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1.
Braz. j. oral sci ; 21: e225042, jan.-dez. 2022. ilus
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-1354728

RESUMO

Aim: Although bulk fill composites have been widely used as restorative material, there is no consensus regarding the best clinical protocol in terms of composite technique and adhesive system. Therefore, this clinical trial evaluated the clinical performance of bulk fill composites for class I restorations under different protocols. Methods: A randomized clinical trial including 155 class I restorations was conducted using different adhesive systems: conventional technique (phosphoric acid + conventional three-step adhesive system) (Group 1, 2 and 3); or self-etching adhesive system (Groups 4, 5 and 6). Control groups 1 and 4 were restored with conventional composite; groups 2 and 5 with low viscosity bulk fill and conventional composite as occlusal coverage; groups 3 and 6 with high viscosity bulk fill. The FDI criteria was used for clinical evaluation at baseline and after 6 months. Results: All groups showed good clinical performance. At baseline, the adhesive system did not affect postoperative hypersensitivity. After 6 months, group 5 showed a significant reduction in color and translucency; group 6 a reduction in terms of anatomical form and for postoperative sensitivity and an improvement in patient satisfaction (p<0.05). Considering the same restorative technique, the use of the self-etching adhesive system showed a significant decrease in color and translucency (p<0.05). Conclusion: All groups showed favorable clinical performance, and promising results were found for the conventional adhesive system and high viscosity bulk fill protocol


Assuntos
Ácidos Fosfóricos , Adesivos , Resinas Compostas , Restauração Dentária Permanente , Estética Dentária , Estudos Clínicos como Assunto
2.
Sensors (Basel) ; 22(11)2022 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-35684774

RESUMO

Structural health monitoring has multifold aims. Concerning composite structures, the main objectives are perhaps reducing costs by shifting from scheduled to on-demand maintenance and reducing weight by removing redundant precautions as the insertion of chicken fasteners to for ensuring joint safety in cases of bonding layer fail. Adhesion defects may be classified along different types, for instance distinguishing between glue deficiency or de-bonding. This paper deals with a preliminary numerical characterization of adhesive layer imperfections on a representative aircraft component. The multipart composite spar is made of two plates and two corresponding C-beams, bonded together to form an almost squared boxed section beam. A numerical test campaign was devoted to extract relevant information from different defect layouts and to try to assess some parameters that could describe their peculiarities. A focus was then given to macroscopic evidence of fault effects behavior, as localization, reciprocal interference, impact on structural response, and so on. A proprietary code was finally used to retrieve the presence and size of the imperfections, correlating numerical outcomes with estimations. Activities were performed along OPTICOMS, a European project funded within the Clean Sky 2 Joint Technology Initiative (JTI).


Assuntos
Adesivos , Adesivos/química
3.
J Evol Biol ; 35(6): 879-890, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35694995

RESUMO

Orb weaving spiders employ a 'silken toolkit' to accomplish a range of tasks, including retaining prey that strike their webs. This is accomplished by a viscous capture spiral thread that features tiny glue droplets, supported by a pair of elastic flagelliform fibres. Each droplet contains a glycoprotein core responsible for adhesion. However, prey retention relies on the integrated performance of multiple glue droplets and their supporting fibres, with previous studies demonstrating that a suspension bridge forms, whose biomechanics sum the adhesive forces of multiple droplets while dissipating the energy of the struggling insect. While the interdependence of the droplet's glycoprotein and flagelliform fibres for functional adhesion is acknowledged, there has been no direct test of this hypothesized linkage between the material properties of each component. Spider mass, which differs greatly across orb weaving species, also has the potential to affect flagelliform fibre and glycoprotein material properties. Previous studies have linked spider mass to capture thread performance but have not examined the relationship between spider mass and thread material properties. We extend earlier studies to examine these relationships in 16 orb weaving species using phylogenetic generalized least squares. This analysis revealed that glycoprotein stiffness (elastic modulus) was correlated with flagelliform fibre stiffness, and that spider mass was related to the glycoprotein volume, flagelliform fibre cross-sectional area and droplets per unit thread length. By shaping the elastic moduli of glycoprotein adhesive and flagelliform fibres, natural selection has maintained the biomechanical integration of this adhesive system.


