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1.
Mater Sci Eng C Mater Biol Appl ; 127: 112196, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34225849

RESUMO

Textile engineering can offer a multi-scale toolbox via various fiber or textile fabrication methods to obtain woven or nonwoven aerogels with different structural and mechanical properties to overcome the current limitations of polysaccharide-based aerogels, such as poor mechanical properties and undeveloped shaping techniques. Hereby, a high viscous solution of microcrystalline cellulose and zinc chloride hydrate was wet spun to produce mono and multi-filament alcogel microfibers. Subsequently, cellulose aerogel fibers (CAF) were produced and impregnated with model drugs using supercritical CO2 processes. Fibers were characterized in terms of morphology and textural properties, thermal stability, mechanical properties, and in vitro biological and drug release assessments. Loaded and non-loaded CAFs proved to have a macro-porous outer shell and a nano-porous inner core with interconnected pore structure and a specific area in the range of 100-180 m2/g. The CAFs with larger diameter (d ~ 235 µm) were able to form knitted mesh while lower diameter fibers (d ~ 70 µm) formed needle punched nonwoven textiles. Humidity and water uptake assessments indicated that the fibrous structures were highly moisture absorbable and non-toxic with immediate drug release profiles due to the highly open interconnected porous structure of the fibers. Finally, CAFs are propitious to be further developed for biomedical applications such as drug delivery and wound care.


Assuntos
Celulose , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Géis , Porosidade
2.
Int J Mol Sci ; 22(12)2021 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-34199292

RESUMO

Giant unilamellar vesicles (GUV) are powerful tools to explore physics and biochemistry of the cell membrane in controlled conditions. For example, GUVs were extensively used to probe cell adhesion, but often using non-physiological linkers, due to the difficulty of incorporating transmembrane adhesion proteins into model membranes. Here we describe a new protocol for making GUVs incorporating the transmembrane protein integrin using gel-assisted swelling. We report an optimised protocol, enumerating the pitfalls encountered and precautions to be taken to maintain the robustness of the protocol. We characterise intermediate steps of small proteoliposome formation and the final formed GUVs. We show that the integrin molecules are successfully incorporated and are functional.


Assuntos
Géis/química , Integrinas/metabolismo , Lipossomas Unilamelares/química , Adesão Celular , Fluorescência , Humanos , Bicamadas Lipídicas/metabolismo , Lipídeos/química , Tamanho da Partícula
3.
Molecules ; 26(11)2021 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-34204905

RESUMO

Cyclodipeptides (CDPs) or 2,5-diketopiperazines (DKPs) can exert a variety of biological activities and display pronounced resistance against enzymatic hydrolysis as well as a propensity towards self-assembly into gels, relative to the linear-dipeptide counterparts. They have attracted great interest in a variety of fields spanning from functional materials to drug discovery. This concise review will analyze the latest advancements in their synthesis, self-assembly into gels, and their more innovative applications.


Assuntos
Dicetopiperazinas/síntese química , Dipeptídeos/química , Peptídeos Cíclicos/síntese química , Dicetopiperazinas/química , Géis/química , Química Verde , Micro-Ondas , Estrutura Molecular , Peptídeos Cíclicos/química
4.
Molecules ; 26(11)2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-34200144

RESUMO

Natural products have been extensively used for treating a wide variety of disorders. In recent times, Brucine (BRU) as one of the natural medications extracted from seeds of nux vomica, was investigated for its anticancer activity. As far as we know, this is the first study on BRU anticancer activity against skin cancer. Thus, the rational of this work was implemented to develop, optimize and characterize the anticancer activity of BRU loaded ethosomal gel. Basically, thin film hydration method was used to formulate BRU ethosomal preparations, by means of Central composite design (CCD), which were operated to construct (32) factorial design. Two independent variables were designated (phospholipid percentage and ethanol percentage) with three responses (vesicular size, encapsulation efficiency and flux). Based on the desirability function, one formula was selected and incorporated into HPMC gel base to develop BRU loaded ethosomal gel. The fabricated gel was assessed for all physical characterization. In-vitro release investigation, ex-vivo permeation and MTT calorimetric assay were performed. BRU loaded ethosomal gel exhibited acceptable values for the characterization parameters which stand proper for topical application. In-vitro release investigation was efficiently prolonged for 6 h. The flux from BRU loaded ethosome was enhanced screening optimum SSTF value. Finally, in-vitro cytotoxicity study proved that BRU loaded ethosomal gel significantly improved the anticancer activity of the drug against A375 human melanoma cell lines. Substantially, the investigation proposed a strong motivation for further study of the lately developed BRU loaded ethosomal gel as a prospective therapeutic strategy for melanoma treatment.


