Preparation and Performance of Three-Dimensional Silk FibroinScaffolds with Different Matrix Stiffness / 医用生物力学

Objective After hydrogen bonding between collagen ( COL) and silk fibroin ( SF ) at different concentrations, a composite scaffold with adjustable stiffness was prepared by combining with gel system, and its physical and chemical properties were characterized. Methods SF with different qualities was dissolved in sodium alginate (SA) solution, then COL solution at different concentration and calcium carbonate ( CaCO3 ) powder were added. The hydrogels of SC1, SC2, and SC3 groups were obtained by taking out the mixed solution and adding some gluconic acid lactone ( GDL) powder, and different SF scaffolds were obtained after freeze drying. Results The SF scaffolds with adjustable stiffness were successfully prepared. The compression moduli of SC1, SC2, and SC3 groups were (17. 31±2. 73), (24. 12±1. 81), (32. 54±1. 81) kPa, respectively. The innerstructure of the scaffolds was observed. From SC1 group to SC3 group, pores of the scaffolds were smaller and fewer, and hydrophilicity of the materials become better and better. Conclusions Three-dimensional ( 3D) porous scaffolds with different matrix stiffness can be prepared by changing the concentration of SF and COL solution. The concentration of SF and COL is proportional to the compression modulus, water absorption, water retention and swelling rate of SF scaffolds, while inversely proportional to porosity. The findings of this study are expected to provide theoretical guidance for construction of scaffolds with appropriate matrix stiffness for inducing osteogenic differentiation of mesenchymal stem cells

Bone-derived MSCs encapsulated in alginate hydrogel prevent collagen-induced arthritis in mice through the activation of adenosine A2A/2B receptors in tolerogenic dendritic cells

Tolerogenic dendritic cells (tolDCs) facilitate the suppression of autoimmune responses by differentiating regulatory T cells (Treg). The dysfunction of immunotolerance results in the development of autoimmune diseases, such as rheumatoid arthritis (RA). As multipotent progenitor cells, mesenchymal stem cells (MSCs), can regulate dendritic cells (DCs) to restore their immunosuppressive function and prevent disease development. However, the underlying mechanisms of MSCs in regulating DCs still need to be better defined. Simultaneously, the delivery system for MSCs also influences their function. Herein, MSCs are encapsulated in alginate hydrogel to improve cell survival and retention in situ, maximizing efficacy in vivo. The three-dimensional co-culture of encapsulated MSCs with DCs demonstrates that MSCs can inhibit the maturation of DCs and the secretion of pro-inflammatory cytokines. In the collagen-induced arthritis (CIA) mice model, alginate hydrogel encapsulated MSCs induce a significantly higher expression of CD39+CD73+ on MSCs. These enzymes hydrolyze ATP to adenosine and activate A2A/2B receptors on immature DCs, further promoting the phenotypic transformation of DCs to tolDCs and regulating naïve T cells to Tregs. Therefore, encapsulated MSCs obviously alleviate the inflammatory response and prevent CIA progression. This finding clarifies the mechanism of MSCs-DCs crosstalk in eliciting the immunosuppression effect and provides insights into hydrogel-promoted stem cell therapy for autoimmune diseases.

Immobilization of Lactobacillus bulgaricus with gellan gum and its application in continuous fermentation of D-lactic acid from corn straw / 生物工程学报

