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1.
Food Chem ; 368: 130825, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34496332

RESUMO

Protein-polysaccharide nanocomplexes system could improve the low stability of ACNs, making ACNs become a potential and stable pH indicator. In this study, intelligent colorimetric film was designed to monitor pork freshness by incorporating ACNs-loaded ovalbumin-propylene glycol alginate nanocomplexes (ACNs-loaded OVA-PGA) into polyvinyl alcohol/ glycerol (PG) matrix. The intelligent film (PG/ACNs-loaded OVA-PGA film) presented well barrier performance (lower water vapor permeability and light transmittance at 200-600 nm). Fourier transform infrared spectroscopy further confirmed the hydrogen bonds among film-forming components. Moreover, Scanning electron microscope and X-ray diffraction showed that ACNs-loaded OVA-PGA was uniformly distributed in film matrix but decreased the crystallinity of polyvinyl alcohol. PG/ACNs-loaded OVA-PGA film had distinguishable colorimetric response to pH 2.0-11.0 buffers and volatile ammonia. In the test, PG/ACNs-loaded OVA-PGA film displayed visible color alterations from purplish-red to dark-blue as pork freshness decreased, suggesting it can be used in intelligent packaging for real-time monitoring freshness of meat products.


Assuntos
Carne de Porco , Carne Vermelha , Alginatos , Animais , Antocianinas , Colorimetria , Embalagem de Alimentos , Concentração de Íons de Hidrogênio , Ovalbumina , Suínos
2.
Food Chem ; 368: 130902, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34438176

RESUMO

Overcoming harsh gastric environment is still a challenging to bioactive proteins, microencapsulation provides one strategy in designing this protection barrier. In this work, bovine serum albumin and ovalbumin were chosen as model proteins, while polylysine-alginate complex was fabricated for microencapsulation purpose. Both of the protein-loaded microcapsules had regular internal microstructures. The model protein's embedding increased the thermal stability of the microcapsules. Both of the protein-loaded microcapsules had a slow release rate in simulated gastric fluids (pH 3.0), while a sustained release profile in simulated intestinal fluids (pH 6.4), indicating an excellent tolerance to the acidic gastric environment. The microencapsulation process was mild and had no influence on the protein's molecular weight, while a slight peak shifting occurred in the secondary structure of the released proteins. The developed microcapsules could be explored as a kind of vehicle for bioactive proteins applied in functional foods, health care products and medical formulations.


Assuntos
Polilisina , Soroalbumina Bovina , Alginatos , Cápsulas , Ovalbumina
3.
J Hazard Mater ; 421: 126742, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34348210

RESUMO

The recovery of rare-earth from secondary sources is essential for cleaner production. The development of natural biocomposites is promising for this purpose. Sericin is a waste protein from silk manufacturing. The highly polar groups on the surface of sericin facilitate blending and crosslinking with other polymers to produce biocomposites with improved properties. In this work, we investigate ytterbium recovery onto a natural biocomposite based on sericin/alginate/poly(vinyl alcohol) (SAPVA) in packed-bed column, aiming to establish a profitable application for sericin. Effects of flow rate and ytterbium inlet concentration showed that the highest exhaustion biosorption capacity (128.39 mg/g) and lowest mass transfer zone (4.13 cm) were reached under the operating conditions of 0.03 L/h and 87.95 mg/L. Four reusability cycles were performed under the optimum operating conditions using 0.3 mol/L HNO3. Ytterbium recovery was highly successful; desorption efficiency was higher than 97% and a final ytterbium-rich concentrate (3870 mg/L) was 44 times higher than input concentration. Regenerated beads characterization showed that the cation exchange mechanism plays a major function in continuous biosorption of ytterbium. SAPVA beads also showed higher biosorption/desorption performance for ytterbium than other competing ions. These results suggest the application of SAPVA may be an alternative for large-scale ytterbium recovery.


