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1.
Polymers (Basel) ; 16(10)2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38794591

RESUMO

This study introduces novel PETG-ABS-Fe3O4 nanocomposites that offer impressive 3D- and 4D-printing capabilities. These nanocomposites can be remotely stimulated through the application of a temperature-induced magnetic field. A direct granule-based FDM printer equipped with a pneumatic system to control the output melt flow is utilized to print the composites. This addresses challenges associated with using a high weight percentage of nanoparticles and the lack of control over geometry when producing precise and continuous filaments. SEM results showed that the interface of the matrix was smooth and uniform, and the increase in nanoparticles weakened the interface of the printed layers. The ultimate tensile strength (UTS) increased from 25.98 MPa for the pure PETG-ABS sample to 26.3 MPa and 27.05 MPa for the 10% and 15% Fe3O4 nanocomposites, respectively. This increase in tensile strength was accompanied by a decrease in elongation from 15.15% to 13.94% and 12.78%. The results of the shape-memory performance reveal that adding iron oxide not only enables indirect and remote recovery but also improves the shape-memory effect. Improving heat transfer and strengthening the elastic component can increase the rate and amount of shape recovery. Nanocomposites containing 20% iron oxide demonstrate superior shape-memory performance when subjected to direct heat stimulation and a magnetic field, despite exhibiting low print quality and poor tensile strength. Smart nanocomposites with magnetic remote-control capabilities provide opportunities for 4D printing in diverse industries, particularly in medicine, where rapid speed and remote control are essential for minimally invasive procedures.

2.
Int J Biol Macromol ; 270(Pt 2): 132386, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38754671

RESUMO

Due to the high concentration of various toxic and dangerous pollutants, industrial effluents have imposed increasing threats. Among the various processes for wastewater treatment, adsorption is widely used due to its simplicity, good treatment efficiency, availability of a wide range of adsorbents, and cost-effectiveness. Chitosan (CS) has received great attention as a pollutant adsorbent due to its low cost and many -OH and -NH2 functional groups that can bind heavy metal ions. However, weaknesses such as sensitivity to pH, low thermal stability and low mechanical strength, limit the application of CS in wastewater treatment. The modification of these functional groups can improve its performance via cross-linking and grafting agents. The porosity and specific surface area of CS in powder form are not ideal, so physical modification of CS via integration with other materials (e.g., metal oxide, zeolite, clay, etc.) leads to the creation of composite materials with improved absorption performance. This review provides reports on the application of CS and its nanocomposites (NCs) for the removal of various heavy metal ions. Synthesis strategy, adsorption mechanism and influencing factors on sorbents for heavy metals are discussed in detail.


Assuntos
Quitosana , Metais Pesados , Nanocompostos , Poluentes Químicos da Água , Purificação da Água , Quitosana/química , Metais Pesados/química , Metais Pesados/isolamento & purificação , Adsorção , Nanocompostos/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Águas Residuárias/química , Íons/química
3.
Int J Biol Macromol ; 256(Pt 2): 128445, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38029916

RESUMO

Preparation of reusable protic ionic liquid, triflic acid-immobilized aminoethyl piperazine-modified pectin (Pec-AEP-TfOH), with excellent activity and selectivity in modified Schmidt synthesis of nitriles from aldehydes and Si(CH3)3N3 has been described. The structure of the catalyst was characterized using FT-IR, XRD, FE-SEM, EDX-mapping, and TGA-DTA. The reaction demonstrated a broad substrate scope for a variety of benzaldehyde derivatives with electron withdrawing/donating substituents and heterocyclic aldehydes with yields between 85 and 96 % at room temperature. Also, the Pec-AEP-TfOH showed an excellent selectivity for the nitriles in which no formanilide was obtained. Furthermore, the Pec-AEP-TfOH revealed a remarkable chemoselectivity for aldehydes in the presence of acids or ketones. It is worth noting that TfOH as a precious superacid was immobilized for the first time in the selective Schmidt synthesis of nitriles to improve the eco-friendliness and economic efficiency of the process. Furthermore, the catalyst was cost-effective, metal-free, safe, scalable, and reusable (5 times) and its heterogeneity was confirmed by hot-filtration test.