Biorefinery of chemicals from straw is an effective approach to alleviate the environmental pollution caused by straw burning. In this paper, we prepared gellan gum immobilized Lactobacillus bulgaricus T15 gel beads (LA-GAGR-T15 gel beads), characterized their properties, and established a continuous cell recycle fermentation process for D-lactate (D-LA) production using the LA-GAGR-T15 gel beads. The fracture stress of LA-GAGR-T15 gel beads was (91.68±0.11) kPa, which was 125.12% higher than that of the calcium alginate immobilized T15 gel beads (calcium alginate-T15 gel beads). This indicated that the strength of LA-GAGR-T15 gel beads was stronger, and the strain was less likely to leak out. The average D-LA production was (72.90±2.79) g/L after fermentation for ten recycles (720 h) using LA-GAGR-T15 gel beads as the starting strain and glucose as the substrate, which was 33.85% higher than that of calcium alginate-T15 gel beads and 37.70% higher than that of free T15. Subsequently, glucose was replaced by enzymatically hydrolyzed corn straw and fermented for ten recycles (240 h) using LA-GAGR-T15 gel beads. The yield of D-LA reached (1.74±0.79) g/(L·h), which was much higher than that of using free bacteria. The wear rate of gel beads was less than 5% after ten recycles, which indicated that LA-GAGR is a good carrier for cell immobilization and can be widely used in industrial fermentation. This study provides basic data for the industrial production of D-LA using cell-recycled fermentation, and provides a new way for the biorefinery of D-LA from corn straw.

Immobilization of mutated xylanase from Neocallimastix patriciarum in E. coli and application for kraft pulp biobleaching / Imobilização de xilanase mutada de Neocallimastix patriciarum em E. coli e aplicação para polpa kraft

Abstract As an important enzyme, xylanase is widely used in the food, pulp, and textile industry. Different applications of xylanase warrant specific conditions including temperature and pH. This study aimed to carry out sodium alginate beads as carrier to immobilize previous reported mutated xylanase from Neocallimastix patriciarum which expressed in E. coli, the activity of immobilization of mutated xylanase was elevated about 4% at pH 6 and 13% at 62 °C. Moreover, the immobilized mutated xylanase retained a greater proportion of its activity than the wide type in thermostability. These properties suggested that the immobilization of mutated xylanase has potential to apply in biobleaching industry.

Resumo Como importante enzima, a xilanase é amplamente utilizada na indústria alimentícia, de celulose e têxtil. Diferentes aplicações de xilanase garantem condições específicas, incluindo temperatura e pH. Este estudo teve como objetivo realizar grânulos de alginato de sódio como carreador para imobilizar xilanase mutada relatada anteriormente de Neocallimastix patriciarum que expressa em E. coli, a atividade de imobilização da xilanase mutada foi elevada em cerca de 4% em pH 6 e 13% a 62 °C. Além disso, a xilanase mutada imobilizada reteve uma proporção maior de sua atividade do que o tipo amplo em termoestabilidade. Essas propriedades sugerem que a imobilização da xilanase mutada tem potencial para aplicação na indústria de biobranqueamento.

Immobilization of mutated xylanase from Neocallimastix patriciarum in E coli and application for kraft pulp biobleaching / Imobilização de xilanase mutada de Neocallimastix patriciarum em E coli e aplicação para polpa kraft

As an important enzyme, xylanase is widely used in the food, pulp, and textile industry. Different applications of xylanase warrant specific conditions including temperature and pH. This study aimed to carry out sodium alginate beads as carrier to immobilize previous reported mutated xylanase from Neocallimastix patriciarum which expressed in E. coli, the activity of immobilization of mutated xylanase was elevated about 4% at pH 6 and 13% at 62 °C. Moreover, the immobilized mutated xylanase retained a greater proportion of its activity than the wide type in thermostability. These properties suggested that the immobilization of mutated xylanase has potential to apply in biobleaching industry.

Como importante enzima, a xilanase é amplamente utilizada na indústria alimentícia, de celulose e têxtil. Diferentes aplicações de xilanase garantem condições específicas, incluindo temperatura e pH. Este estudo teve como objetivo realizar grânulos de alginato de sódio como carreador para imobilizar xilanase mutada relatada anteriormente de Neocallimastix patriciarum que expressa em E. coli, a atividade de imobilização da xilanase mutada foi elevada em cerca de 4% em pH 6 e 13% a 62 °C. Além disso, a xilanase mutada imobilizada reteve uma proporção maior de sua atividade do que o tipo amplo em termoestabilidade. Essas propriedades sugerem que a imobilização da xilanase mutada tem potencial para aplicação na indústria de biobranqueamento.

