Adhesive Agent Research Articles

Formation of RuO2 thin film using dopamine as a reducing, chelating, and adhesive agent simultaneously

We demonstrate a facile and seedless wet chemical process to deposit RuO2 thin film on a glass slide. The process entails the use of dopamine and its oxidized form, polydopamine (PDA), as the reducing and chelating agent, as well as the adhesive agent bonding the RuO2 and glass slide. The formula starts with the oxidation of K2RuCl5 to prepare RuO4 solution, followed by its reduction by dopamine to form chelated RuO2 colloids for the deposition of amorphous RuO2 thin film containing 26.5 at% hydrous RuO2 and 73.5 at% RuO2. After a mild Ar annealing, the RuO2 thin film exhibits a rutile phase with (110) preferred orientation. Elemental analysis indicates incomplete pyrolysis of PDA. Results from X-ray absorption spectroscopy confirm the presence of RuO4 and its transformation to RuO2. Electrochemical analysis of the adsorbed dopamine molecules on an ITO substrate validates the oxidative behavior of dopamine. The bonding strength of RuO2 thin film is determined by a tape-peeling test in which both the as-deposited and annealed RuO2 thin films show robust adhesion to the glass substrate.

Thromboinflammation Model-on-A-Chip by Whole Blood Microfluidics on Fixed Human Endothelium.

Microfluidic devices have an established role in the study of platelets and coagulation factors in thrombosis, with potential diagnostic applications. However, few microfluidic devices have assessed the contribution of neutrophils to thrombus formation, despite increasing knowledge of neutrophils’ importance in cardiovascular thrombosis. We describe a thromboinflammation model which uses straight channels, lined with fixed human umbilical vein endothelial cells, after treatment with tumour necrosis factor-alpha. Re-calcified whole blood is perfused over the endothelium at venous and arterial shear rate. Neutrophil adhesion, platelet and fibrin thrombus formation, is measured over time by the addition of fluorescent antibodies to a whole blood sample. Fixed endothelium retains surface expression of adhesion molecules ICAM-1 and E-Selectin. Neutrophils adhere preferentially to platelet thrombi on the endothelium. Inhibitors of neutrophil adhesion and anti-inflammatory agents, such as isoquercetin, decrease neutrophil adhesion. Our model offers the advantage of the use of (1) fixed endothelium, (2) whole blood, instead of isolated neutrophils, and (3) a small amount of blood (1 mL). The characteristics of this thromboinflammation model provide the potential for further development for drug screening and point-of-care applications.

Characterization of dentin morphology after application of ozone and sodium ascorbate by scanning electron microscopy and atomic force microscopy

The aim of this study was to evaluate dentin morphology after ozone gas and sodium ascorbate application by the Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) images. Material and methods: Seven freshly extracted human third molars were sectioned perpendicularly to the tooth long axis, 3mm above the cementoenamel junction and other section above the first. Dentin slices were obtained, 2 mm thickness, then the slices were sectioned vertically and horizontally into four equal parts, resulting in 28 samples. These were divided in 4 groups (n=7): (G1) phosphoric acid – control; (G2) ozone + phosphoric acid; (G3) phosphoric acid + ozone; and (G4) ozone + sodium ascorbate + phosphoric acid. Dentin morphology of six samples of each groupwas evaluated by SEM and one by AFM. Results: In Groups 2 and 4 there was a change in the effectiveness of acid etching in terms of removing the smear layer. In Group 3 there was a change in the dentin microstructure, which can be a harmful factor regarding the bond strength of adhesive agents. Conclusion: After the qualitative analysis, the application sequences of ozone, phosphoric acid etching and sodium ascorbate application generated differences in the dentinmorphology by SEM and AFM. Sodium ascorbate decreased the ozone effect before the acid etching but did not eliminate it.