Assuntos
Etanol/química , Géis/química , Pele/efeitos dos fármacos , Estricnina/análogos & derivados , Administração Cutânea , Animais , Géis/administração & dosagem , Masculino , Fosfolipídeos/química , Ratos , Ratos Wistar , Absorção Cutânea/efeitos dos fármacos , Neoplasias Cutâneas/tratamento farmacológico , Estricnina/administração & dosagem , Estricnina/química
5.
Molecules ; 26(12)2021 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-34200653

RESUMO

Cushioning and antibacterial packaging are the requirements of the storage and transportation of fruits and vegetables, which are essential for reducing the irreversible quality loss during the process. Herein, the composite of carboxymethyl nanocellulose, glycerin, and acrylamide derivatives acted as the shell and chitosan/AgNPs were immobilized in the core by using coaxial 3D-printing technology. Thus, the 3D-printed cushioning-antibacterial dual-function packaging aerogel with a shell-core structure (CNGA/C-AgNPs) was obtained. The CNGA/C-AgNPs packaging aerogel had good cushioning and resilience performance, and the average compression resilience rate was more than 90%. Although AgNPs was slowly released, CNGA/C-AgNPs packaging aerogel had an obvious antibacterial effect on E. coli and S. aureus. Moreover, the CNGA/C-AgNPs packaging aerogel was biodegradable. Due to the customization capabilities of 3D-printing technology, the prepared packaging aerogel can be adapted to more application scenarios by accurately designing and regulating the microstructure of aerogels, which provides a new idea for the development of food intelligent packaging.


Assuntos
Antibacterianos/química , Celulose/química , Embalagem de Alimentos/métodos , Géis/química , Nanopartículas Metálicas/química , Antibacterianos/farmacologia , Quitosana/química , Escherichia coli/efeitos dos fármacos , Impressão Tridimensional , Prata/química , Staphylococcus aureus/efeitos dos fármacos
6.
Molecules ; 26(12)2021 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-34200887

RESUMO

Royal jelly is a natural substance produced by worker bees that possesses a variety of biological activities, including antioxidant, anti-inflammatory, antibacterial, and protective. Although fresh royal jelly is kept at low temperatures, to increase its stability, it needs to be incorporated into pharmaceutical formulations, such as in situ gels. The aim of this study was to formulate in situ ocular gels containing Lithuanian royal jelly for topical corneal use in order to increase the retention time of the formulation on the ocular surface and bioavailability. Gels were evaluated for physicochemical characteristics (pH, rheological properties, refractive index) and in vitro drug release measuring the amount of 10-hydroxy-2-decenoic acid (10-HDA). An ocular irritation test and cell viability tests were performed using the SIRC (Statens Seruminstitut Rabbit Cornea) cell culture line. Results indicated that all the in situ gels were within an acceptable pH and refractive index range close to corneal properties. Rheology studies have shown that the gelation temperature varies between 25 and 32 °C, depending on the amount of poloxamers. The release studies have shown that the release of 10-HDA from in situ gels is more sustained than royal jelly suspension. All gel formulations were non-irritant according to the short-time exposure test (STE) using the SIRC cell culture line, and long-term cell viability studies indicated that the formulations used in small concentrations did not induce cell death. Prepared in situ gels containing royal jelly have potential for ocular drug delivery, and they may improve the bioavailability, stability of royal jelly, and formation of non-irritant ocular formulations.


Assuntos
Córnea/efeitos dos fármacos , Ácidos Graxos/química , Ácidos Graxos/farmacologia , Géis/química , Géis/farmacologia , Animais , Abelhas/metabolismo , Disponibilidade Biológica , Produtos Biológicos/química , Produtos Biológicos/farmacocinética , Produtos Biológicos/farmacologia , Morte Celular/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Química Farmacêutica/métodos , Córnea/metabolismo , Ácidos Decanoicos/química , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacocinética , Preparações de Ação Retardada/farmacologia , Sistemas de Liberação de Medicamentos/métodos , Liberação Controlada de Fármacos/efeitos dos fármacos , Excipientes/química , Géis/farmacocinética , Poloxâmero/química , Coelhos , Reologia , Temperatura
7.
Cochrane Database Syst Rev ; 5: CD013621, 2021 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-34097765