Immobilization of mutated xylanase from Neocallimastix patriciarum in E. coli and application for kraft pulp biobleaching

Abstract As an important enzyme, xylanase is widely used in the food, pulp, and textile industry. Different applications of xylanase warrant specific conditions including temperature and pH. This study aimed to carry out sodium alginate beads as carrier to immobilize previous reported mutated xylanase from Neocallimastix patriciarum which expressed in E. coli, the activity of immobilization of mutated xylanase was elevated about 4% at pH 6 and 13% at 62 °C. Moreover, the immobilized mutated xylanase retained a greater proportion of its activity than the wide type in thermostability. These properties suggested that the immobilization of mutated xylanase has potential to apply in biobleaching industry.

Resumo Como importante enzima, a xilanase é amplamente utilizada na indústria alimentícia, de celulose e têxtil. Diferentes aplicações de xilanase garantem condições específicas, incluindo temperatura e pH. Este estudo teve como objetivo realizar grânulos de alginato de sódio como carreador para imobilizar xilanase mutada relatada anteriormente de Neocallimastix patriciarum que expressa em E. coli, a atividade de imobilização da xilanase mutada foi elevada em cerca de 4% em pH 6 e 13% a 62 °C. Além disso, a xilanase mutada imobilizada reteve uma proporção maior de sua atividade do que o tipo amplo em termoestabilidade. Essas propriedades sugerem que a imobilização da xilanase mutada tem potencial para aplicação na indústria de biobranqueamento.

Preparation and preliminary evaluation of sodium alginate/agarose/carboxymethyl chitosan spray film dressing carrying platelet rich plasma for wound repair / 中国输血杂志

【Objective】 To develop a spray-on membrane dressing for wound repair containing platelet rich plasma (PRP) sodium alginate (SA)/agarose(AG)/carboxymethyl chitosan (CMCS). 【Methods】 SA/AG/ CMCS were mixed in different proportions to prepare biodegradable quick setting spray (BQSS) by blending film method, and the film-forming time, moisture retention and compression resistance of the prepared BQSS were tested. Then PRP and BQSS were mixed in the proportion of 3∶7, 4∶6, 5∶5, 6∶4 and 7∶3 to prepare PRP-BQSS spray film dressings. The film-forming time, moisture retention, compressive strength, porosity and slow-release effect of growth factors of PRP-BQSS spray film dressings were studied. 【Results】 In the preparation of BQSS compound spray film solution, when SA, AG, CMCS and sterile distilled water were 0.6∶0.6∶0.6∶98.2g, the film-forming time (7.73±0.31) s, moisture retention (75. 54±3.03) % and compression resistance (791.00±68.02) g of the spray-film dressing were the best. The basic properties of PRP-BQSS spray-on film dressings and the release of growth factors show that PRP-BQSS spray-on film dressings can exist in different forms, and with the decrease of PRP concentration percentage, its film-forming time, moisturizing performance and compressive strength showed an upward trend. When the PRP content is 30%, the porosity of the dressing is the highest, about(84.34±0.90)%. The release of platelet-derived growth factor-AA(PDGF-AA), platelet factor-4(PF-4) and transforming growth factor beta (TGF-β) was in a slow upward trend, and the release of the three growth factors was higher than that of PRP group in 48 hours. 【Conclusion】 The preparation method of PRP-BQSS spray film dressing designed in this study is simple and mild, and can form a film quickly, with good biological properties and better growth factor inhibition and sustained-release effect.