Ionic Fluoropolyphosphazenes as Potential Adhesive Agents for Dental Restoration Applications

Clinically, the use of photo-activated polymer-based dental composites is the preferred method to restore carious teeth due to their esthetics and ease of application. However, the longevity of these resin-based composite tooth restorations can be compromised by the sensitivity of the bonded interface between the composite and the tooth surface. The objective of the current study was to modify the tooth surface with novel fluorinated polyphosphazenes (PPZs), thereby improving the stability of the interface. Binding isotherms of PPZs with collagen (CLG) and hydroxyapatite (HA), two of the primary components of teeth, were established and indicate significant and stable adsorption to the surfaces of these materials. PPZs were also shown to protect CLG against acidic dissolution in a model system. A composite material consisting of the fluorinated polymer and CLG demonstrated three-dimensional stability and significant hydrophobicity. Additionally, no hemolytic activity was observed when evaluated using a porcine red blood cells (RBC) assay. Bovine dentin treated with PPZs demonstrated increased contact angle (hydrophobicity) compared with control samples and resisted fluid penetration when assessed using a dye penetration study. Finally, microhardness evaluation of bovine dentin treated with PPZs and exposed to an acidic challenge showed that treated dentin resisted demineralization. The hardness of the untreated control was significantly reduced after exposure when compared with the PPZ-treated samples. This study represents a novel approach to overcoming the current limitations of composite restorations. These results are promising to improve the longevity of composite dental restorations and may have wider use in sealants, varnishes, and other dental applications. Tooth decay remains a prevalent problem worldwide. Polymer-based composites are the most frequently used tooth restorative used in the clinic. The longevity of these fillings is limited due to conditions in the mouth that can weaken the adhesive used to bond the composite to the natural tooth. The current study uses novel polyphosphazenes (PPZs), hybrid organic-inorganic macromolecules with tunable hydrophilic-hydrophobic properties to coat the tooth surface to achieve better compatibility with the adhesive, thereby improving the longevity of the restoration. Results indicate that PPZs have significant and stable adsorption onto teeth, which may lead to a more stable bonded interface.

In‐situ synthesis and adhesion method to prepare phosphorous–nitrogen compounds flame‐retardant wood pulp paper with high efficiency and durability

SummaryIn the present work, flame‐retardant wood pulp paper (WPP) with high water resistance was fabricated through in‐situ synthesis and adhesion of flame retardant on the lignocellulose fibers. Through a simple solution spraying method, melamine (Me) and polyphosphoric acid solution were adequately permeated into interior lignocellulose fibers of WPP in turn and then reacted to produce water‐insoluble phosphorous–nitrogen melamine polyphosphate (MPP). The finally sprayed melamine formaldehyde prepolymer played the roles of flame‐retardant coating, adhesive agent, and water‐proofing layer, thus bonding MPP particles to the lignocellulose fibers firmly. This low‐cost and efficient treatment endowed WPP with excellent flame retardance and satisfactory durability. It showed that the modified WPP had a high limiting oxygen index value of 37.3%, and achieved B‐0 rating in vertical burning test, as well as greatly lowered the peak heat release rate and the total heat release. The flame‐retardant mechanisms of the modified WPP were analyzed and discussed. Moreover, the flame retardance kept well after 72 hours of water resistance test, showing good combination between the flame‐retardant particles and the lignocellulose fibers.

The clinical effectiveness of adhesive agents in posterior restorations

The clinical effectiveness of adhesive agents has been mainly evaluated using class V restorations. Clinical studies evaluating adhesives in combination with posterior composites are scarce and of short-term periods. This paper is aimed to review the current literature on the clinical effectiveness of contemporary adhesives when used to restore posterior teeth (Class I and Class II). To conduct this review, Scopus, PubMed, and Google Scholar databases were used to search for peer-reviewed articles on the clinical performance of adhesive agents in posterior composite restorations. Search terms used included “adhesive agents,” “clinical evaluation,” “composite restorations,” “posterior teeth,” “self-etch adhesives,” “etch -and -rinse adhesives,” and “universal adhesives.” To enrich the results, reference mining of the articles that were identified was used to locate other papers. The process of cross-referencing continued until no new articles were identified. No limits were placed on the year of publication, but only articles in English were considered. The current review found that simplification in the adhesive technique so far seems to affect the clinical performance. There is a relative paucity of evidence relating to the performance of universal adhesive agents in posterior restorations. Further long-term clinical studies are needed to evaluate the clinical performance of adhesive agents.