Assuntos
Líquidos Iônicos , Mesilatos , Líquidos Iônicos/química , Nitrilas/química , Pectinas , Espectroscopia de Infravermelho com Transformada de Fourier , Aldeídos/química , Piperazinas
4.
Mater Today Bio ; 23: 100823, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37928254

RESUMO

Wound care and treatment can be critical from a clinical standpoint. While different strategies for the management and treatment of skin wounds have been developed, the limitations inherent in the current approaches necessitate the development of more effective alternative strategies. Advances in tissue engineering have resulted in the development of novel promising approaches for accelerating wound healing. The use of various biomaterials capable of accelerating the regeneration of damaged tissue is critical in tissue engineering. In this regard, cerium oxide nanoparticles (CeO2 NPs) have recently received much attention because of their excellent biological properties, such as antibacterial, anti-inflammatory, antioxidant, and angiogenic features. The incorporation of CeO2 NPs into various polymer-based scaffolds developed for wound healing applications has led to accelerated wound healing due to the presence of CeO2 NPs. This paper discusses the structure and functions of the skin, the wound healing process, different methods for the synthesis of CeO2 NPs, the biological properties of CeO2 NPs, the role of CeO2 NPs in wound healing, the use of scaffolds containing CeO2 NPs for wound healing applications, and the potential toxicity of CeO2 NPs.

5.
Polymers (Basel) ; 15(17)2023 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-37688243

RESUMO

This study investigated the relationship between the structure and mechanical properties of polycaprolactone (PCL) nanocomposites reinforced with baghdadite, a newly introduced bioactive agent. The baghdadite nanoparticles were synthesised using the sol-gel method and incorporated into PCL films using the solvent casting technique. The results showed that adding baghdadite to PCL improved the nanocomposites' tensile strength and elastic modulus, consistent with the results obtained from the prediction models of mechanical properties. The tensile strength increased from 16 to 21 MPa, and the elastic modulus enhanced from 149 to 194 MPa with fillers compared to test specimens without fillers. The thermal properties of the nanocomposites were also improved, with the degradation temperature increasing from 388 °C to 402 °C when 10% baghdadite was added to PCL. Furthermore, it was found that the nanocomposites containing baghdadite showed an apatite-like layer on their surfaces when exposed to simulated body solution (SBF) for 28 days, especially in the film containing 20% nanoparticles (PB20), which exhibited higher apatite density. The addition of baghdadite nanoparticles into pure PCL also improved the viability of MG63 cells, increasing the viability percentage on day five from 103 in PCL to 136 in PB20. Additionally, PB20 showed a favourable degradation rate in PBS solution, increasing mass loss from 2.63 to 4.08 per cent over four weeks. Overall, this study provides valuable insights into the structure-property relationships of biodegradable-bioactive nanocomposites, particularly those reinforced with new bioactive agents.

7.
Dent Res J (Isfahan) ; 20: 40, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37180684

RESUMO

Background: The digital dentistry, requires materials with wo opposite properties of machining ability and also enough hardness. The main objective of this experimental study was to investigate the fabrication feasibility of the lithium metasilicate glass-ceramic in partially crystalized stated using the spark plasma sintering (SPS) method. Materials and Methods: In this study, SPS for the first time was used to fabricate primary lithium metasilicate glass-ceramic (LMGC) blocks. The raw materials were mixed and melted and then quenched in water and the resulted frits were grinded. The resulting powder was sintered by SPS at 660, 680, and 700°C. Results: Scanning Electron Microscope (SEM), X-ray diffraction (XRD), and Vicker's microhardness assay were used to evaluate the properties of samples. Statistical comparison of the obtained data was performed by ANOVA, followed by the post hoc test of Duncan. Microstructural studies by SEM and XRD showed that all samples were composed of lithium metasilicate phase in a glassy matrix. With increasing the sintering temperature, the number and size of lithium metasilicate particles increased and higher mechanical properties have been achieved. However, the sintered sample at 700°C has less processing ability than the samples sintered at 660 and 680°C. Conclusion: The optimum sintering temperature for glass frit consolidation was determined by SPS at 680°C.

