dentária/prevenção & controle , Selantes de Fossas e Fissuras/farmacologia , Zinco/química , Adesivos/química , Animais , Biofilmes/crescimento & desenvolvimento , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Cárie Dentária/microbiologia , Humanos , Metacrilatos/química , Camundongos , Microbiota/efeitos dos fármacos , Selantes de Fossas e Fissuras/química , Streptococcus mutans/efeitos dos fármacos , Streptococcus mutans/crescimento & desenvolvimento , Streptococcus oralis/efeitos dos fármacos , Streptococcus oralis/crescimento & desenvolvimento
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