Assuntos
Aranhas , Adesivos , Animais , Glicoproteínas , Filogenia , Comportamento Predatório , Seda , Aranhas/genética
4.
PLoS One ; 17(6): e0269552, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35666755

RESUMO

Cancer cell adhesion to the endothelium is a crucial process in hematogenous metastasis, but how the integrity of the endothelial barrier and endothelial cell (EC) mechanical properties influence the adhesion between metastatic cancer cells and the endothelium remain unclear. In the present study, we have measured the adhesion between single cancer cells and two types of ECs at various growth states and their mechanical properties (elasticity) using atomic force microscopy single cell force spectroscopy. We demonstrated that the EC stiffness increased and adhesion with cancer cells decreased, as ECs grew from a single cell to a confluent state and developed cell-cell contacts, but this was reversed when confluent cells returned to a single state in a scratch assay. Our results suggest that the integrity of the endothelial barrier is an important factor in reducing the ability of the metastatic tumor cells to adhere to the vascular endothelium, extravasate and lodge in the vasculature of a distant organ where secondary metastatic tumors would develop.


Assuntos
Adesivos , Neoplasias , Adesão Celular , Comunicação Celular , Células Endoteliais , Endotélio Vascular/metabolismo , Humanos , Neoplasias/metabolismo
5.
Carbohydr Polym ; 292: 119681, 2022 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-35725211

RESUMO

One of the key steps towards a broader implementation of renewable materials is the development of biodegradable adhesives that can be attained at scale and utilized safely. Recently, cellulose nanocrystals (CNCs) were demonstrated to have remarkable adhesive properties. Herein, we study three classes of naturally synthesized biopolymers as adhesives, namely nanocelluloses (CNFs), cellulose derivatives, and proteins by themselves and when used as additives with CNCs. Among the samples evaluated, the adhesion strength was the highest for bovine serum albumin and hydroxypropyl cellulose (beyond 10 MPa). These were followed by carboxymethylcellulose and CNCs (ca. 5 MPa) and mechanically fibrillated CNFs (ca. 2 MPa), and finally by tempo-oxidized CNFs (0.2 MPa) and lysozyme (1.5 MPa). Remarkably, we find that the anisotropy of adhesion (in plane vs out of plane) falls within a narrow range across the bio-based adhesives studied. Collectively, this study benchmarks bio-based non-covalent adhesives aiming towards their improvement and implementation.


Assuntos
Benchmarking , Nanopartículas , Adesivos , Celulose/química , Nanopartículas/química , Soroalbumina Bovina
6.
Sci Rep ; 12(1): 10272, 2022 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-35715694

RESUMO

This study investigated the potential of adhesive coating for hindering the reactivity of ion-releasing dental restorative materials. Experimental composites were prepared by replacing 10 or 20 wt% of reinforcing fillers with two types of bioactive glass. A glass ionomer, a giomer, and an alkasite were used as representatives of commercial ion-releasing materials. Restorative material specimens were coated with an etch-and-rinse adhesive, 1-step self-etch adhesive, 2-step self-etch adhesive, or left uncoated. The specimens were immersed in a lactic acid solution and ion concentrations were measured in 4 days intervals for 32 days (atomic absorption spectrometry for calcium, UV-Vis spectrometry for phosphate, ion-selective electrode for fluoride, and pH-meter for pH values). The adhesive coating reduced ion release between 0.3 and 307 times, in a significantly material- and adhesive-dependent manner. Fluoride release was most highly impaired, with the reduction of up to 307 times, followed by phosphate and calcium release, which were reduced up to 90 and 45 times, respectively. The effect of different adhesive systems was most pronounced for phosphate release, with the following rankings: uncoated ≥ 2-step self-etch adhesive ≥ 1-step self-etch adhesive ≥ etch-and-rinse adhesive. The differences among adhesives were less pronounced for calcium and fluoride. It was concluded that the resinous adhesive layer can act as a barrier for ion release and diminish the beneficial effects of remineralizing restorative materials.