RESUMO

BACKGROUND: Pressure ulcers (also known as pressure injuries) are localised injuries to the skin or underlying soft tissue, or both, caused by unrelieved pressure, shear or friction. Foam surfaces (beds, mattresses or overlays) are widely used with the aim of preventing pressure ulcers. OBJECTIVES: To assess the effects of foam beds, mattresses or overlays compared with any support surface on the incidence of pressure ulcers in any population in any setting. SEARCH METHODS: In November 2019, we searched the Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE (including In-Process & Other Non-Indexed Citations); Ovid Embase and EBSCO CINAHL Plus. We also searched clinical trials registries for ongoing and unpublished studies, and scanned reference lists of relevant included studies as well as reviews, meta-analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting. SELECTION CRITERIA: We included randomised controlled trials that allocated participants of any age to foam beds, mattresses or overlays. Comparators were any beds, mattresses or overlays. DATA COLLECTION AND ANALYSIS: At least two review authors independently assessed studies using predetermined inclusion criteria. We carried out data extraction, 'Risk of bias' assessment using the Cochrane 'Risk of bias' tool, and the certainty of the evidence assessment according to Grading of Recommendations, Assessment, Development and Evaluations methodology. If a foam surface was compared with surfaces that were not clearly specified, then the included study was recorded and described but not considered further in any data analyses. MAIN RESULTS: We included 29 studies (9566 participants) in the review. Most studies were small (median study sample size: 101 participants). The average age of participants ranged from 47.0 to 85.3 years (median: 76.0 years). Participants were mainly from acute care settings. We analysed data for seven comparisons in the review: foam surfaces compared with: (1) alternating pressure air surfaces, (2) reactive air surfaces, (3) reactive fibre surfaces, (4) reactive gel surfaces, (5) reactive foam and gel surfaces, (6) reactive water surfaces, and (7) another type of foam surface. Of the 29 included studies, 17 (58.6%) presented findings which were considered at high overall risk of bias. PRIMARY OUTCOME: pressure ulcer incidence Low-certainty evidence suggests that foam surfaces may increase the risk of developing new pressure ulcers compared with (1) alternating pressure (active) air surfaces (risk ratio (RR) 1.59, 95% confidence interval (CI) 0.86 to 2.95; I2 = 63%; 4 studies, 2247 participants), and (2) reactive air surfaces (RR 2.40, 95% CI 1.04 to 5.54; I2 = 25%; 4 studies, 229 participants). We are uncertain regarding the difference in pressure ulcer incidence in people treated with foam surfaces and the following surfaces: (1) reactive fibre surfaces (1 study, 68 participants); (2) reactive gel surfaces (1 study, 135 participants); (3) reactive gel and foam surfaces (1 study, 91 participants); and (4) another type of foam surface (6 studies, 733 participants). These had very low-certainty evidence. Included studies have data on time to pressure ulcer development for two comparisons. When time to ulcer development is considered using hazard ratios, the difference in the risk of having new pressure ulcers, over 90 days' follow-up, between foam surfaces and alternating pressure air surfaces is uncertain (2 studies, 2105 participants; very low-certainty evidence). Two further studies comparing different types of foam surfaces also reported time-to-event data, suggesting that viscoelastic foam surfaces with a density of 40 to 60 kg/m3 may decrease the risk of having new pressure ulcers over 11.5 days' follow-up compared with foam surfaces with a density of 33 kg/m3 (1 study, 62 participants); and solid foam surfaces may decrease the risk of having new pressure ulcers over one month's follow-up compared with convoluted foam surfaces (1 study, 84 participants). Both had low-certainty evidence. There was no analysable data for the comparison of foam surfaces with reactive water surfaces (one study with 117 participants). Secondary outcomes Support-surface-associated patient comfort: the review contains data for three comparisons for this outcome. It is uncertain if there is a difference in patient comfort measure between foam surfaces and alternating pressure air surfaces (1 study, 76 participants; very low-certainty evidence); foam surfaces and reactive air surfaces (1 study, 72 participants; very low-certainty evidence); and different types of foam surfaces (4 studies, 669 participants; very low-certainty evidence). All reported adverse events: the review contains data for two comparisons for this outcome. We are uncertain about differences in adverse effects between foam surfaces and alternating pressure (active) air surfaces (3 studies, 2181 participants; very low-certainty evidence), and between foam surfaces and reactive air surfaces (1 study, 72 participants; very low-certainty evidence). Health-related quality of life: only one study reported data on this outcome. It is uncertain if there is a difference (low-certainty evidence) between foam surfaces and alternating pressure (active) air surfaces in health-related quality of life measured with two different questionnaires, the EQ-5D-5L (267 participants) and the PU-QoL-UI (233 participants). Cost-effectiveness: one study reported trial-based cost-effectiveness evaluations. Alternating pressure (active) air surfaces are probably more cost-effective than foam surfaces in preventing pressure ulcer incidence (2029 participants; moderate-certainty evidence). AUTHORS' CONCLUSIONS: Current evidence suggests uncertainty about the differences in pressure ulcer incidence, patient comfort, adverse events and health-related quality of life between using foam surfaces and other surfaces (reactive fibre surfaces, reactive gel surfaces, reactive foam and gel surfaces, or reactive water surfaces). Foam surfaces may increase pressure ulcer incidence compared with alternating pressure (active) air surfaces and reactive air surfaces. Alternating pressure (active) air surfaces are probably more cost-effective than foam surfaces in preventing new pressure ulcers. Future research in this area should consider evaluation of the most important support surfaces from the perspective of decision-makers. Time-to-event outcomes, careful assessment of adverse events and trial-level cost-effectiveness evaluation should be considered in future studies. Trials should be designed to minimise the risk of detection bias; for example, by using digital photography and by blinding adjudicators of the photographs to group allocation. Further review using network meta-analysis will add to the findings reported here.