Assuntos
Sericinas , Adsorção , Alginatos , Álcool de Polivinil , Itérbio
4.
Zhongguo Yi Liao Qi Xie Za Zhi ; 45(5): 546-550, 2021 Sep 30.
Artigo em Chinês | MEDLINE | ID: mdl-34628770

RESUMO

OBJECTIVE: To study the safety of alginate based gastric mucosal protective adhesive and its feasibility as a submucosal injection. METHODS: The feasibility of using alginate-based gastric mucosal protective gel as submucosal injection was evaluated by in vitro gastric mucosal uplift test in pigs and in vivo gastric mucosal uplift test in rats. The safety of alginate based gastric mucosa protective adhesive was evaluated by cytotoxicity test, acute toxicity test and oral mucosa stimulation test according to GB/T 16886 series standard of biological evaluation of medical devices. RESULTS: After injection of different concentrations of alginate base mucosal protective adhesive solution, the uplift height was significantly higher than that of normal saline (P<0.05). Gastric mucosal protection glue has no cytotoxic oral mucosal irritation or acute toxicity. CONCLUSIONS: Gastric mucosa protector is a promising new medical device product with feasibility and good biocompatibility as submucosal uplift injection agent.


Assuntos
Adesivos , Alginatos , Animais , Estudos de Viabilidade , Mucosa Gástrica , Injeções , Ratos , Suínos
5.
Enzyme Microb Technol ; 151: 109916, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34649687

RESUMO

Alginate oligosaccharides are enzymolysis products of alginate with versatile bioactivities and their industrial preparation was limited by the insufficient activity and unsatisfying thermostability of alginate lyases. The structure-function information about PL18 alginate lyases was seldom reported since which few positive mutants of PL18 alginate lyases were generated. In present study, a mutant of PL18 alginate lyase E226K was expressed intracellularly and taken as parent for further modification. Site I211 at the lid loop 1 and sites E276, Y292 and R294 at the predicted entrance were chosen as engineering targets based on the E226K-PM4 binding mode in prereaction-state MD simulation and 29 mutants were constructed, from those, the variant E226K/I211T/R294V was screened out as the best mutant (showing 4.78-fold increased catalytic efficiency and the half-time t1/245℃ increased up to 557 min from 89 min). MD simulations indicated that the affinity of E226K/I211T/R294V towards alginate was improved due to the optimized energy distribution of active center, more flexible loops around catalytic cleft and larger substrate entrance. The more efficient proton transmitting endowed E226K/I211T/R294V higher activity and the more complicated intraprotein interactions together with stronger backbone rigidity were responsible for the improved thermostability of E226K/I211T/R294V than E226K. The success in this study enriches the structure-function information of PL18 alginate lyases and provides hints for their further design.


Assuntos
Alginatos , Polissacarídeo-Liases , Catálise , Oligossacarídeos , Polissacarídeo-Liases/genética , Polissacarídeo-Liases/metabolismo , Especificidade por Substrato
6.
Soft Matter ; 17(37): 8465-8473, 2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34586146

RESUMO

Electroconductive biocompatible hydrogels with tunable properties have extensively been taken into account in tissue engineering applications due to their potential to provide suitable microenvironmental responses for the cells. In the present study, novel electroconductive hydrogels are designed and synthesized by reacting oxidized alginate with polypyrrole-grafted gelatin copolymer (PPy-g-gelatin) via formation of a Schiff-base linkage. The influence of the composition and the concentration of the components on the compressive modulus and functional performance of the hydrogels is investigated. The conductivity of the hydrogels measured by a two-probe method increased by increasing the level of polypyrrole-grafted gelatin, and a conductivity of 0.7753 S m-1 was exhibited by the hydrogel composed of 8% w/v polypyrrole-grafted gelatin (oxidized alginate:gelatin:polypyrrole-grafted gelatin; 30 : 35 : 35% v/v). The hydrogel compressive modulus was shown to be enhanced by increasing the total concentration of hydrogel. The characteristic features of the prepared hydrogels, including swelling ratio, volume fraction, cross-link density, and mesh size, are also studied and analyzed. Besides, the conductive hydrogels have a smaller mesh size and higher cross-link density than the non-conductive hydrogels. However, the hydrogels with high cross-link density, small mesh size, and large pore size presented higher electroconductivity as a result of easier movement of the ions throughout the hydrogel. These conductive hydrogels exhibited electrical conductivity and biodegradability with cell viability, implying potential as scaffolds for tissue engineering.