Farklı Bağlayıcı Ajanlar Uygulanmış Lazer Sinterize Kobalt-Krom Alaşımına Kompozit Bağlantısının İncelenmesi

Farklı Bağlayıcı Ajanlar Uygulanmış Lazer Sinterize Kobalt-Krom Alaşımına Kompozit Bağlantısının İncelenmesi

Effect of hydrogel-based antibiotic intracanal medicaments on crown discoloration.

ObjectivesThis study evaluated the effects of low and moderate concentrations of triple antibiotic paste (TAP) and double antibiotic paste (DAP) loaded into a hydrogel system on crown discoloration and explored whether application of an adhesive bonding agent prevented crown discoloration.Materials and MethodsIntact human molars (n = 160) were horizontally sectioned 1 mm apical to the cementoenamel junction. The crowns were randomized into 8 experimental groups (calcium hydroxide, Ca[OH]2; 1, 10, and 1,000 mg/mL TAP and DAP; and no medicament. The pulp chambers in half of the samples were coated with an adhesive bonding agent before receiving the intracanal medicament. Color changes (ΔE) were detected by spectrophotometry after 1 day, 1 week, and 4 weeks, and after 5,000 thermal cycles, with ΔE = 3.7 as a perceptible threshold. The 1-sample t-test was used to determine the significance of color changes relative to 3.7. Analysis of variance was used to evaluate the effects of treatment, adhesive, and time on color change, and the level of significance was p < 0.05.ResultsCa(OH)2 and 1 and 10 mg/mL DAP did not cause clinically perceivable tooth discoloration. Adhesive agent use significantly decreased tooth discoloration in the 1,000 mg/mL TAP group up to 4 weeks. However, adhesive use did not significantly improve coronal discoloration after thermocycling when 1,000 mg/mL TAP was used.ConclusionsCa(OH)2 and 1 and 10 mg/mL DAP showed no clinical discoloration. Using an adhesive significantly improved coronal discoloration up to 4 weeks with 1,000 mg/mL TAP.

Evaluation of shear bond strength of various adhesives under Simulated intrapulpal pressure: An in vitro study.

Introduction:The presence of pulpal fluid can influence dentin bonding. This study aimed to evaluate the shear bond strength of universal dental adhesives under simulated intrapulpal pressure.Materials and Methods:Forty intact maxillary premolars were distributed into four groups (Group 1 – 3M ESPE Adper Single Bond 2 total etch adhesive, Group 2 – 3M ESPE Single Bond Universal, Group 3 – Prime and Bond universal adhesive, and Group 4 – Ivoclar Tetric N Bond Universal). Adhesive restorative procedures were carried under intrapulpal pressure simulation following which it was subjected to a shear load of 0.5 mm/min. Fracture mode analysis was performed using a stereomicroscope. The data obtained were subjected to ANOVA and Tukey post hoc test with a P < 0.05.Results:Highest bond strength was exhibited by Group 3 (7.01 ± 2.02 MPa) and least by Group 1 (5.36 ± 3.03 MPa). However, there were no statistical differences among the groups. Group 1 and 2 showed mostly cohesive failure, whereas Group 3 and 4 showed mixed failure.Conclusion:The results demonstrated that the experimental universal adhesive agents exhibited comparative shear bond strength when subjected to pulpal pressure. Pulpal pressure has a significant effect on bond strength.

An Experimental Investigation of Mechanical Properties of Bonded Concrete

This paper presents an experimental study to measure mechanical properties of bonded concrete specimens. The bond between freshly mixed and hardened concrete has been a concern in repair and retrofit projects as well as staged construction of concrete members. This concern has roots in the time-dependent behavior of concrete, beginning with early-age concrete and continuing with long-term performance and durability of concrete. Moreover, environmental conditions generally complicate the behavior of concrete and resulted deformations such as shrinkage and creep. Application of chemical adhesives and epoxies is a common technique to enhance the bond at the interface of old and new concrete elements. The presented methodology includes preparation of bonded specimens with application of grout and adhesive agents. Mechanical strengths of specimens have been reported based on compressive, tensile, flexural, and shear testing. Results indicate that bonding agents are more effective in tensile and shear behavior of bonded samples.