Assuntos
Roupas de Cama, Mesa e Banho , Leitos , Lesão por Pressão/prevenção & controle , Substâncias Viscoelásticas , Idoso , Idoso de 80 Anos ou mais , Ar , Viés , Feminino , Géis , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Lesão por Pressão/epidemiologia , Ensaios Clínicos Controlados Aleatórios como Assunto
8.
Int J Nanomedicine ; 16: 3725-3739, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34103913

RESUMO

Purpose: Transarterial chemoembolization is the preferred treatment for patients with middle and advanced-stage hepatocellular carcinoma (HCC); however, most hepatic artery embolization agents have various disadvantages. The purpose of this study was to evaluate phytantriol-based liquid crystal injections for potential use in treatment of HCC. Methods: Using sinomenine (SN) and 5-fluorouracil (5-FU) as model drugs, three precursor in situ liquid crystal injections based on phytantriol (P1, P2, and P3) were prepared, and their in vitro biocompatibility, anticancer activity, and drug release investigated, to evaluate their feasibility for use in treatment of HCC. The properties of the precursor injections and subsequent cubic liquid crystal gels were observed by visual and polarizing microscopy, in an in vitro gelation experiment. Biocompatibility was evaluated by in vitro hemolysis, histocompatibility, and cytotoxicity assays. Results: Precursor injections were colorless liquids that formed transparent cubic liquid crystal gels on addition of excess water. The three precursor injections all caused slight hemolysis, without agglutination, and were mildly cytotoxic. Histocompatibility experiments showed that P1 had good histocompatibility, while P2 and P3 resulted in strong inflammatory responses, which subsequently resolved spontaneously. In vitro anti-cancer testing showed that SN and 5-FU inhibited HepG2 cells in a time- and concentration-dependent manner and had synergistic effects. Further, in vitro release assays indicated that all three preparations had sustained release effects, with cumulative release of >80% within 48 h. Conclusion: These results indicate that SN and 5-FU have synergistic inhibitory effects on HepG2 cells, which has not previously been reported. Moreover, we describe a biocompatible precursor injection, useful as a drug carrier for the treatment of liver cancer, which can achieve targeting, sustained release, synergistic chemotherapy, and embolization. These data indicate that precursor injections containing SN and 5-FU have great potential for use in therapy for liver cancer.


Assuntos
Fluoruracila/uso terapêutico , Cristais Líquidos/química , Neoplasias Hepáticas/tratamento farmacológico , Morfinanos/uso terapêutico , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Carcinoma Hepatocelular/tratamento farmacológico , Morte Celular , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Sinergismo Farmacológico , Álcoois Graxos/química , Fluoruracila/farmacologia , Géis , Hemólise , Células Hep G2 , Humanos , Injeções , Morfinanos/farmacologia , Ratos Sprague-Dawley , Água/química
9.
Food Chem ; 361: 130075, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34077880

RESUMO

The impact of ozone-induced oxidation on the gel properties of egg yolk was investigated for the first time in this research. The textural properties, water-holding capacity, cooking loss rate and color of the chicken egg yolk gel (CEYG) were significantly improved after ozonation. The maximum hardness value (976.04 g) was reached at 20 min of ozonation and it was 134.92 g higher than that of the natural group. Additionally, the ozone-treated yolk showed an increase of 58.47% in carbonyl content and a decrease of 44.33% in free sulfhydryl groups. The results of low-field nuclear magnetic resonance indicated that ozone promoted the conversion of free water to non-flowing water in the CEYG. Scanning electron microscopy represented that the moderate ozone treatment resulted in a more regular, continuous and smooth network structure of the CEYG. These results provided a theoretical basis for the application of ozone to improve the performance of heat-induced CEYG.