Assuntos
Gelatina , Hidrogéis , Alginatos , Polímeros , Pirróis , Engenharia Tecidual , Tecidos Suporte
7.
Mater Sci Eng C Mater Biol Appl ; 129: 112393, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34579912

RESUMO

Peripheral nerve injury can cause various degrees of damage to the morphological structure and physiological function of the peripheral nerve. At present, compared with "gold standard" autologous nerve transplantation, tissue engineering has certain potential for regeneration and growth; however, achieving oriented guidance is still a challenge. In this study, we used 3D bioprinting to construct a nerve scaffold of RSC96 cells wrapped in sodium alginate/gelatin methacrylate (GelMA)/bacterial nanocellulose (BNC) hydrogel. The 5% sodium alginate+5% GelMA+0.3% BNC group had the thinnest lines among all groups after printing, indicating that the inherent shape of the scaffold could be maintained after adding BNC. Physical and chemical property testing (Fourier transform infrared, rheometer, conductivity, and compression modulus) showed that the 5% alginate+5% GelMA+0.3% BNC group had better mechanical and rheological properties. Live/dead cell staining showed that no mass cell death was observed on days 1, 3, 5, and 7 after printing. In the 5% alginate+5% GelMA group, the cells grew and formed linear connections in the scaffold. This phenomenon was more obvious in the 5% alginate+5% GelMA+0.3% BNC group. In the 5% alginate+5% GelMA+0.3% BNC group, S-100ß immunofluorescence staining and cytoskeleton staining showed oriented growth. Polymerase chain reaction (PCR) array results showed that mRNA levels of related neurofactors ASCL1, POU3F3, NEUROG1, DLL1, NOTCH1 and ERBB2 in the 5%GelMA+0.3%BNC group were higher than those of other groups. Four weeks after implantation in nude mice, RSC96 cells grew and proliferated well, blood vessels grew, and S-100ß immunofluorescence was positive. These results indicate that a 3D-bioprinted sodium alginate/GelMA/BNC composite scaffold can improve cell-oriented growth, adhesion and the expression of related factors. This 3D-bioprinted composite scaffold has good biocompatibility and is expected to become a new type of scaffold material in the field of neural tissue engineering.


Assuntos
Bioimpressão , Gelatina , Alginatos , Animais , Bactérias , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Hidrogéis/farmacologia , Metacrilatos , Camundongos , Camundongos Nus , Proteínas do Tecido Nervoso , Impressão Tridimensional , Engenharia Tecidual , Tecidos Suporte
8.
Nano Lett ; 21(18): 7495-7504, 2021 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-34495662

RESUMO

Structured nanoassemblies are biomimetic structures that are enabling applications from nanomedicine to catalysis. One approach to achieve these spatially organized architectures is utilizing amphiphilic diblock copolymers with one or two macromolecular backbones that self-assemble in solution. To date, the impact of alternating backbone architectures on self-assembly and drug delivery is still an area of active research limited by the strategies used to synthesize these multiblock polymers. Here, we report self-assembling ABC-type alginate-based triblock copolymers with the backbones of three distinct biomaterials utilizing a facile conjugation approach. This "polymer mosaic" was synthesized by the covalent attachment of alginate with a PLA/PEG diblock copolymer. The combination of alginate, PEG, and PLA domains resulted in an amphiphilic copolymer that self-assembles into nanoparticles with a unique morphology of alginate domain compartmentalization. These particles serve as a versatile platform for co-encapsulation of hydrophilic and hydrophobic small molecules, their spatiotemporal release, and show potential as a drug delivery system for combination therapy.


Assuntos
Alginatos , Micelas , Interações Hidrofóbicas e Hidrofílicas , Polietilenoglicóis , Polímeros
9.
Mater Sci Eng C Mater Biol Appl ; 128: 112262, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474821

RESUMO

Chitosan/alginate (Chi/Alg) nanoparticles as a non-viral vector for the Smad4 encoding plasmid were optimized utilizing D-optimal design based on the nanoparticles/plasmid ratio, Chi/Alg MW, and preparation method type. Following the optimization and validation of the best formula, morphology studies and FTIR measurements were performed to evaluate the optimized Chi/Alg/S NPs. Toxicity (MTT assay) and transfection studies were performed for the best formula in comparison with Lipofectamine 2000, and Polyethyleneimine (PEI) and evaluated using Green Fluorescence Protein (GFP) assay, Flow cytometry, and RT-PCR. The model predicted a particle size of 111 nm, loading efficacy (LE) of 43%, cumulative release (CMR) of 39%, the ζ-potential of +50 mV, and PDI of 0.13. The predicted point condition was as follows: NP ratio = 13, Chi/Alg MW ratio = 2.35, and preparation method type = 1. Microscopic findings revealed that the shape of nanoparticles was spherical. The Chi/Alg/S nanoparticles showed no toxicity and transfection efficacy of 29.9% was observed in comparison with Lipofectamine (35.5%) and PEI (30.9%).