8.
Int J Biol Macromol ; 235: 123723, 2023 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-36801220

RESUMO

Regarding the existence of cationic and anionic dyes in the water environment developing new and effective techniques to remove them simultaneously is essential. Herein, a chitosan/poly-2-aminothiazole composite film reinforced with multi-walled carbon nanotube-Mg Al-layered double hydroxide (CPML) was created, characterized, and used as an effective adsorbent for methylene blue (MB) and methyl orange (MO) dyes removal from the aquatic medium. The SEM, TGA, FTIR, XRD, and BET methods were used to characterize the synthesized CPML. Response surface methodology (RSM) was utilized to evaluate dye removal based on the initial concentration, dosage, and pH factors. The highest adsorption capacities were measured at 471.12 and 230.87 mg g-1 for MB and MO, respectively. The study of different isotherm and kinetic models revealed that the adsorption of the dyes onto CPML nanocomposite (NC) was correlated with the Langmuir and pseudo-second-order kinetic model, which indicated a monolayer adsorption manner on the homogeneous surface of NCs. The reusability experiment clarified that the CPML NC could be applied multiple times. Experimental results show that the CPML NC has sufficient potential for treating cationic and anionic dye-contaminated water.


Assuntos
Quitosana , Poluentes Químicos da Água , Corantes/química , Quitosana/química , Poluentes Químicos da Água/química , Cátions/química , Água , Adsorção , Cinética , Azul de Metileno/química , Concentração de Íons de Hidrogênio
9.
J Clin Exp Dent ; 14(11): e903-e910, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36458035

RESUMO

Background: This study aimed to evaluate the remineralization potential and bioactivity of adhesives, containing amorphous calcium phosphate (ACP) and calcium silicate (CS) nanoparticles (NPs). Material and Methods: In this study, dentin slices (n=60) were prepared and etched with phosphoric acid. Next, they were divided into two groups: pre- and post-immersion in a simulated body fluid (SBF) for three weeks. The two groups were also divided into five subgroups (n=6 per subgroup), including the control (0 wt.% NPs); adhesives containing 1 wt.% and 2.5 wt.% (CS) nanoparticles; and adhesives containing 1 wt.% and 2.5 wt.% ACP nanoparticles. The remineralization potential and bioactivity of the adhesives were evaluated. The shear bond strength of the samples (n=18) was also assessed using a universal testing machine. Results: The present results revealed that the adhesive containing ACP and CS nanoparticles showed bioactivity and remineralization potential without any reduction in the bond strength. Conclusions: The outcomes revealed that Cs and ACP nanoparticles induced mineralization in the dentin and incorporation of these nanoparticles to dentin bonding agents could improve the bio-functionalization of dentin bond. Key words:Calcium phosphate, calcium silicate, fourier transform infrared spectroscopy, scanning electron microscopy, tooth remineralization.

10.
Int J Biol Macromol ; 219: 1319-1336, 2022 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-36055598

RESUMO

Bone tissue engineering is a field to manufacture scaffolds for bone defects that cannot repair without medical interventions. Ceramic nanoparticles such as bredigite have importance roles in bone regeneration. We synthesized a novel strontium (Sr) doped bredigite (Bre) nanoparticles (BreSr) and then developed new nanocomposite scaffolds using polycaprolactone (PCL), poly lactic acid (PLA) by the 3D-printing technique. Novel functional nanoparticles were synthesized and characterized using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS: map). The nanoparticles were uniformly distributed in the polymer matrix composites. The 3D- printed scaffolds were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), attenuated total reflection-fourier transform infrared (ATR-FTIR), degradation rate porosity, mechanical tests, apatite formation and cell culture. Degradation rate and mechanical strength were increased in the PLA/PCL/Bre-5%Sr nanocopmposite scaffolds. Hydroxyapatite crystals were also created on the scaffold surface in the bioactivity test. The scaffolds supported viability and proliferation of human osteoblasts. Gene expression and calcium deposition in the samples containing nanoparticles indicated statistical different than the scaffolds without nanoparticles. The nanocomposite scaffolds were implanted into the critical-sized calvarial defects in rat for 3 months. The scaffolds containing Bre-Sr ceramic nanoparticles exhibited the best potential to regenerate bone tissue.