Assuntos
Fluoretos , Cimentos de Resina , Adesivos , Cálcio , Resinas Compostas/química , Fluoretos/química , Teste de Materiais , Fosfatos , Cimentos de Resina/química
7.
Carbohydr Polym ; 291: 119572, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35698337

RESUMO

Integrating functionalities such as adhesiveness, self-healing, and conductivity on a polysaccharide-based hydrogel is highly desirable for ever-expanding practical applications, but there is always a challenge. Herein, an elaborately designed nanocomposite hydrogel is fabricated by the addition of highly conductive Ti3C2Tx MXene nanosheets into chondroitin sulfate (CS)/N, N-dimethylamino ethyl acrylate (DMAEA-Q) hydrogel network. Owing to the introduction of sulfonated Ti3C2Tx MXene nanosheets, the as-prepared nanocomposite hydrogels exhibit excellent stretchability (> 5000% strain), rapid self-healing ability (< 60 s), and high adhesiveness (≈ 100 kPa). The proposed hydrogel demonstrates an outstanding electrical conductivity up to 5.33 S/m, allowing real-time monitoring of the bending and stretching movements and full recovery. Furthermore, the SMC hydrogels exhibit fast and stable photothermal conversion performance due to the inherent photothermal behavior. Notably, multifunctional SMC hydrogels present real-time and reversible humidity sensing upon H2O-induced swelling/contraction of nanochannels between the Ti3C2Tx MXene interlayers, enabling respiration monitoring applications.


Assuntos
Adesivos , Hidrogéis , Condutividade Elétrica , Polissacarídeos , Titânio
8.
Adv Colloid Interface Sci ; 305: 102706, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35623113

RESUMO

The bone adhesive is a clinical requirement for complicated bone fractures always articulated by surgeons. Applying glue is a quick and easy way to fix broken bones. Adhesives, unlike conventional fixation methods such as wires and sutures, improve healing conditions and reduce postoperative pain by creating a complete connection at the fractured joint. Despite many efforts in the field of bone adhesives, the creation of a successful adhesive with robust adhesion and appropriate bioactivity for the treatment of bone fractures is still in its infancy. Because of the resemblance of the body's humid environment to the underwater environment, in the latest decades, researchers have pursued inspiration from nature to develop strong bioactive adhesives for bone tissue. The aim of this review article is to discuss the recent state of the art in bone adhesives with a specific focus on biomimetic adhesives, their action mechanisms, and upcoming perspective. Firstly, the adhesive biomaterials with specific affinity to bone tissue are introduced and their rational design is studied. Consequently, various types of synthetic and natural bioadhesives for bone tissue are comprehensively overviewed. Then, bioinspired-adhesives are described, highlighting relevant structures and examples of biomimetic adhesives mainly made of DOPA and the complex coacervates inspired by proteins secreted in mussel and sandcastle worms, respectively. Finally, this article overviews the challenges of the current bioadhesives and the future research for the improvement of the properties of biomimetic adhesives for use as bone adhesives.


Assuntos
Bivalves , Fraturas Ósseas , Adesivos/química , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Bivalves/química , Osso e Ossos
9.
Acta Biomater ; 146: 80-93, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35500814

RESUMO

Postoperative adhesion is a serious and frequent complication, but there is currently no reliable anti-adhesive barrier available due to low tissue adhesiveness, undesirable chemical reactions, and poor operability. To overcome these problems, we report a single-syringe hotmelt tissue adhesive that dissolves upon warming over 40 °C and coheres at 37 °C as a postoperative barrier. Tendon-derived gelatin was conjugated with the ureidopyrimidinone unit to supramolecularly control the sol-gel transition behavior. This functionalization improved bulk mechanical strength, tissue-adhesive properties, and stability under physiological conditions through the augmentation of intermolecular hydrogen bonding by ureidopyrimidinone unit. This biocompatible adhesive prevented postoperative adhesion between cecum and abdominal wall in adhesion models of rats. This hotmelt tissue adhesive has enormous potential to prevent postoperative complications and may contribute to minimally invasive surgery. STATEMENT OF SIGNIFICANCE: There is a strong need to develop medical tissue adhesives with high biocompatibility, tissue adhesiveness, and operatability to prevent postoperative complications. In this report, single syringe, hotmelt-type tissue adhesive was developed by controlling sol-gel transition behavior of gelatin through supramolecular approach. The functionalization of gelatin with quadruple hydrogen bonding improved key features necessary for anti-adhesive barrier including bulk mechanical strength, tissue adhesive property, stability under physiological conditions, and anti-adhesive property. The hotmelt tissue adhesive can be used for a sealant, hemostatic reagent, and wound dressing to prevent postoperative complications including delayed bleeding, perforation, and inflammation and contribute to minimally invasive surgery.