An Experimental Investigation of Mechanical Properties of Bonded Concrete

This paper presents an experimental study to measure mechanical properties of bonded concrete specimens. The bond between freshly mixed and hardened concrete has been a concern in repair and retrofit projects as well as staged construction of concrete members. This concern has roots in the time-dependent behavior of concrete, beginning with early-age concrete and continuing with long-term performance and durability of concrete. Moreover, environmental conditions generally complicate the behavior of concrete and resulted deformations such as shrinkage and creep. Application of chemical adhesives and epoxies is a common technique to enhance the bond at the interface of old and new concrete elements. The presented methodology includes preparation of bonded specimens with application of grout and adhesive agents. Mechanical strengths of specimens have been reported based on compressive, tensile, flexural, and shear testing. Results indicate that bonding agents are more effective in tensile and shear behavior of bonded samples.

Coumarin derivative trigger controlled photo-healing of ion gels and photo-controlled reversible adhesiveness

Fabrication strategies for photo-responsive ion gels have attracted attention owing to their precise spatial and temporal control with predetermined responses to light stimuli. In this work, a reversible light-driven method was introduced to devise photo-responsive ion gels by harnessing coumarin-based building blocks under 365 nm irradiation. A series of random copolymers composed of N, N-dimethylacrylamide (DMA) and 7-(2′-methacryloyloxyethoxy)–4-methylcoumarin (MAOEMC), namely P(DMA-r-MAOEMC), were synthesized through reversible addition-fragmentation chain transfer (RAFT) polymerization with sufficient molecular weight (≈100 kDa). The coumarin moieties in those polymers exhibited a reversible photo-induced dimerization and photocleavage behavior in 1-ethyl-3-methylimidazolium bis (trifluoromethylsufonyl) imide ([C2mim][NTf2]). Those polymers - ionic liquid system at high polymer concentration (20 wt%) under suitable wavelength UV light irradiation led to sol–gel transition, which could be functionalized as photo-healable material and photo-controlled adhesion agents. Notably, the photo-controlled adhesiveness was reversible and can be mediated from 1.2 MPa to 0.2 MPa. This work opens new avenues to develop multifunctional ion gels using dynamic covalent bonds.

Evolution of a Technology Standard Alliance Based on an Echo Model Developed through Complex Adaptive System Theory

The evolution of the technology standard alliance (TSA) is examined using complex adaptive system (CAS) theory. Taking TSA as a dynamic CAS, an echo model is constructed to depict the mechanism of its evolution, and a model is simulated on the NetLogo platform. The echo model includes a basic model, an extended model, and a three-layer echo model. The adhesive aggregation of agents is explained, and the three evolutionary stages of agents’ entry, migration, and exit are analyzed. Moreover, the adaptability of agents in TSA is quantified. The results of simulation show the evolution of the TSA in relation to the two aspects of agent adhesion aggregation and agent resource interaction, and they demonstrate the dynamic and complex hierarchical structure of the TSA system. It is proposed that greater matching ability, moderate behavior income, and lower behavior cost are more conducive to the evolution and development of TSA. Additionally, the echo model is reconstructed to expand the range of application of CAS theory.