Assuntos
Quitosana , Nanopartículas , Alginatos , Técnicas de Transferência de Genes , Tamanho da Partícula , Transfecção
10.
Mater Sci Eng C Mater Biol Appl ; 128: 112264, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474823

RESUMO

Injectable self-healing hydrogels of natural polysaccharides that mimic the extracellular matrix to promote cellular growth are attractive materials for wound healing. Here, a novel hydrogel was fabricated based on carboxymethyl chitosan (CS) and aldehyde functionalized sodium alginate via Schiff base reaction. To enhance the hydrogel's properties, carboxymethyl-functionalized polymethyl methacrylate (PMAA) short nanofibers were obtained through sodium hydroxide-treated polymethyl methacrylate nanofibers, and added to a CS solution. Gelation time was determined for different hydrogels including 0-5 mg/mL PMAA short nanofibers. The nanofiber hydrogels were tested for their injectability and self-healing abilities and were demonstrated to be easily injectable with excellent self-healing abilities. Additionally, in vitro cytocompatibility experiments, good interaction between the cultured cells and hydrogels was seen. Further, the polysaccharide hydrogel containing short PMMA nanofibers significantly facilitated wound healing in rats compared with the polysaccharide hydrogel and control groups. Thus, the developed hydrogel has great potential for wound healing applications.


Assuntos
Quitosana , Nanofibras , Alginatos , Animais , Hidrogéis , Polissacarídeos , Ratos , Cicatrização
11.
Mater Sci Eng C Mater Biol Appl ; 128: 112336, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474887

RESUMO

This study used methylcellulose (MC) to improve the printability of the alginate dialdehyde-gelatin (ADA-GEL) based bioink. The printability as well as the capability to maintain shape fidelity of ADA-GEL could be enhanced by the addition of 9% (w/v) MC. Moreover, the properties of the ink crosslinked with Ca2+ and Ba2+ were investigated. The samples crosslinked with Ba2+ were more stable and stiffer than the Ca2+ crosslinked samples. However, both Ca2+ and Ba2+ crosslinked samples exhibited a similar trend of MC release during incubation under cell culture conditions. The toxicity test indicated that both samples (crosslinked with Ca2+ and Ba2+) exhibited no toxic potential. The fabrication of cell-laden constructs using the developed bioinks was evaluated. The viability of ST2 cells in Ba2+ crosslinked samples increased while for Ca2+ crosslinked samples, a decreased viability was observed over the incubation time. After 21 days, cell spreading in the hydrogels crosslinked with Ba2+ occurred. However, a certain degree of cell damage was observed after incorporating the cells in the high viscosity bioink.


Assuntos
Bioimpressão , Gelatina , Alginatos , Sobrevivência Celular , Hidrogéis , Metilcelulose , Impressão Tridimensional , Tecidos Suporte
12.
Mater Sci Eng C Mater Biol Appl ; 128: 112344, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474894

RESUMO

A micron scale alginate based 3D platform embedded with a carbon dot pH sensor, that enables continuous growth monitoring of encapsulated cells in real time is reported. The alginate based 3D micro-scaffold closely mimics a tumor microenvironment by providing a spatial demarcation and making it possible to encapsulate different cells in close proximity. The micro-scaffold contains carbon dot based nanosensors that enable real time monitoring of pH change in the tumor microenvironment avoiding the need for end-point assays for studying cellular growth. The micro-scaffolds have heterogeneous architecture and a hypoxic core region can be observed in as less as 96 h of culture. In this completely synthetic platform, there also exist the flexibility of artificially modifying the porosity of the micro-scaffold as per the requirement of the studies where a denser ECM mimic is required. The micro-scaffolds were conducive for cell growth as suggested by the enhanced functional profile of hepatocellular carcinoma cells and positively influence the genetic expression of the cell specific markers. Additionally, similar to a 3D tumor, non-homogeneous diffusion of molecules is also observed making this an ideal platform for cancer modelling and drug screening.