Assuntos
Gema de Ovo/química , Ozônio/química , Água/química , Animais , Galinhas , Géis/química , Dureza , Oxirredução , Reologia
10.
Molecules ; 26(9)2021 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-34066568

RESUMO

Periodontal diseases are worldwide health problems that negatively affect the lifestyle of many people. The long-term effect of the classical treatments, including the mechanical removal of bacterial plaque, is not effective enough, causing the scientific world to find other alternatives. Polymer-drug systems, which have different forms of presentation, chosen depending on the nature of the disease, the mode of administration, the type of polymer used, etc., have become very promising. Hydrogels, for example (in the form of films, micro-/nanoparticles, implants, inserts, etc.), contain the drug included, encapsulated, or adsorbed on the surface. Biologically active compounds can also be associated directly with the polymer chains by covalent or ionic binding (polymer-drug conjugates). Not just any polymer can be used as a support for drug combination due to the constraints imposed by the fact that the system works inside the body. Biopolymers, especially polysaccharides and their derivatives and to a lesser extent proteins, are preferred for this purpose. This paper aims to review in detail the biopolymer-drug systems that have emerged in the last decade as alternatives to the classical treatment of periodontal disease.


Assuntos
Sistemas de Liberação de Medicamentos , Periodontite/tratamento farmacológico , Polissacarídeos/química , Animais , Antibacterianos/farmacologia , Anti-Inflamatórios/química , Biopolímeros/química , Celulose/química , Quitosana/química , Reagentes para Ligações Cruzadas/química , Cães , Portadores de Fármacos , Géis , Humanos , Hidrogéis/química , Cinética , Microscopia Eletrônica de Varredura , Nanopartículas/química , Doenças Periodontais/tratamento farmacológico , Ratos
11.
Molecules ; 26(11)2021 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-34073361

RESUMO

CBD is a promising candidate for treatment of many diseases and plays a major role in the growing trend to produce high-end drugs from natural, renewable resources. In the present work, we demonstrate a way to incorporate the anti-inflammatory drug CBD into smart microgel particles. The copolymer microgels that we chose as carrier systems exhibit a volume phase transition temperature of 39 ∘C, which is just above normal body temperature and makes them ideal candidates for hyperthermia treatment. While a simple loading route of CBD was not successful due to the enormous hydrophobicity of CBD, an alternative route was developed by immersing the microgels in ethanol. Despite the expected loss of thermoresponsive behaviour of the microgel matrix due to the solvent exchange, a temperature-dependent release of CBD was detected by the material, creating an interesting question of interactions between CBD and the microgel particles in ethanol. Furthermore, the method developed for loading of the microgel particles with CBD in ethanol was further improved by a subsequent transfer of the loaded particles into water, which proves to be an even more promising approach due to the successful temperature-dependent release of the drug above the collapse temperature of the microgels.


Assuntos
Anti-Inflamatórios/farmacologia , Canabidiol/farmacologia , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Microgéis , Acrilamidas/química , Anti-Inflamatórios/análise , Canabidiol/análise , Etanol , Géis , Espectroscopia de Ressonância Magnética , Microscopia de Força Atômica , Transição de Fase , Fótons , Polímeros/química , Espalhamento de Radiação , Solventes , Espectrofotometria Ultravioleta , Tensoativos , Temperatura
12.
Food Chem ; 362: 130253, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34116429

RESUMO

The effect of high amylose corn starch (HAS)-fatty acid complexes on the gel properties, protein secondary structure, microstructure, fatty acid content, and sensory properties of surimi under high-temperature treatment were investigated. The formation of HAS-fatty acid complexes increased melting temperature and decreased average particle size of HAS. The addition of HAS-fatty acid complexes significantly improved the breaking force, deformation and whiteness of surimi gels. The water in surimi gels containing HAS or HAS-fatty acid complexes became increasingly immobilized. HAS or HAS-fatty acid complexes promoted protein conformational transition from α-helix structure to other three secondary structure. Surimi gels added with HAS-fatty acid complexes had more compact network structure and higher fatty acid content. Moreover, the better sensory properties were obtained in surimi gels containing HAS-fatty acid complexes. Therefore, starch-fatty acid complexes not only could improve the gel properties of surimi, but also enhance its fatty acid content.