Sodium alginate coating simultaneously increases the biosafety and immunotherapeutic activity of the cationic mRNA nanovaccine

The extraordinary advantages associated with mRNA vaccines, including their high efficiency, relatively low severity of side effects, and ease of manufacture, have enabled them to be a promising immunotherapy approach against various infectious diseases and cancers. Nevertheless, most mRNA delivery carriers have many disadvantages, such as high toxicity, poor biocompatibility, and low efficiency in vivo, which have hindered the widespread use of mRNA vaccines. To further characterize and solve these problems and develop a new type of safe and efficient mRNA delivery carrier, a negatively charged SA@DOTAP-mRNA nanovaccine was prepared in this study by coating DOTAP-mRNA with the natural anionic polymer sodium alginate (SA). Intriguingly, the transfection efficiency of SA@DOTAP-mRNA was significantly higher than that of DOTAP-mRNA, which was not due to the increase in cellular uptake but was associated with changes in the endocytosis pathway and the strong lysosome escape ability of SA@DOTAP-mRNA. In addition, we found that SA significantly increased the expression of LUC-mRNA in mice and achieved certain spleen targeting. Finally, we confirmed that SA@DOTAP-mRNA had a stronger antigen-presenting ability in E. G7-OVA tumor-bearing mice, dramatically inducing the proliferation of OVA-specific CLTs and ameliorating the antitumor effect. Therefore, we firmly believe that the coating strategy applied to cationic liposome/mRNA complexes is of potential research value in the field of mRNA delivery and has promising clinical application prospects.

Predatory bacterial hydrogels for topical treatment of infected wounds

Wound infection is becoming a considerable healthcare crisis due to the abuse of antibiotics and the substantial production of multidrug-resistant bacteria. Seawater immersion wounds usually become a mortal trouble because of the infection of Vibrio vulnificus. Bdellovibrio bacteriovorus, one kind of natural predatory bacteria, is recognized as a promising biological therapy against intractable bacteria. Here, we prepared a B. bacteriovorus-loaded polyvinyl alcohol/alginate hydrogel for the topical treatment of the seawater immersion wounds infected by V. vulnificus. The B. bacteriovorus-loaded hydrogel (BG) owned highly microporous structures with the mean pore size of 90 μm, improving the rapid release of B. bacteriovorus from BG when contacting the aqueous surroundings. BG showed high biosafety with no L929 cell toxicity or hemolysis. More importantly, BG exhibited excellent in vitro anti-V. vulnificus effect. The highly effective infected wound treatment effect of BG was evaluated on mouse models, revealing significant reduction of local V. vulnificus, accelerated wound contraction, and alleviated inflammation. Besides the high bacterial inhibition of BG, BG remarkably reduced inflammatory response, promoted collagen deposition, neovascularization and re-epithelization, contributing to wound healing. BG is a promising topical biological formulation against infected wounds.

Carboplatin-loaded surface modified-PLGA nanoparticles confer sustained inhibitory effect against retinoblastoma cell in vitro / Nanopartículas de PLGA com superfície modificada carregada com carboplatina conferem efeito inibitório sustentado contra células de retinoblastoma in vitro

ABSTRACT Purpose: To investigate the antiproliferative effect of carboplatin-loaded surface-modified poly(lactide-co-glycolide) on retinoblastoma cells. Methods: Carboplatin-loaded poly(lactide-co-glycolide) with or without sodium alginate surface modification was prepared using sodium alginate-poly(lactide-co-glycolide) and poly(lactide-co-glycolide). The zeta potential and carboplatin release behavior were investigated. The cellular uptake of the released drug was observed in the retinoblastoma cell line Y79. The inhibitory effect of carboplatin-loaded nanoparticles against the Y79 cell line was evaluated using methyl thiazolyl tetrazolium assay and western blot. Native carboplatin and void nanoparticles without carboplatin loading were used as controls. Results: The zeta potential was -(26.1 ± 3.1) mV for carboplatin-loaded poly(lactide-co-glycolide) and-(43.1 ± 8.1) mV for carboplatin-loaded sodium alginate-poly(lactide-co-glycolide). The burst release percentages of carboplatin-loaded poly(lactide-co-glycolide) and sodium alginate-poly(lactide-co-glycolide) were (40.0% ± 8.2%) and (18.9% ± 4.3%) at 24 hours, respectively. A significant difference was identified regarding drug release between carboplatin-loaded sodium alginate-poly(lactide-co-glycolide) and carboplatin-loaded poly(lactide-co-glycolide). Fluorescence detection revealed that intense uptake of carboplatin into the cytoplasm of the Y79 cell line that was exposed to carboplatin-loaded sodium alginate-poly(lactide-co-glycolide). Carboplatin-loaded poly(lactide-co-glycolide) or sodium alginate-poly(lactide-co-glycolide) exposure inhibited proliferating cell nuclear antigen expression in Y79 cells on day 3. Extension of exposure to day 5 revealed that the sodium alginate-poly(lactide-co-glycolide) surface modification was superior to that of poly(lactide-co-glycolide) in terms of proliferating cell nuclear antigen inhibition. The cell viability test using methyl thiazolyl tetrazolium revealed a similar inhibitory effect. Furthermore, the carboplatin-loaded nanoparticles of lower concentration inhibited cell viability more strongly than native carboplatin of higher concentration in methyl thiazolyl tetrazolium assay. Conclusions: Carboplatin-loaded sodium alginate-poly(lactide-co-glycolide) inhibited retinoblastoma cell proliferation with superior effect as compared with poly(lactide-co-glycolide) and native carboplatin. Sodium alginate surface modification offers a potential strategy for the sustained carboplatin release system.