Assuntos
Nanopartículas , Estrôncio , Animais , Apatitas , Amiantos Anfibólicos , Regeneração Óssea , Cálcio , Humanos , Hidroxiapatitas , Ácido Láctico , Nanopartículas/química , Poliésteres/química , Porosidade , Impressão Tridimensional , Ratos , Estrôncio/química , Estrôncio/farmacologia , Engenharia Tecidual/métodos , Alicerces Teciduais/química
11.
Int J Biol Macromol ; 221: 1325-1334, 2022 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-36087749

RESUMO

One of the challenges in critical size bone defect repairing is the use of a porous degradable scaffold with appropriate properties to the host tissue. Nowadays, the three-dimensional (3D) printing method can produce custom and personalized scaffolds and overcome the problems of traditional methods by controlling the porosity and dimensions of biomaterial scaffolds. In this study, polylactic acid/polyethylene glycol (PLA/PEG) scaffolds were prepared with different PEG percentages (0, 5, 10, 15 and 20 wt%) by fused deposition modeling (FDM) to optimize printability and achieve suitable physico-mechanical properties and also enhance cellular behavior for bone tissue engineering and actually, this study complements previous studies. Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) were employed for chemical, morphological and thermal evaluations, respectively. It was shown that the adding of 20 wt% PEG to PLA 3D printed scaffolds reduced water contact angle (from 78.16 ± 3.27 to 60.00 ± 2.16), and increased surface wettability. The results also showed that the mechanical properties of the printed scaffolds were not significantly reduced by adding 5 and 10 wt% of PEG. The addition of PEG increased the degradability of scaffolds during immersion in phosphate buffer saline (PBS) solution for 8 weeks and PLA/PEG20 scaffold with 50.96 % had the highest rate of degradation. MTT assay showed that none of the studied scaffolds had cytotoxicity against MG-63 cells and increasing the PEG levels to 20 wt%, increased cell viability and adhesion and osteogenic differentiation. According to the obtained physical, mechanical and biological results, PLA/PEG scaffold printed by the FDM method can be an appropriate candidate for use in bone repair applications.


Assuntos
Polietilenoglicóis , Engenharia Tecidual , Engenharia Tecidual/métodos , Polietilenoglicóis/química , Osteogênese , Alicerces Teciduais/química , Poliésteres/química , Porosidade , Impressão Tridimensional , Ácido Láctico/química
12.
J Mech Behav Biomed Mater ; 132: 105271, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35623107

RESUMO

The human's heart cannot regenerate after a wound by itself. So myocardial tissue can be damaged, leading to acute inflammation and scar. To overcome this issue, three dimensional (3D) scaffolds with appropriate properties have been proposed. In this study, Poly ε-caprolactone (PCL)/Gold nanoparticles (GNPs) nanocomposite scaffolds containing 0, 0.25 and 0.5 wt% GNPs were prepared by 3-D printing by using Fused Deposition Modeling (FDM) technique. Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Fourier transform-infrared spectroscopy (FTIR-ATR), and X-ray diffraction (XRD) were then used to characterize the scaffolds. Also, mechanical properties, electrical conductivity, contact angle, and thermal behavior of the scaffolds were measured. According to the results, the scaffold containing 0.5 wt% GNPs corroborated optimal properties including appropriate mechanical properties, adequate wettability and suitable electrical conductivity for cardiovascular application, as compressive strength and electrical conductivity were increased approximately by 9.1% and 25%, respectively. In contrast, contact angle was decreased about 38%, which caused the scaffolds' hydrophilicity. Overall the electrocunductive 3D PCL/GNPs 0.5 wt% scaffold could be developed with the control of some parameters that could be well implemented by this fabrication method; also, the addition of GNPs to improve some properties can be regarded as a promising candidate for myocardial tissue engineering.