Highly thermally conductive yet mechanically robust composites with nacre-mimetic structure prepared by evaporation-induced self-assembly approach

Highly thermally conductive and mechanically strong nanocomposites for efficient thermal management have received wide attention because of the rapid development of modern electronics. Boron nitride nanosheet (BNNS) with combined benefits of high thermal conductivity (TC) and good electrical insulation has been considered a promising filler to fabricate thermally conductive nanocomposites. Herein, inspired by biological systems, large-scale and high-performance artificial nacre-like composite composed of BNNS and oxidized cellulose nanocrystal (OCNC) is fabricated through simple evaporation-induced self-assembly (EISA) approach for the first time. Thanks to the template effect of OCNC host, BNNS and OCNC are self-assembled to form an artificial layer-by-layer nacre structure, where OCNC combined with the epoxy-based adhesive agent (AA) serves as the mortar to form a stiff and dense structure. The resulting BNNS-OCNC-AA composite at a relative low BNNS loading of 11.6 vol% exhibits a high in-plane thermal conductivity of 10.9 W/mK as well as the excellent tensile strength of 197.3 MPa, which are prominent compared to other composites fabricated via the various currently established methods under higher filler loadings (13.4 ~ 95 vol%). From the characterization results, we could attribute the multiple properties to the construction of the unique nacre-like structure and the robust interfacial interaction. The artificial nacre-like BNNS composite with excellent thermal and mechanical properties simultaneously has significant potential application for thermal management in flexible and wearable electronics fields.

Endovascular Treatment of Intracranial Dural Arteriovenous Fistulas: A German Single-Center Experience

Background and Purpose: Intracranial dural arteriovenous fistulas (DAVFs) are abnormal shunts between dural arteries and dural venous sinus or cortical veins. We report our experience with endovascular therapy of primary complex DAVFs using modern embolic agents. Methods: This is a retrospective analysis of patients with DAVFs treated between 2015 and 2019. Patient demographics and technical aspects including the use of embolic agent, access to the fistula, number of treatments, occlusion rates, and complications were addressed. Angiographic treatment success was defined as complete occlusion (CO) of the DAVF. Results: Fifty patients were treated endovascularly. Median age was 61 years and 66% were men. The most common symptom was pulsatile tinnitus in 17 patients (34%). The most frequent location of the DAVF was the transverse-sigmoid sinus (40%). Thirty-six fistulas (72%) had cortical venous reflux. Nonadhesive and adhesive liquid agents were used in 92% as a single material or in combination. CO was achieved in 48 patients (96%). In 28 individuals (56%), only 1 procedure was necessary. Nonadhesive liquid agents were exclusively used in 14 patients (28%) with CO attained in every case. For CO of tentorial DAVFs, multiple sessions were more often required than at the other locations (55 vs. 14%, p = 0.0051). Among 93 procedures, the overall complication rate was 3%. The procedure-related mortality rate was 0%. Conclusion: Endovascular treatment of intracranial DAVFs is feasible, safe, and effective with high rates of CO. In more than half of the patients, the DAVF was completely occluded after a single procedure. However, in tentorial DAVFs, multiple sessions were more often required.

Facile preparation of cellulose nanofiber derived carbon and reduced graphene oxide co-supported LiFePO4 nanocomposite as enhanced cathode material for lithium-ion battery

In this work, cellulose nanofiber (CNF) derived carbon and reduced graphene oxide co-supported lithium iron phosphate (LiFePO4, LFP) nanocomposite was prepared by thoroughly mixing CNF with LFP first, followed by mixing again with graphene oxide (GO) to make well dispersed LFP nanoparticles anchored on graphene oxide, finally heating under an inert atmosphere. The ultrathin CNF was used as not only a carbon source but also an adhesive agent which can attach the LFP nanoparticles to the graphene sheets. The LFP nanoparticles were tightly attached to graphene sheets due to the hydrogen bond between GO and CNF. This nanocomposite exhibited good rate performance (discharge capacity of 168.9 mA h g−1 at 0.1C, and 90.3 mA h g−1 at 60C) and long-term cycle stability (~ 91.5% of initial capacity at 10C after 500 cycles) as cathode material for LIBs. The good rate and cycling performances could be attributed to the well-connected electron pathway derived from strongly adhering the LFP nanoparticles to reduced graphene oxide (rGO) and the facilitate electron transportation derived from carbonized CNF (cCNF) conductive network. The introduction of cCNF to LFP/rGO nanocomposite can be a promising strategy for further improve the performance of LFP cathode in LIBs.