RESUMO Objetivo: Investigar o efeito antiproliferativo de poli (lactídeo-coglicolídeo) com superfície modificada carregada com carboplatina contra células de retinoblastoma. Métodos: Preparou-se poli (lactídeo-co-glicolídeo) carregado com carboplatina com ou sem alginato de sódio para modifição da superfície, poli com alginato de sódio (lactídeo-co-glicolídeo) e poli (lactídeo-co-glicolídeo). O potencial zeta e o comportamento de liberação de carboplatina foram investigados. A captação celular do fármaco liberado foi observada na linha celular de retinoblastoma Y79. O efeito inibitório das nanopartículas carregadas com carboplatina contra a linha celular Y79 foi avaliado através do ensaio de metiltiazol tetrazólio e Western-blot. Carboplatina nativa e nanopartículas vazias sem carga de carboplatina serviram como controles. Resultados: O potencial zeta de poli carregado com carboplatina (lactídeo-co-glicolídeo) foi - (26,1 ± 3,1) mV versus - (43,1 ± 8,1) mV em poli com alginato de sódio carregado com carboplatina (lactídeo-co-glicolídeo). A percentagem de libertação de explosão de poli carregado com carboplatina (lactídeo-co-glicolídeo) e poli com alginato de sódio (lactídeo-co-glicolídeo) foram (40,0 ± 8,2)% e (18,9 ± 4,3)% às 24 horas, respectivamente. Uma diferença significativa foi identificada em relação à liberação de fármaco entre poli com alginato de sódio carregado com carboplatina (lactídeo-co-glicolídeo) e poli carregado com carboplatina (lactídeo-co-glicolídeo). A detecção de fluorescência revelou que a carboplatina foi assimilada intensamente no citoplasma da linha celular Y79 que foi exposta ao poli com alginato de sódio carregado com carboplatina (lactídeo-co-glicolídeo). A exposição de poli carregada com carboplatina (lactídeo-co-glicolídeo) ou poli com alginato de sódio (lactídeo-co-glicolídeo) inibiu a expressão de antígeno nuclear de proliferação celular em células Y79 no 3º dia. A extensão da exposição no 5º dia revelou que poli com alginato de sódio (lactídeo-co-glicolídeo) para modificação da superfície foi superior a poli (lactídeo-co-glicolídeo) em termos de inibição do antígeno nuclear de proliferação celular. O teste de viabilidade celular via metiltiazol tetrazólio mostrou um efeito inibitório semelhante. Além disso, as nanopartículas carregadas com carboplatina de concentração mais baixa inibiram a viabilidade celular mais fortemente em comparação com a carboplatina nativa de concentração mais alta no ensaio de metiltiazol tetrazólio. Conclusões: Poli com alginato de sódio carregado com carboplatina (lactídeo-co-glicolídeo) inibiu a proliferação de células de retinoblastoma com efeito superior em contraste com poli (lactídeo-co-glicolídeo) e carboplatina nativa. O alginato de sódio para modificação da superfície oferece uma estratégia potencial para o sistema de liberação de carboplatina sustentada.