Assuntos
Alginatos , Neoplasias , Técnicas de Cultura de Células , Proliferação de Células , Humanos , Porosidade , Tecidos Suporte , Microambiente Tumoral
13.
Viruses ; 13(9)2021 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-34578399

RESUMO

Over the decades, the world has witnessed diverse virus associated pandemics. The significant inhibitory effects of marine sulfated polysaccharides against SARS-CoV-2 shows its therapeutic potential in future biomedical applications and drug development. Algal polysaccharides exhibited significant role in antimicrobial, antitumor, antioxidative, antiviral, anticoagulant, antihepatotoxic and immunomodulating activities. Owing to their health benefits, the sulfated polysaccharides from marine algae are a great deal of interest globally. Algal polysaccharides such as agar, alginate, carrageenans, porphyran, fucoidan, laminaran and ulvans are investigated for their nutraceutical potential at different stages of infection processes, structural diversity, complexity and mechanism of action. In this review, we focus on the recent antiviral studies of the marine algae-based polysaccharides and their potential towards antiviral medicines.


Assuntos
Antivirais/farmacologia , Organismos Aquáticos/química , Polissacarídeos/farmacologia , Alga Marinha/química , Viroses/epidemiologia , Alginatos/química , Alginatos/farmacologia , Antivirais/química , Glucanos/química , Glucanos/farmacologia , Humanos , Estrutura Molecular , Pandemias , Polissacarídeos/química , Viroses/tratamento farmacológico , Viroses/etiologia , Viroses/prevenção & controle
14.
Arch Microbiol ; 203(9): 5805-5816, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34528110

RESUMO

In the present work, the biodegradation of phenol by alginate immobilized Chlamydomonas reinhardtii cells was investigated. Immobilized Chlamydomonas reinhardtii could remove up to 1300 µmol/L of phenol within 10 days of cultivation. Metabolic activity was demonstrated by the extracellular release of catechol. Beads prepared at high concentrations of alginate (5-6% w/v) were found to protect microalgae against the strong inhibitory effects of phenol on the photosynthetic apparatus. Cells immobilized in beads of higher concentrations of alginate exhibited higher metabolic efficiencies compared to those prepared by lower alginate concentrations. Lower alginate concentrations (3-4% w/v) led to increased cell leakage, while the presence of phenol in the medium had the opposite effect in all alginate concentrations. Resuspension of immobilized microalgae in a medium containing a growth-promoting substrate, led to colony formation only on the external surface of alginate beads, indicating that acetic acid and consequently phenol, could not penetrate the internal of alginate beads. The significance of the work is that alginate immobilized Chlamydomonas substantially minimize the required volume of the aqueous medium and improve the economics and commercial application prospects of the process.


Assuntos
Chlamydomonas reinhardtii , Fenol , Alginatos , Biodegradação Ambiental , Fenóis
15.
Lab Chip ; 21(18): 3412-3419, 2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34472548

RESUMO

Droplet microfluidics has recently emerged as a powerful platform for a variety of biomedical applications including microreactors, bioactive compound encapsulation, and single cell culture and analysis; all these applications require long-term droplet stability, which, however, makes breaking the emulsion and retrieving the loaded samples difficult. Herein, we developed a novel class of thermo-responsive fluorosurfactants to control the droplet status simply by temperature. The surfactants were synthesized by coupling perfluorinated polyethers (PFPEs) with a thermo-responsive block of poly(N-isopropylacrylamide) (pNIPAM) or poly(2-ethyl-2-oxazoline) (pEtOx) with lower critical solution temperature (LCST). These diblock surfactants can stabilize the emulsion at temperatures below LCST due to the hydrophilic head, which became hydrophobic upon increasing the ambient temperature above LCST, thereby destabilizing the droplets and realizing demulsification simply via temperature control. The diblock surfactant can be applied for templating cell encapsulation using alginate microgels, which allowed one-step and high-throughput microfluidic generation of cell-laden microgels without compromising cell viability. This non-invasive, on-demand demulsification strategy provides a high degree of freedom for microencapsulation and on-demand recovery of the samples or reaction products within the droplets, which opens a new avenue for a wide range of applications of droplet-templating microfluidics.