Assuntos
Adesivos Teciduais , Adesivos/química , Animais , Gelatina/química , Complicações Pós-Operatórias/prevenção & controle , Ratos , Aderências Teciduais/prevenção & controle , Adesivos Teciduais/química
10.
Int J Biol Macromol ; 212: 275-282, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35594941

RESUMO

Soft and elastic polymer hydrogel materials are booming in the fields of wearable biomimetic skin, sensors, robotics, and bioelectrodes. Currently, many researchers are exploring new chemistries for the preparation of hydrogels to improve their performance. In the present study, we design and develop a strategy to prepare lignin reinforced hydrogels based on disulfide bond crosslinking mechanisms, and resultant hydrogels exhibit excellent stretchability, with tensile strain of up to 1085.4%, and high adhesion (with the highest T-peel strength of up to 432.2 N/m to pigskin). The underlying mechanism is based on the disulfide bonds that act as crosslinkers in the as-prepared hydrogel, and they can be easily cleaved and re-formed under mild conditions. Thanks to the presence of lignin, the as-obtained hydrogels also have excellent UV shielding effect. When assembled into a strain sensor, they can output stable and sensitive sensing signals, with gauge factor (GF) of 2.72 (strain: 0-72.8%). Furthermore, a simple and effective strategy to construct asymmetric adhesive hydrogels was adopted, which is based on directional soaking of the top portion of the hydrogel in a high-concentrated calcium chloride solution. The asymmetric hydrogel strain sensor transmits accurate and stable signals without the interference of various contaminants.


Assuntos
Hidrogéis , Lignina , Adesivos/química , Dissulfetos , Condutividade Elétrica , Hidrogéis/química
11.
ACS Appl Mater Interfaces ; 14(22): 25115-25125, 2022 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-35609008

RESUMO

For rapid and effective hemostasis of uncontrollable bleeding, versatile hemostatic agents have been emerging. Among them, polyphenol-derived adhesives have attracted those hemostatic materials due to instantaneous formation of sticky barriers by robust interactions between the material and the serum proteins from wound. However, a critical challenge in such phenolic materials lies in long-term storage due to spontaneous oxidation under humid environments, leading to changes in hemostatic capability and adhesive strength. Here, we report a transparent hemostatic film consisting of gallol-conjugated chitosan (CHI-G) for minimizing the phenolic oxidation even for 3 months and maintaining strong tissue adhesiveness and its hemostatic ability. The film undergoes a phase transition from solid to injectable hydrogels at physiological pH for efficiently stopping internal and external hemorrhage. Interestingly, the hemostatic capability of the CHI-G hydrogels after 3 month storage depends on (i) the folded microstructure of the polymer with optimal gallol modification and (ii) an initial phase of either a solution state or a solid film. When the hydrogels are originated from the dehydrated film, their successful hemostasis is observed in a liver bleeding model. Our finding would provide an insight for design rationale of hemostatic formulations with long shelf-life.


Assuntos
Quitosana , Hemostáticos , Adesivos Teciduais , Adesivos/química , Quitosana/química , Hemorragia/tratamento farmacológico , Hemostasia , Hemostáticos/química , Hemostáticos/farmacologia , Hemostáticos/uso terapêutico , Humanos , Hidrogéis/química , Hidrogéis/farmacologia , Polifenóis/farmacologia , Adesivos Teciduais/química
12.
ACS Appl Mater Interfaces ; 14(22): 26287-26294, 2022 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-35617310