Assuntos
Ácidos Graxos/química , Produtos Pesqueiros/análise , Produtos Pesqueiros/normas , Peixes , Aditivos Alimentares/química , Géis/química , Temperatura Alta , Amido/química , Animais , Ácidos Graxos/análise , Proteínas de Peixes/química
13.
Langmuir ; 37(23): 7032-7038, 2021 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-34082534

RESUMO

Mixtures of surfactants, long-chain alcohols, and water sometimes yield lamellar gels with hexagonally packed alkyl chains. This assembly is called "α-gel" or "α-form hydrated crystal." In this study, we characterized the rheological properties of α-gel prepared using disodium N-dodecanoylglutamate (C12Glu-2Na), 1-hexadecanol (C16OH), and water at different NaCl concentrations. The α-gel structure was assessed using small- and wide-angle X-ray scattering (SWAXS). The SWAXS measurements revealed that an increased NaCl concentration (0-200 mmol dm-3) resulted in a decreased d-spacing caused by the screening of electrostatic repulsion between lamellar bilayers. This led to an increased amount of excess water (i.e., the water present between the α-gel domains), and hence, the viscosity of the α-gel decreased in the range of the NaCl concentration. A further increase in the NaCl concentration (200-1000 mmol dm-3) resulted in decreased electrostatic repulsion between the α-gel domains and/or an increased number of α-gel domains (multilamellar vesicles). These effects increased the domain-to-domain interactions, leading to increased viscosity. Therefore, we concluded that the viscosity of the α-gel was controlled by the amount of excess water and the domain-to-domain interactions. Once the network structure collapsed under the strain, it was difficult to recover the original network structure. The low recoverability resulted from increased cohesion between the domains at high NaCl concentrations.


Assuntos
Aminoácidos , Tensoativos , Álcoois , Géis , Reologia , Cloreto de Sódio
14.
Biomacromolecules ; 22(7): 2902-2909, 2021 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-34161074

RESUMO

Strain hardening has recently emerged as a near-universal response of biological tissues to mechanical stimulation as well as a powerful regulator of cell fate. Understanding the mechanistic basis for this nonlinear elasticity is crucial for developing bioinspired materials that mimic extracellular matrix mechanics. Here, we show that covalent networks built from highly acetylated chitosans exhibit strain hardening at physiological pH and osmolarity. While varying the chitosan physical-chemical composition and network connectivity, we provide evidence that temporary nodes arising from the entangling of chains between stable cross-links are at the root of nonlinear elasticity. The contour length (Lc) of the said chains revealed that the larger the chain length between the cross-links, the greater is the entanglement over disentanglement upon network stretching. To this end, we calculated that the minimum number of Khun's segments in Lc that contributes to the onset of strain hardening is 15. Furthermore, we identified a relationship between critical strain marking nonlinear elasticity and the network connectivity, being similar to that found for the cytoskeletal collagen matrix, indicating the potential use of semiflexible (neutral pH-soluble) chitosans in assembling extracellular matrix mimics.


Assuntos
Quitosana , Colágeno , Elasticidade , Matriz Extracelular , Géis , Estresse Mecânico
15.
Langmuir ; 37(26): 7955-7965, 2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34169719

RESUMO

The self-assembly of lipids into nanoscale vesicles (liposomes) is routinely accomplished in water. However, reports of similar vesicles in polar organic solvents like glycerol, formamide, and ethylene glycol (EG) are scarce. Here, we demonstrate the formation of nanoscale vesicles in glycerol, formamide, and EG using the common phospholipid lecithin (derived from soy). The samples we study are simple binary mixtures of lecithin and the solvent, with no additional cosurfactants or salt. Lecithin dissolves readily in the solvents and spontaneously gives rise to viscous fluids at low lipid concentrations (∼2-4%), with structures ∼200 nm detected by dynamic light scattering. At higher concentrations (>10%), lecithin forms clear gels that are strongly birefringent at rest. Dynamic rheology confirms the elastic response of gels, with their elastic modulus being ∼20 Pa at ∼10% lipid. Images from cryo-scanning electron microscopy (cryo-SEM) indicate that concentrated samples are "vesicle gels," where multilamellar vesicles (MLVs, also called "onions"), with diameters between 50 and 600 nm, are close-packed across the sample volume. This structure can explain both the elastic rheology as well as the static birefringence of the samples. The discovery of vesicles and vesicle gels in polar solvents widens the scope of systems that can be created by self-assembly. Interestingly, it is much easier to form vesicles in polar solvents than in water, and the former are stable indefinitely, whereas the latter tend to aggregate or coalesce over time. The stability is attributed to refractive index-matching between lipid bilayers and the solvents, i.e., these vesicles are relatively "invisible" and thus experience only weak attractions. The ability to use lipids (which are "green" or eco-friendly molecules derived from renewable natural sources) to thicken and form gels in polar solvents could also prove useful in a variety of areas, including cosmetics, pharmaceuticals, and lubricants.