Assuntos
Microfluídica , Tensoativos , Alginatos , Emulsões , Temperatura
16.
Molecules ; 26(17)2021 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-34500607

RESUMO

Based on the adsorption performance of a porous nanocomposite with limestone (LS), activated carbon (AC) and sodium alginate (SG), a unique, multifunctional LS-AC-SG nanocomposite absorbent was designed and prepared for extracting antibiotics and drugs from aqueous solutions. The composite exhibited the following advantages: quick and simple to prepare, multifunctionality and high efficiency. Amoxicillin (AMX) and diclofenac (DCF) were chosen as the conventional antibiotic and the drug, respectively. The prepared nanocomposite's physicochemical characteristics were calculated through numerous characterization methods. The structure of the surface was made up of interconnected pores that can easily confine pollutants. The surface area was measured to be 27.85 m2/g through BET analysis. The results show that the maximum absorption capacity of amoxicillin and diclofenac was 99.6% and 98.4%, respectively, at a contact time of 40 min. The maximum removal of amoxicillin and diclofenac was reached at pH = 2. Adsorption analysis revealed that adsorption isotherm and kinetic data matched the pseudo-first-order kinetic and the Langmuir isotherm models. The results imply that the synthesized nanocomposites have the capacity to remove amoxicillin (AMX) and diclofenac (DCF) from aqueous solutions.


Assuntos
Alginatos/química , Antibacterianos/química , Carbonato de Cálcio/química , Carvão Vegetal/química , Nanocompostos/química , Preparações Farmacêuticas/química , Soluções/química , Água/química , Adsorção , Amoxicilina/química , Diclofenaco/química , Concentração de Íons de Hidrogênio , Cinética , Porosidade , Poluentes Químicos da Água/química , Purificação da Água/métodos
17.
Environ Monit Assess ; 193(10): 666, 2021 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-34545422

RESUMO

Lead (Pb) is a potentially toxic element with significant environmental interest. Simple and sensitive analytical methods are necessary to allow determination of this element at trace levels using sample preparation procedures related to green chemistry. For this, calcium alginate beads (CA-beads), a low-cost and environmentally friendly biopolymer, have been proposed for extraction and preconcentration of Pb2+ in river water samples and determination by flame atomic absorption spectrometry (FAAS). CA-beads were prepared and applied to extract and preconcentrate Pb2+ in river water samples, providing an enrichment factor (EF) of 50, enhancement factor (E) of 54, a detection limit of 2 µg L-1, and a relative standard deviation < 5%. The extraction of Pb2+ in CA-beads achieved good selectivity, with recoveries from 94.8 to 100.2% in real samples, demonstrating the good accuracy of the proposed method. The results were also compared to those obtained by ICP-MS. The reuse of CA-beads was evaluated for six cycles, and under these conditions, the extraction and preconcentration efficiency of Pb2+ were not significantly affected. The developed methodology was applied to determine Pb2+ in water samples from rivers that are part of the hydrographic areas of Tibagi and Pitangui Rivers, in which the Pb2+ concentration was less than 2 µg L-1, a concentration lower than that established by Brazilian legislation for class I and II rivers.


Assuntos
Chumbo , Poluentes Químicos da Água , Alginatos , Monitoramento Ambiental , Estudos de Viabilidade , Concentração de Íons de Hidrogênio , Rios , Espectrofotometria Atômica , Água , Poluentes Químicos da Água/análise
18.
BMC Res Notes ; 14(1): 384, 2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34583753

RESUMO

OBJECTIVE: We aimed to detect the effect of a couple of parameters including Alg, H2O2, and HRP concentrations on the gelation time of Alg-based hydrogels using an enzymatic cross-linked procedure. RESULTS: NMR, UV-Vis, and ATR-FTIR analyses confirmed the conjugation of Ph to the Alg backbone. Data showed gelation time was delayed with the increase and reduction of H2O2 and HRP, respectively. We noted that hydrogel consisted of 1.2% (w/v) Alg, 5 U HRP, and 100 mM H2O2 yielded an appropriate gelation time with appropriate mechanical properties. The addition of 0.5% (v/v) Col developed hydrogel increased the gelation time. The data showed that Alg, HRP, and H2O2 with the ratio of 1:0.54:0.54 had proper physicochemical features for cartilage engineering.