Assuntos
Nanopartículas Metálicas , Nanocompostos , Condutividade Elétrica , Ouro , Humanos , Nanocompostos/química , Poliésteres/química , Impressão Tridimensional , Engenharia Tecidual/métodos , Alicerces Teciduais/química
13.
J Biomed Mater Res B Appl Biomater ; 110(8): 1814-1826, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35195946

RESUMO

Chronic wounds are among the most therapeutically challenging conditions, which are commonly followed by bacterial infection. The ideal approach to treat such injuries are synergistic infection therapy and skin tissue regeneration. In the recent decades, nanotechnology has played a critical role in eradicating bacterial infections by introducing several carriers developed for drug delivery. Moreover, advances in tissue engineering have resulted in new drug delivery systems that can improve the skin regeneration rate and quality. In this study, cefazolin-loaded niosomes were electrosprayed onto chitosan membrane for wound healing applications. For this purpose, niosomes were obtained by the thin-film hydration method; electrospinning was then conducted to fabricate nanofibrous mats. In vitro characterization of the scaffold was performed to evaluate the physicochemical and biological properties. Finally, in vivo studies were carried out to evaluate the potential use of the membrane for skin regeneration. In vitro results indicated the antibacterial properties of the membrane against Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) due to the gradual release of cefazolin from niosomes. The scaffolds also showed no cell toxicity. In vivo studies also confirmed the ability of the membrane to enhance skin regeneration by improving re-epithelialization, tissue remodeling, and angiogenesis. The current study could well show the promising role of the prepared scaffold for skin regeneration and bacterial infection elimination.


Assuntos
Quitosana , Nanofibras , Antibacterianos/química , Cefazolina/farmacologia , Quitosana/química , Quitosana/farmacologia , Lipossomos/farmacologia , Nanofibras/química , Pseudomonas aeruginosa , Staphylococcus aureus , Cicatrização
14.
Int J Biol Macromol ; 192: 298-322, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34634326

RESUMO

Today, chronic wound care and management can be regarded as a clinically critical issue. However, the limitations of current approaches for wound healing have encouraged researchers and physicians to develop more efficient alternative approaches. Advances in tissue engineering and regenerative medicine have resulted in the development of promising approaches that can accelerate wound healing and improve the skin regeneration rate and quality. The design and fabrication of scaffolds that can address the multifactorial nature of chronic wound occurrence and provide support for the healing process can be considered an important area requiring improvement. In this regard, polysaccharide-based scaffolds have distinctive properties such as biocompatibility, biodegradability, high water retention capacity and nontoxicity, making them ideal for wound healing applications. Their tunable structure and networked morphology could facilitate a number of functions, such as controlling their diffusion, maintaining wound moisture, absorbing a large amount of exudates and facilitating gas exchange. In this review, the wound healing process and the influential factors, structure and properties of carbohydrate polymers, physical and chemical crosslinking of polysaccharides, scaffold fabrication techniques, and the use of polysaccharide-based scaffolds in skin tissue engineering and wound healing applications are discussed.


Assuntos
Materiais Biocompatíveis/química , Polissacarídeos/química , Engenharia Tecidual , Cicatrização , Animais , Ânions/química , Materiais Biocompatíveis/análise , Biomarcadores/química , Biopolímeros/química , Cátions/química , Fenômenos Químicos , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/química , Peptídeos e Proteínas de Sinalização Intercelular/farmacologia , Polissacarídeos/análise , Medicina Regenerativa/métodos , Pele , Engenharia Tecidual/métodos , Alicerces Teciduais/química
15.
Dent Mater J ; 40(4): 870-876, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-33692225

RESUMO

Yttria doped ZrO2 was deposited using an acidic zinc phosphatizing solution and the hydrothermal treatment. The coating was analyzed using a field emission-scanning electron microscope (FE-SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). A piston on three balls (ISO 6872) was used for the measurement of biaxial flexural strength. MC3T3-E1 cells attachment was evaluated by SEM, and cell proliferation were assessed using MTS assay™. SEM images confirmed that the zinc phosphate coating layer was successfully prepared and fully covered the surface. The measured adhesive strength of the coating was 79.11 MPa. In vitro cell study indicated that the coated sample had better cell morphology and proliferation. XRD and EDS analysis revealed that the crystalline coating structure indexed as zinc phosphate (hopeite) and the substrate was assigned as zirconia. The flexural strength test showed that the strength of zirconia before and after hydrothermal treatment was not affected.