A comparative study of free laccase and laccase immobilized in copper alginate

Enzyme immobilization has gained considerable attention due to the incredible properties exhibited by the enzymes in immobilized condition. Therefore, in the present study, a comparative analysis of free and immobilized laccase is reported using various substrates. The ideal substrate for immobilization was found to be copper alginate with an immobilization yield of 91.078%. The optimum pH was 4 and 5, respectively, for free and immobilized enzymes while the optimum temperature was found to be 50 and 60?C, respectively. The kinetic parameters Vmax and Km were found from the Line weaver-Burk plot and were 48.076 U/mL and 0.480 mM for free enzyme while 55.55 U/mL and 1.277 mM for the immobilized enzyme, respectively. The catalytic efficiency Kcat was found as 100.01s?1 for free enzyme and 43.5s?1 for its immobilized counterpart. Out of the various metal ions used, Co2+ was found to enhance the activity of an immobilized enzymes. The storage stability of the enzyme was studied and was found that only 32.44% of initial activity was retained by free enzyme whereas, 70.21% of activity was retained by immobilized enzyme upon storage for four weeks at 4?C. The thermal stability studies shows that the immobilized enzyme retained 32.60% of its initial activity and the free enzyme retained 1.14% of initial activity on exposure to 60?C for 3 h. Finally, the reusability of immobilized laccase beads was evaluated by decolorization of methyl orange for five repeated cycles and a percentage decolorization of 32.04% could be retained at the fifth cycle. This study therefore, suggests copper alginate-immobilized beads to be an effective option for various applications

Potential Alendronate Sodium drug carrier by preparation and characterization of sodium alginate cross-linked Montmorillonite

Abstract In drug therapy, it is important to provide therapeutic levels of drug to the site of action and maintain them during the treatment. This work describes the in vitro release of alendronate from sodium alginate cross-linked Montmorillonite (MMT) composite beads. Effect of crosslinking cation, concentration of montmorillonite and media on encapsulation efficiencies, and release profiles of alendronate were studied. Beads were characterized using equilibrium swelling ability study, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Energy-dispersive x-ray spectroscopy (EDX) and scanning electron microscopy (SEM). Results indicate that addition of montmorillonite increases the encapsulation efficiencies and slows down the release rates significantly.

Preparation and in vitro evaluation of Vancomycin loaded Montmorillonite-Sodium Alginate topical gel for wound infection

Abstract Despite decades of research, wound healing remains a significant public health problem. This study aimed to develop and evaluate a topical sodium alginate gel containing vancomycin (Van) loaded MMT NPs for wound healing applications. Van was loaded in MMT at different conditions (pHs of 6, 7 and temperatures of 40, 50 °C) (Van/MMT NPs). The optimum formulation (with the smallest particle size and a high value of zeta potential; 270.8 ± 77.35 nm and -35.96 ± 2.73, respectively) showed a high drug-loading capacity (entrapment efficacy of 96%) and a sustained release pattern of Van (95%) over 480 min. The optimum Van/MMT NPs were embedded into the sodium alginate (SA) gel (Van/MMT NPs/SA gel). The Van/ MMT NPs/SA gel showed a sustained and slow release pattern of Van (95%) over 50 h. FTIR tests revealed the electrostatic interaction between MMT and Van. The broth macrodilution tube method was used to determine the minimum inhibitory concentration (MIC) of Van, Van/ MMT NPs, and Van/MMT NPs/SA gel against Staphylococcus aureus. The results showed the promising antibacterial activity of Van/MMT NPs/SA gel, thus, this gel can be a promising formulation for the management of infected wounds

Advances in the preparation of alginate oligosaccharides and its biological functions / 生物工程学报