Assuntos
Cartilagem Articular , Hidrogéis , Alginatos , Peroxidase do Rábano Silvestre , Peróxido de Hidrogênio , Engenharia Tecidual
19.
Int J Mol Sci ; 22(17)2021 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-34502249

RESUMO

The replacement of damaged or degenerated articular cartilage tissue remains a challenge, as this non-vascularized tissue has a very limited self-healing capacity. Therefore, tissue engineering (TE) of cartilage is a promising treatment option. Although significant progress has been made in recent years, there is still a lack of scaffolds that ensure the formation of functional cartilage tissue while meeting the mechanical requirements for chondrogenic TE. In this article, we report the application of flock technology, a common process in the modern textile industry, to produce flock scaffolds made of chitosan (a biodegradable and biocompatible biopolymer) for chondrogenic TE. By combining an alginate hydrogel with a chitosan flock scaffold (CFS+ALG), a fiber-reinforced hydrogel with anisotropic properties was developed to support chondrogenic differentiation of embedded human chondrocytes. Pure alginate hydrogels (ALG) and pure chitosan flock scaffolds (CFS) were studied as controls. Morphology of primary human chondrocytes analyzed by cLSM and SEM showed a round, chondrogenic phenotype in CFS+ALG and ALG after 21 days of differentiation, whereas chondrocytes on CFS formed spheroids. The compressive strength of CFS+ALG was higher than the compressive strength of ALG and CFS alone. Chondrocytes embedded in CFS+ALG showed gene expression of chondrogenic markers (COL II, COMP, ACAN), the highest collagen II/I ratio, and production of the typical extracellular matrix such as sGAG and collagen II. The combination of alginate hydrogel with chitosan flock scaffolds resulted in a scaffold with anisotropic structure, good mechanical properties, elasticity, and porosity that supported chondrogenic differentiation of inserted human chondrocytes and expression of chondrogenic markers and typical extracellular matrix.


Assuntos
Alginatos/química , Materiais Biocompatíveis/química , Quitosana/química , Hidrogéis/química , Engenharia Tecidual/métodos , Tecidos Suporte/química , Agrecanas/genética , Agrecanas/metabolismo , Anisotropia , Proteína de Matriz Oligomérica de Cartilagem/genética , Proteína de Matriz Oligomérica de Cartilagem/metabolismo , Diferenciação Celular , Proliferação de Células , Condrócitos/metabolismo , Condrogênese , Colágeno/metabolismo , Colágeno Tipo II/genética , Colágeno Tipo II/metabolismo , Força Compressiva , Feminino , Glicosaminoglicanos/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Cultura Primária de Células , Eletricidade Estática
20.
Int J Mol Sci ; 22(18)2021 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-34576102

RESUMO

Bionanocomposite materials have been designed as a promising route to enhance biopolymer properties, especially for food packaging application. The present study reports the preparation of bionanocomposite films of alginate with different loadings of pure reduced graphene oxide (rGO) or of mixed zinc oxide-rGO (ZnO-rGO) fillers by solvent casting. Sepiolite is used to make compatible rGO with the hydrophilic matrix. The addition of fillers to alginate matrix maintains the low water solubility promoted by the calcium chloride treatment, and, additionally, they demonstrate a weaker mechanical properties, and a slight increase in water vapor permeability and wettability. Due to the properties of ZnO-rGO, the alginate bionanocomposites show an increase of electrical conductivity with the increase of filler content. While the highest electrical conductivity (0.1 S/m) is achieved by the in-plane measurement, it is in the through-plane measurement the remarkable enhancement of almost 30 times greater than the alginate film. With 50% of ZnO-rGO filler, the bionanocomposites present the highest antioxidant and antibacterial activities. The combination of electrical conductivity with bioactive properties makes these films promising not only to extend food shelf-life but also to allow packaged food sterilization at low temperature.


Assuntos
Alginatos/química , Condutividade Elétrica , Embalagem de Alimentos , Nanocompostos/química , Anti-Infecciosos/farmacologia , Antioxidantes/farmacologia , Módulo de Elasticidade , Escherichia coli/efeitos dos fármacos , Grafite/química , Testes de Sensibilidade Microbiana , Nanocompostos/ultraestrutura , Permeabilidade , Solubilidade , Análise Espectral Raman , Staphylococcus aureus/efeitos dos fármacos , Vapor , Resistência à Tração , Água/química , Molhabilidade , Difração de Raios X , Óxido de Zinco/química
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