Assuntos
Zinco , Zircônio , Teste de Materiais , Propriedades de Superfície , Difração de Raios X
16.
Int Orthod ; 19(2): 259-268, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33775598

RESUMO

OBJECTIVE: To evaluate the effects of remineralizing agents on the shear bond strength (SBS) of orthodontic brackets bonded to intact and demineralized enamel. MATERIAL AND METHODS: In this in-vitro study, 160 human premolars were divided into 8 groups, including group 1 with intact enamel as the positive control, group 2 with demineralized enamel as the negative control, groups 3-5 treated with fluoride varnish, Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP) and resin infiltrant on intact enamel, and groups 6-8 treated with the same agents on demineralized enamel. Brackets were bonded using the conventional method, and the samples were thermocycled. SBS of the brackets was measured using a universal testing machine, and the adhesive remnant index (ARI) was assessed. Data were analysed with one-way ANOVA and post hoc statistical test at the significance level of 0.05. RESULTS: SBS of the brackets in all groups with intact enamel was higher than that of their counterparts on demineralized enamel, which was only significantly different between groups 1 and 2 (P-value<0.001). SBS values of groups 7 and 8 were not significantly different from group 1 (P-value=1), yet the application of fluoride varnish on both intact (P-value=0.091) and demineralized enamel (P-value<0.001) created less SBS than in group 1. CONCLUSIONS: All pre-treatment methods increased SBS of the brackets bonded to demineralized enamel, yet only the resin infiltrant and CPP-ACP produced SBS similar to that of intact enamel. Also, the use of fluoride varnish on intact enamel significantly reduced SBS.


Assuntos
Colagem Dentária , Braquetes Ortodônticos , Fosfatos de Cálcio , Caseínas , Esmalte Dentário , Fluoretos , Fluoretos Tópicos , Humanos , Teste de Materiais , Fosfopeptídeos , Cimentos de Resina , Resistência ao Cisalhamento
17.
Artigo em Inglês | MEDLINE | ID: mdl-33455539

RESUMO

In this work the binding of artificial sweetener aspartame with human serum albumin (HSA) was studied at physiological pH. Binding studies of aspartame (APM) with HSA are useful to understand APM -HSA interaction, mechanism and providing guidance for the application and design of new and more efficient artificial sweeteners. The interaction was investigated by spectrophotometric, spectrofluorometric competition experiment and circular dichroism (CD) techniques. The results indicated that the binding of APM to HSA caused fluorescence quenching of HSA through static quenching mechanism with binding constant 1.42 × 10+4 M-1 at 298 K and the number of binding sites is approximately one. Thermodynamic parameters, enthalpy changes (ΔH) and entropy changes (ΔS) were calculated to be -41.20 kJ mol-1 and -58.19 J mol-1 K-1, respectively, according to van't Hoff equation, which indicated that reaction is enthalpically driven. Quenching of the fluorescence of HSA was found to be a static quenching process. The binding constants and number of binding sites were obtained at three different temperatures (298, 308 and 318 K). Combining above results and those of spectrofluorometric competition experiment and circular dichroism (CD), indicated that APM binds to HSA via Sudlow's site I. Furthermore, the study of molecular docking on HSA binding also indicated that APM can strongly bind to the site I (subdomain IIA) of HSA mainly by hydrophobic interaction and hydrogen bond interactions exist between APM and HSA.


Assuntos
Aspartame/metabolismo , Albumina Sérica Humana/metabolismo , Análise Espectral , Ligação Competitiva , Humanos , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Albumina Sérica Humana/química
18.
J Nanobiotechnology ; 19(1): 1, 2021 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-33397416

RESUMO

Skin is the body's first barrier against external pathogens that maintains the homeostasis of the body. Any serious damage to the skin could have an impact on human health and quality of life. Tissue engineering aims to improve the quality of damaged tissue regeneration. One of the most effective treatments for skin tissue regeneration is to improve angiogenesis during the healing period. Over the last decade, there has been an impressive growth of new potential applications for nanobiomaterials in tissue engineering. Various approaches have been developed to improve the rate and quality of the healing process using angiogenic nanomaterials. In this review, we focused on molecular mechanisms and key factors in angiogenesis, the role of nanobiomaterials in angiogenesis, and scaffold-based tissue engineering approaches for accelerated wound healing based on improved angiogenesis.