RESUMO

Developing new underwater glue adhesives with robust and repeatable adhesion to various surfaces is promising and useful in marine life and medical treatments. In this work, we developed a novel glue based on a copolymer with a cation-co-aromatic sequence where the cationic units contain both catechol and positively charged sites. The glue consists of a crosslinked copolymer of poly(2-hydroxy-3-phenoxypropyl acrylate-co-3-(5-(3,4 dihydroxyphenyl)-4-oxo-3 N-pentyl)imidazolium) bromide in dimethyl sulfoxide. Solidification of the glue, triggered by contact with water, undergoes a coacervation stage and causes a drastic growth of its mechanical properties over time. The glue demonstrates fast-developing, strong, and repeatable underwater adhesion to different materials and can maintain its strength for a long time. The adhesion strength tends to increase with the surface energy of the substrate material, to a maximum value of 160 kPa found in plywood. Experiments conducted in aqueous media with different pH and ionic strengths, including physiological conditions and seawater, showed an even stronger adhesion than that evolved in deionized water. Thus, the developed glue is a promising candidate for use in marine life, tissue adhesives, and other freshwater and saline water applications.


Assuntos
Adesivos , Polímeros , Adesivos/química , Cátions , Polímeros/química
13.
Nano Lett ; 22(11): 4482-4490, 2022 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-35580197

RESUMO

Comfort and mechanical stability are vital for epidermal electronics in daily use. In situ deposition of circuitry without the protection of substrates or encapsulation can produce imperceptible, conformal, and permeable epidermal electronics. However, they are easily destroyed by daily wear because the binding force between deposited materials and skin is usually weak. Here, we in situ deposited skin-adhesive liquid metal particles (ALMP) to fabricate epidermal electronics with robust wear resistance. It represents the most wear-resistant in situ deposited epidermal electronic materials. It can withstand ∼1600 cm, 175 g loaded paper tape wearing by a standard abrasion wear tester. Stretchability, conformality, permeability, and thinness of the ALMP coating provide an imperceptible and comfortable wearing experience. Without degradation of electrical property caused by solvent evaporation, the dry ALMP coating possesses natural advantages over gel electrodes. In situ deposited ALMP is an ideal material for fabricating comfortable epidermal electronics.


Assuntos
Adesivos , Eletrônica , Eletrodos , Metais , Pele
14.
Langmuir ; 38(22): 7013-7023, 2022 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-35613322

RESUMO

Hydrogel-based sensors serve as an ideal platform for developing personalized wearable electronics due to their high flexibility and conformability. However, the weak stretchability and inferior conductivity of hydrogels have severely restricted their large-scale application. Herein, a natural polymer-based conductive hydrogel integrated with favorable mechanical properties, good adhesive performance, and excellent fatigue resistance was fabricated via interpenetrating tannic acid (TA) into a chitosan (CS) cross-linked network in an acidic aqueous solution. The hydrogel was composed of a regular hierarchical porous structure, which was built by the hydrogen bonding between TA and CS. In addition, the hydrogels exhibited adjustable mechanical properties (maximum yield stress of 7000 Pa) and good stretchability (strain up to 320%). Benefiting from the abundant catechol groups of TA, the proposed hydrogels could repeatedly adhere to various material surfaces and could be easily peeled off without residue. Moreover, the hydrogel exhibited stable conductivity, high stretching sensitivity (gauge factor of 2.956), rapid response time (930 ms), and excellent durability (>300 cycles), which can be assembled as a strain sensor to attach to the human body for precise monitoring of human exercise behavior, distinguishing physiological signals, and recognizing speech. Furthermore, the prepared hydrogels also exhibited stable sensing performance to temperature. As a result, the hydrogels exhibited dual sensory performance for both temperature and strain deformation. It is anticipated that the incorporation of strain sensors and thermal sensors will provide theoretical guidance for developing multifunctional conductive hydrogels and pave a way for the versatile application of hydrogel-based flexible sensors in wearable devices and soft actuators.