Assuntos
Bicamadas Lipídicas , Lipossomos , Géis , Fosfolipídeos , Solventes
16.
Nat Commun ; 12(1): 3961, 2021 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-34172721

RESUMO

Current materials used in biomedical devices do not match tissue's mechanical properties and leach various chemicals into the body. These deficiencies pose significant health risks that are further exacerbated by invasive implantation procedures. Herein, we leverage the brush-like polymer architecture to design and administer minimally invasive injectable elastomers that cure in vivo into leachable-free implants with mechanical properties matching the surrounding tissue. This strategy allows tuning curing time from minutes to hours, which empowers a broad range of biomedical applications from rapid wound sealing to time-intensive reconstructive surgery. These injectable elastomers support in vitro cell proliferation, while also demonstrating in vivo implant integrity with a mild inflammatory response and minimal fibrotic encapsulation.


Assuntos
Materiais Biomiméticos/administração & dosagem , Elastômeros/administração & dosagem , Procedimentos Cirúrgicos Reconstrutivos/métodos , Animais , Materiais Biocompatíveis/administração & dosagem , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Materiais Biomiméticos/química , Materiais Biomiméticos/farmacologia , Proliferação de Células/efeitos dos fármacos , Elastômeros/química , Elastômeros/farmacologia , Géis , Injeções , Camundongos , Polímeros/administração & dosagem , Polímeros/química , Polímeros/farmacologia , Ratos , Fatores de Tempo
17.
J Food Sci ; 86(7): 3061-3074, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34151429

RESUMO

In order to optimize protein recovery from catfish byproducts by alkaline extraction, the effects of different factors, including particle size, mince-to-water ratio, pH, and extraction time were investigated. It was found that a protein recovery of about 30% could be achieved. Increases in pH (pH 10.5, 11, and 11.5) not only improved protein recovery, but also increased protein denaturation evidenced by decreased solubility, decreased α-helix, increased ß-sheet, and increased random coil. The color and texture of gels made from protein isolate were greatly affected by the pH values used for protein extraction. For the gels made from fillet mince, and protein isolates extracted at pH 10.5, 11, and 11.5, the "L" values were 78.96, 60.38, 57.74, and 54.39, the breaking forces were 205, 492, 585, and 458 g, and deformation values were 10.59, 8.07, 6.73, and 5.04 mm, respectively. Electrophoresis revealed protein degradation during alkali-aided extraction with MHC, the most predominant band, showing about 50% decrease in comparison with fillet mince. It also demonstrated that gelation not only caused cross-linking, but also autolysis with 53%, 56%, 59%, and 81% decrease in MHC intensity for fillet mince, protein isolates extracted at pH 10.5, 11, and 11.5, respectively. Fillet mince and protein isolates exhibited different storage modulus patterns during temperature sweep, implying different gelation mechanisms. This study proved the protein extracted from catfish byproducts was potential to be utilized as edible food components especially in gel making. PRACTICAL APPLICATION: Catfish byproducts, which account for 70% of total weight and 50% of total protein of catfish, are normally used as animal feed, fertilizer, or even waste. This study demonstrated the potential of the utilization of catfish wastes to develop edible food components. This could reduce the total processing waste being discarded into the environment and nutrient loss, therefore increasing profitability of catfish industry.


Assuntos
Proteínas de Peixes/farmacologia , Géis/química , Extratos de Tecidos/química , Animais , Peixes-Gato , Proteínas de Peixes/química , Concentração de Íons de Hidrogênio , Solubilidade , Temperatura
18.
BMC Neurol ; 21(1): 242, 2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34172002