Alginate is a group of polyuronic saccharides that are widely used in pharmaceutical and food industry due to its unique physicochemical properties and beneficial health effects. However, the low water solubility and high viscosity of alginate hampered its application. Alginate oligosaccharide (AOS) is a decomposition product of alginate and has received increasing attention due to its low molecular weight, high water solubility, safety, and non-toxicity. The wide-ranging biological functions of AOS are closely related to its structural diversity. AOS with distinct structures and biological functions can be obtained by different methods of preparation. This review summarized the biological functions of AOS reported to date, including anti-tumor, immunomodulatory, anti-inflammatory, antioxidant, prebiotic, and anti-diabetes. The preparation of AOS, as well as the relationship between the structure and biological functions of AOS were discussed, with the aim to provide a reference for further development and application of AOS.

Increases in alginate production and transcription levels of alginate lyase (alyA1) by control of the oxygen transfer rate in Azotobacter vinelandii cultures under diazotrophic conditions

BACKGROUND: Alginates are polysaccharides used in a wide range of industrial applications, with their functional properties depending on their molecular weight. In this study, alginate production and the expression of genes involved in polymerization and depolymerization in batch cultures of Azotobacter vinelandii were evaluated under controlled and noncontrolled oxygen transfer rate (OTR) conditions. RESULTS: Using an oxygen transfer rate (OTR) control system, a constant OTR (20.3 ± 1.3 mmol L 1 h 1 ) was maintained during cell growth and stationary phases. In cultures subjected to a controlled OTR, alginate concentrations were higher (5.5 ± 0.2 g L 1 ) than in cultures under noncontrolled OTR. The molecular weight of alginate decreased from 475 to 325 kDa at the beginning of the growth phase and remained constant until the end of the cultivation period. The expression level of alyA1, which encodes an alginate lyase, was more affected by OTR control than those of other genes involved in alginate biosynthesis. The decrease in alginate molecular weight can be explained by a higher relative expression level of alyA1 under the controlled OTR condition. CONCLUSIONS: This report describes the first time that alginate production and alginate lyase (alyA1) expression levels have been evaluated in A. vinelandii cultures subjected to a controlled OTR. The results show that automatic control of OTR may be a suitable strategy for improving alginate production while maintaining a constant molecular weight.

Sodium alginate-guar gum and carbopol based methotrexate loaded mucoadhesive microparticles for colon delivery: An in vitro evaluation

Methotrexate (MTX) is famous for its therapeutic potential against different cancers including colorectal cancer. Goal of the present investigation was to formulate MTX loaded mucoadhesive microparticles for colon targeting. The optimized formulation (MTX-MS2) was composed of mucoadhesive polymers (sodium alginate, guar gum and carbopol 940) in an appropriate ratio. MTXMS2 was developed by ionic-gelation method. The suitable particle size and zeta potential were found to be 21.10 ± 0.18 µm and 3.01 ± 0.16 mV for MTX-MS2 respectively. The % yield (98.60 ± 2.12), % entrapment efficiency (97.98 ± 1.22) and % drug loading (1.04 ± 0.03) were estimated for MTXMS2. The swelling index (0.99 ± 0.04 θ) and mucoadhesion (97.29 ± 4.61%) were significantly (***P ˂ 0.01) achieved with MTX-MS2 as compared to other formulations. The optimum drug release (96.07 ± 4.52%) was significantly achieved with MTX-MS2 at simulated gastric fluid (pH 7.4) for 36 h in a sustained manner. This profile may be attributed towards excellent mucoadhesivness of the polymers used in the formulation. Therefore, the current investigation suggests that mucoadhesive carrier system could be promising approach for colon delivery. Thus, the proposed work would be helpful for the treatment of colorectal canc

Stability and Sensory Evaluation of an Innovative Antiaging Formulation Based on Marine Ingredients