Assuntos
Nanocompostos , Alicerces Teciduais , Cicatrização , Indutores da Angiogênese , Angiopoietinas/metabolismo , Animais , Vasos Sanguíneos , Humanos , Qualidade de Vida , Pele , Engenharia Tecidual , Fator A de Crescimento do Endotélio Vascular
19.
Tissue Cell ; 68: 101470, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33248403

RESUMO

Any significant loss of vision or blindness caused by corneal damages is referred to as corneal blindness. Corneal blindness is the fourth most common cause of blindness worldwide, representing more than 5% of the total blind population. Currently, corneal transplantation is used to treat many corneal diseases. In some cases, implantation of artificial cornea (keratoprosthesis) is suggested after a patient has had a donor corneal transplant failure. The shortage of donors and the side effects of keratoprosthesis are limiting these approaches. Recently, researchers have been actively pursuing new approaches for corneal regeneration because of these limitations. Nowadays, tissue engineering of different corneal layers (epithelium, stroma, endothelium, or full thickness tissue) is a promising approach that has attracted a great deal of interest from researchers and focuses on regenerative strategies using different cell sources and biomaterials. Various sources of corneal and non-corneal stem cells have shown significant advantages for corneal epithelium regeneration applications. Pluripotent stem cells (embryonic stem cells and iPS cells), epithelial stem cells (derived from oral mucus, amniotic membrane, epidermis and hair follicle), mesenchymal stem cells (bone marrow, adipose-derived, amniotic membrane, placenta, umbilical cord), and neural crest origin stem cells (dental pulp stem cells) are the most promising sources in this regard. These cells could also be used in combination with natural or synthetic scaffolds to improve the efficacy of the therapeutic approach. As the ocular surface is exposed to external damage, the number of studies on regeneration of the corneal epithelium is rising. In this paper, we reviewed the stem cell-based strategies for corneal epithelium regeneration.


Assuntos
Epitélio Corneano/fisiopatologia , Regeneração/fisiologia , Transplante de Células-Tronco , Animais , Ensaios Clínicos como Assunto , Humanos , Células-Tronco/citologia , Engenharia Tecidual
20.
J Tissue Eng Regen Med ; 15(2): 116-128, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33175476

RESUMO

The aim of this study was evaluating the effects of vacuum on microstructure and biocompatibility of bovine decellularized pericardium. So the bovine pericardia were decellularized and then the vacuum was applied for two periods of time; 90 and 180 min. DNA, glucose amino glycan, collagen and elastin content assay, scanning electron microscopy (SEM) examination, hematoxylin and eosin (H&E) and Masson's trichrome stainings performed to evaluate microstructure of tissues. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test, subcutaneous implantation, and tensile test were used to assay biocompatibility and mechanical properties of decellularized tissues. The results showed that applying vacuum reduced residual DNA significantly. Vacuum after 180 min reduced more residual DNA. There were no significant differences in the content of glucose amino glycan (GAG), collagen, and elastin between the vacuumed and control groups. SEM examination was revealed that vacuum for 180 min increased pore size and porosity more than 90 min and control groups. H&E and Masson's trichrome stainings revealed extracellular matrix preservation after decellularization in all groups. Cell viability was increased in vacuumed samples significantly after 72 h in vaccumed samples. H&E staining and tensile test after implantation of tissues were showed less inflammation in the vacuum applied tissues and increased durability. The vacuum increased DNA removal, pore size, porosity, and biocompatibility in vitro and in vivo and durability of bovine decellularized pericardium in vivo. Considering the important role of time, more studies should be performed to optimize time, intensity, and method of application of vacuum in decellularization of different tissues as well as bovine pericardium.


Assuntos
Matriz Extracelular/química , Teste de Materiais , Células-Tronco Mesenquimais/metabolismo , Pericárdio/química , Engenharia Tecidual , Alicerces Teciduais/química , Animais , Bovinos , Técnicas de Cultura de Células , Humanos , Vácuo
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