Assuntos
Quitosana , Dispositivos Eletrônicos Vestíveis , Adesivos/química , Condutividade Elétrica , Humanos , Hidrogéis/química , Movimento (Física) , Taninos/química
15.
Sensors (Basel) ; 22(10)2022 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-35632269

RESUMO

In this study, the surface parameters wettability, roughness, and adhesive penetration, which are important for wood bonding, were investigated and evaluated utilizing non-destructive methods after different mechanical processing. For this purpose, beech and birch finger joints were prepared with different cutting combinations (three cutters with different sharpness levels and two feed rates) in an industrial process. Effects and interactions on the surface parameters resulting from the different cutting combinations were evaluated using three Full Factorial Designs. The various cutting parameters had a predominantly significant influence on the surface parameters. The effects and identified interactions highlight the complexity of the cutting surface and the importance of wood bonding. In this respect, a new finding is that with sharper cutters, higher contact angles of the adhesives occur. The methods (contact angle measurement, laser scanning microscopy, and brightfield microscopy) used were well suited to make effects visible and quantifiable, which can be of interest for the quality control of the wood processing industry. The results can help to better understand and evaluate the design of wood surfaces via machining and the bonding of hardwoods. Possibly the results can contribute to further standardizing the production of load-bearing hardwood finger joints and making them more efficient.


Assuntos
Articulações dos Dedos , Madeira , Adesivos , Propriedades de Superfície , Molhabilidade
16.
ACS Appl Bio Mater ; 5(6): 2880-2893, 2022 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-35583459

RESUMO

Malva sylvestris (MS) is a medicinal herb known worldwide for its beneficial effects due to the several active molecules present in its leaves and flowers. These compounds have shown antioxidant and anti-inflammatory properties and thus can be helpful in treatments of burns and chronic wounds, characterized mainly by high levels of free radicals and impairments of the inflammatory response. In this work, we propose bilayer films as wound dressings, based on poly(vinylpyrrolidone) (PVP) and sodium alginate loaded with M. sylvestris extracts from leaves and flowers and fabricated by combining solvent-casting and rod-coating methods. The top layer is produced in two different PVP/alginate ratios and loaded with the MS flowers' extract, while the bottom layer is composed of PVP and MS leaves' extract. The bilayers were characterized morphologically, chemically, and mechanically, while they showed superior self-adhesive properties on human skin compared to a commercial skin patch. The materials showed antioxidant activity, release of the bioactive compounds, and water uptake property. Moreover, the anthocyanin content of the flower extract provided the films with the ability to change color when immersed in buffers of different pH levels. In vitro tests using primary keratinocytes demonstrated the biocompatibility of the MS bilayer materials and their capacity to enhance the proliferation of the cells in a wound scratch model. Finally, the best performing MS bilayer sample with a PVP/alginate ratio of 70:30 was evaluated in mice models, showing suitable resorption properties and the capacity to reduce the level of inflammatory mediators in UVB-induced burns when applied to an open wound. These outcomes suggest that the fabricated bilayer films loaded with M. sylvestris extracts are promising formulations as active and multifunctional dressings for treating skin disorders.


Assuntos
Queimaduras , Malva , Adesivos , Alginatos , Animais , Antioxidantes/farmacologia , Bandagens , Malva/química , Camundongos , Extratos Vegetais/farmacologia , Cimentos de Resina
18.
J Colloid Interface Sci ; 622: 612-624, 2022 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-35533477

RESUMO

HYPOTHESIS: Development of soft conductive materials has enabled the promising future of wearable electronics for motion sensing. However, conventional soft conductive materials typically lack robust adhesive and on-demand removable properties for a target substrate. Therefore, it is believed that the integration of superior mechanical properties, electrical conductivity, and tunable adhesive properties into hydrogels would support and improve their reliable sensing performance. EXPERIMENTS: A hydrogel ionic conductor composed of cationic micelles crosslinked in the polyacrylamide (PAM) network was designed and fabricated. The viscoelastic, mechanical, adhesion, electrical, and antimicrobial properties of the hydrogel were systematically characterized. FINDINGS: The developed ionic conductor possesses a range of desirable properties including mechanical performances such as excellent stretchability (>1100%), toughness, elasticity (recovery from 1000% strain), conductivity (2.72 S·m-1), and antimicrobial property, owing to the multiple non-covalent supramolecular interactions (e.g., hydrogen bonding, hydrophobic, and π-π/cation-π interactions) present in the cross-linked network. Meanwhile, the developed hydrogel is incorporated with different stimuli-responsive polymers and exhibits a tunable adhesive property (triggerable attachment and on-demand removable capabilities) in adapt to the surrounding environmental conditions (i.e., pH, temperature). With all these significant features, the resulting hydrogel ionic conductor serves as a proof-of-concept motion-sensing system with excellent sensitivity and enhanced reliability for the detection of a wide range of motions.