RESUMO

BACKGROUND: Levodopa-carbidopa intestinal gel (LCIG) treatment, a unique drug delivery system for patients with advanced Parkinson's disease (PD), is covered by health insurance in Japan since September 2016. Various LCIG procedure/device-associated adverse events (AEs) have been reported; however, reports on their treatment have been limited. This is the first multicenter study to clarify the frequency and timing of device-related AEs. METHODS: Between September 2016 and December 2018, 104 patients introduced to the LCIG treatment for advanced PD in 11 hospitals were included. The patients' characteristics, AEs incidence, AEs time, and tube exchange time were investigated. RESULTS: The median follow-up period was 21.5 months. Minor AE cases were 29.4%, whereas major AE cases were 43.1%. Majority of major AEs (n = 55, 94.8%) were managed with endoscopic treatment, such as tube exchange. Few severe AEs required surgical treatment (n =3, 5.2%). The mean (range) exposure to percutaneous endoscopic gastrojejunostomy (PEG-J) was 14.7 (0-33) months. One year after the LCIG treatment introduction, 55 patients (54.0%) retained the original PEG-J tube. The mean PEG-J tube exchange time was 10.8 ± 7.0 months in all patients, 11.6 ± 4.7 and 10.5 ± 7.7 months in patients with scheduled exchange and who underwent exchange due to AEs, respectively. CONCLUSIONS: Some device-related AEs occurred during the LCIG treatment; however, only few were serious, most of which could be treated with simple procedures or tube replacement with endoscopy. Therefore, the LCIG treatment is feasible and safe and is a unique treatment option for PD, requiring endoscopists' understanding and cooperation.


Assuntos
Antiparkinsonianos , Carbidopa , Derivação Gástrica , Géis , Levodopa , Doença de Parkinson/tratamento farmacológico , Antiparkinsonianos/administração & dosagem , Antiparkinsonianos/efeitos adversos , Antiparkinsonianos/uso terapêutico , Carbidopa/administração & dosagem , Carbidopa/efeitos adversos , Carbidopa/uso terapêutico , Combinação de Medicamentos , Derivação Gástrica/efeitos adversos , Derivação Gástrica/métodos , Géis/administração & dosagem , Géis/efeitos adversos , Géis/uso terapêutico , Humanos , Levodopa/administração & dosagem , Levodopa/efeitos adversos , Levodopa/uso terapêutico , Estudos Retrospectivos
19.
Mater Sci Eng C Mater Biol Appl ; 126: 112148, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34082959

RESUMO

A comprehensive study of release kinetics of a hydrophilic drug from bio-aerogels based on pectin was performed. Pectin aerogels were made by polymer dissolution, gelation (in some cases this step was omitted), solvent exchange and drying with supercritical CO2. Theophylline was loaded and its release was studied in the simulated gastric fluid during 1 h followed by the release in the simulated intestinal fluid. Pectin concentration, initial solution pH and concentration of calcium were varied to tune the properties of aerogel. The kinetics of theophylline release was monitored and correlated with aerogel density, specific surface area, and aerogel swelling and erosion. Various kinetic models were tested to identify the main physical mechanisms governing the release.


Assuntos
Pectinas , Teofilina , Dessecação , Portadores de Fármacos , Géis
20.
Int J Mol Sci ; 22(10)2021 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-34066105

RESUMO

Psoriasis is a chronic skin disease, and it is especially characterized by the occurrence of red, itchy, and scaly eruptions on the skin. The quality of life of patients with psoriasis is decreased because this disease remains incurable, despite the rapid progress of therapeutic methods and the introduction of many innovative antipsoriatic drugs. Moreover, many patients with psoriasis are dissatisfied with their current treatment methods and the form with which the drug is applied. The patients complain about skin irritation, clothing stains, unpleasant smell, or excessive viscosity of the preparation. The causes of these issues should be linked with little effectiveness of the therapy caused by low permeation of the drug into the skin, as well as patients' disobeying doctors' recommendations, e.g., concerning regular application of the preparation. Both of these factors are closely related to the physicochemical form of the preparation and its rheological and mechanical properties. To improve the quality of patients' lives, it is important to gain knowledge about the specific form of the drug and its effect on the safety and efficacy of a therapy as well as the patients' comfort during application. Therefore, we present a literature review and a detailed analysis of the composition, rheological properties, and mechanical properties of polymeric gels as an alternative to viscous and greasy ointments. We discuss the following polymeric gels: hydrogels, oleogels, emulgels, and bigels. In our opinion, they have many characteristics (i.e., safety, effectiveness, desired durability, acceptance by patients), which can contribute to the development of an effective and, at the same time comfortable, method of local treatment of psoriasis for patients.


Assuntos
Fármacos Dermatológicos/administração & dosagem , Géis/administração & dosagem , Polímeros/química , Psoríase/tratamento farmacológico , Animais , Géis/química , Humanos
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