Effect of Surface Treatment on Interface Strength of CFRP/Metal Hybrid Composites

Recently, automobile components such as center pillars and impact beams have been fabricated using materials that satisfy both high strength and impact absorption. In this study, the forming process of CR340 (cold rolled steel)/CFRP hybrid composites was investigated. Initially, hybrid composites were fabricated by stacking carbon fibre reinforced plastic (CFRP) prepreg on CR340 steel with Zn coating. An adhesive agent developed by the research team was applied for bonding between the cold rolled steel and CFRP to enable the blank fabrication of hybrid composites. The mechanical properties of the developed hybrid composites were investigated by tensile, bending and lap shear adhesion test. The results showed that the tensile strength and shear strength of composites increases with the increase in the number of laminations but the bending strength decreases.

Convenient Design of Hollow Co3O4 Nanostructure on Carbon Cloth for Flexible Supercapacitors

We proposed a new approach to construct zeolitic imidazolate frameworks-67 (ZIF-67) powders directly on carbon cloth without any conductive agent and adhesion agent and the ZIF-67 nanoparticles on carbon cloth were successfully converted into hollow Co3O4 nanostructure via a facile calcination process. Compared with original ZIF-67 powders, the Co3O4@CC electrode materials had admirable specific capacitance of 1 164.8 F·g−1 at an area current density of 2.5 mA·cm−2. Furthermore, the rate performance remained 42.4% of initial value when the current density was increased to 30 mA·cm−2 and the specific capacitance maintained 93.4% of initial capacity after 5 000 cycles at an area current density of 10 mA·cm−2. This strategy may have potential prospect for the application of MOFs in the energy storage and conversion field.

Modification of carbon black pigment: Cotton fabric colouring and anti‐bacterial finishing

AbstractFunctional polymer modified carbon black (CB) pigment (P‐(DMC‐co‐CHPMA)‐g‐MPTS/CB) with reactive epoxy and quaternary ammonium groups was designed and prepared via a thiol‐ene click chemistry reaction, and its dispersion ability in the aqueous phase, as well as its colouring and anti‐bacterial properties for cotton fabrics, were investigated. In considering both dispersion ability and reactive ability to cotton fabric, the mole ratio of the monomers (methacrylatoethyl trimethyl ammonium chloride [DMC] and 3‐chloro‐2‐hydroxypropyl methacrylate [CHPMA]) was discussed. Morphology and chemical properties of P‐(DMC‐co‐CHPMA)‐g‐MPTS/CB were tested by scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis and X‐ray photoelectron spectroscopy, resulting in a weight content of copolymer (DMC‐co‐CHPMA) in P‐(DMC‐co‐CHPMA)‐g‐MPTS/CB of ca. 18%. P‐(DMC‐co‐CHPMA)‐g‐MPTS/CB was fixed onto cotton fabric via a nucleophilic‐substituted reaction between reactive epoxy groups on the CB surface and the hydroxyl groups of cotton fabric, which endowed good fastness to cotton fabric without either a fixing or an adhesive agent. Also, coloured cotton fabric demonstrated excellent anti‐bacterial activity towards Staphylococcus aureus and Escherichia coli O157:H7.

Bacterial outer membrane vesicles as a platform for biomedical applications: An update

Outer membrane vesicles (OMVs) are produced by Gram-negative bacteria both in vitro and in vivo. OMVs are nano-sized spherical vehicles formed by lipid bilayer membranes and contain multiple parent bacteria-derived components. Based on the presence of bacterial antigens, pathogen-associated molecular patterns (PAMPs), adhesins, various proteins and the vesicle structure, OMVs have been developed for biomedical applications as bacterial vaccines, adjuvants, cancer immunotherapy agents, drug delivery vehicles, and anti-bacteria adhesion agents. In this review, we analyze the contributions of the structure and composition of OMVs to their applications, summarize the methods used to isolate and characterize OMVs, and highlight recent progress and future perspectives of OMVs in biomedical applications.