Assuntos
Anti-Infecciosos , Hidrogéis , Adesivos/química , Anti-Infecciosos/farmacologia , Condutividade Elétrica , Hidrogéis/química , Íons/química , Reprodutibilidade dos Testes
19.
Sci Rep ; 12(1): 7560, 2022 05 09.
Artigo em Inglês | MEDLINE | ID: mdl-35534598

RESUMO

This work reveals a versatile new method to produce films with antimicrobial properties that can also bond materials together with robust tensile adhesive strength. Specifically, we demonstrate the formation of coatings by using a dielectric barrier discharge (DBD) plasma to convert a liquid small-molecule precursor, m-cresol, to a solid film via plasma-assisted on-surface polymerisation. The films are quite appealing from a sustainability perspective: they are produced using a low-energy process and from a molecule produced in abundance as a by-product of coal tar processing. This process consumes only 1.5 Wh of electricity to create a 1 cm2 film, which is much lower than other methods commonly used for film deposition, such as chemical vapour deposition (CVD). Plasma treatments were performed in plain air without the need for any carrier or precursor gas, with a variety of exposure durations. By varying the plasma parameters, it is possible to modify both the adhesive property of the film, which is at a maximum at a 1 min plasma exposure, and the antimicrobial property of the film against Escherichia coli, which is at a maximum at a 30 s exposure.


Assuntos
Adesivos , Anti-Infecciosos , Antibacterianos/química , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Cresóis , Escherichia coli
20.
Environ Res ; 212(Pt C): 113407, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35523281

RESUMO

Bacterial contamination of water environments can cause various troubles in various areas. As one of potential solutions, we develop enzyme-immobilized elastomer, and demonstrate the uses of enzyme reactions on-demand for effective microbial decontamination and antifouling. Asymmetrically-structured elastomer is prepared by combining two polydimethylsiloxane (PDMS) layers with different degrees of crosslinking: highly-crosslinked and lightly-crosslinked PDMS layers. At the surface of highly-crosslinked PDMS layer, porous structure with average diameter of 842 nm is formed by dissolving pre-packed and entrapped latex beads. Lightly-crosslinked PDMS on the other side, due to its adhesive nature, enables iterative attachments on various materials under either dry or wet condition. Glucose oxidase (GOx) is immobilized by using the pores at the surface of highly-crosslinked PDMS matrix via a ship-in-a-bottle protocol of precipitation-based microscale enzyme reactor (p-MER), which consists of GOx adsorption, precipitation and chemical crosslinking (EAPC). As a result, crosslinked enzyme aggregates (CLEAs) of GOx not only are well entrapped within many pores of highly-crosslinked PDMS layer (ship-in-bottle) but also cover the external surface of matrix, both of which are well connected together. Highly-interconnected network of CLEAs themselves effectively prevents enzyme leaching, which shows the 25% residual activity of GOx under shaking at 200 rpm for 156 days after 48% initial drop of loosely-bound p-MER after 4 days. In presence of glucose, the underwater attachment of biocatalytic elastomer demonstrates the generation of hydrogen peroxide via p-MER-catalyzed glucose oxidation, exhibiting effective biocidal activities against both gram-positive S. aureus and gram-negative E. coli. Adhesion-induced GOx-catalyzed reaction also alleviates the biofouling of membrane, suggesting its extendibility to various engineering systems being suffered by biofouling. This study of biocatalytic elastomer has demonstrated its new opportunities for the facile and on-demand enzyme-catalyzed reactions in various environmental applications, such as bactericidal treatment, water treatment/purification, and pollutant degradation.


Assuntos
Incrustação Biológica , Adesivos , Incrustação Biológica/prevenção & controle , Descontaminação , Elastômeros , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Escherichia coli , Glucose , Glucose Oxidase/química , Glucose Oxidase/metabolismo , Porosidade , Staphylococcus aureus/metabolismo
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