Abstract The high consumption of antiaging cosmetics represents an outstanding opportunity for the development of new processes and attractive products in the cosmetic industry. Stability studies and sensory analyses are critical steps in the development process and production chain. Here we present a potential antiaging cosmetic product with innovative sensory characteristics. Caviar extract antioxidant properties were firstly evaluated by the DPPH method since it is an important mechanism against skin aging. Ca-alginate beads containing 2% of caviar extract and 0.2% of black pigment were prepared to obtain spheres similar to caviar. The beads were incorporated in a gel phase (hydroxyethylcellulose 2.5%) containing 3% of dimethylaminoethanol. Stability was evaluated in different storage conditions (sunlight exposure, 5 ± 2 °C, 37 ± 2 °C and r.t.) through the parameters: appearance, color and odor, pH (6-7), density (0.98-1.14 g.mL-1), centrifugation and average size. After approval by the Committee for Ethics in Research (n° 3.503.061), 30 volunteers tested the new formulation and answered a questionnaire. At 2%, caviar extract was able to scavenge 10.9% ± 0.58 of DPPH radical. Formulations showed good stability after 90 days, even considering the average size (7.47 ± 0.41 - 8.4 ± 0.65 mm2). 90% of the sensory test participants reported that they would buy the new product. Therefore, the new product developed demonstrates a promising potential as an attractive cosmetic product.

Application of alginate based hydrogels/dressings in wound healing: Sustained, dynamic and sequential release / 中国组织工程研究

BACKGROUND: Alginate can improve the hydrophilic quality of wound dressing, create moist wound microenvironment, and remove wound exudate. Currently, alginate bimolecular materials have been used in the design and development of various wound dressings to improve the efficiency of wound healing. OBJECTIVE: To summarize the research and progress of alginate based hydrogels/dressings in skin wound healing. METHODS: We searched PubMed, Science Direct and CNKI databases from 2000 to 2020 with the English terms of “alginate hydrogel, wound healing, wound dressing, mesenchymal stem cell, growth factor, nanoparticles, diabetic wound, antibiotics, bioactive peptide, three-dimensional printing” and the Chinese terms of “alginate, wound healing”. Based on the inclusion and exclusion criteria, 60 articles were finally reserved for review. RESULTS AND CONCLUSION: (1) The cross-linking of alginate with other organic or inorganic materials can improve the mechanical properties and biodegradability of composite materials, and create a moist and mild wound microenvironment. (2) Alginate based hydrogel/dressing can be used as a delivery platform to load seed cells, growth factors or other bioactive substances to speed up wound healing. (3) It still need to be further explored by researchers to make alginate materials have better cell recognition sites, improve the mechanical properties of composite scaffold materials, control the microstructure of alginate biomaterials and control the dynamic, sustained and sequential release of drugs or cells.

Therapeutic effect of oral vaccine based on glutamate decarboxylase 65 on streptozotocin-induced type 1 diabetic mice / 中国药科大学学报

@#To investigate the therapeutic effect of oral vaccine based on glutamate decarboxylase 65 (GAD65) on streptozotocin (STZ) -induced type 1 diabetic (T1D) mice, the mice model of T1D was established by intraperitoneal injection of low dose multiple STZ. CTB-GADIII encapsulated with calcium alginate (Ca-Alg-GADIII) was formulated using crosslinking technology with sodium alginate and calcium chloride, and was administered intragastric to T1D mice once a week for 5 consecutive weeks.Blood glucose and body weight of the mice were recorded weekly, and pharmacodynamics against T1D of Ca-Alg-GADIII were investigated by glucose tolerance assay (OGTT) and pancreatic histopathological analysis. The levels of glutamic acid decarboxylase antibody (GADA), and insulin autoantibody (IAA) and related cytokines (IL-4, IFN-γ, TGF-β1) in serum were detected by ELISA, and the CD4 + T cell subsets were detected by flow cytometry. The immunological mechanism of oral vaccine against T1D was preliminarily discussed. The results showed that the disease-related indicators improved in immunized mice: fasting blood glucose improved, glucose tolerance and insulin secretion increased, pancreatic injury decreased, autoantibodies like GADA and IAA titers significantly decreased, and CD4 + T cell immune balance in mesenteric lymph node (MLN) and pancreatic lymph node (PLN) improved to some extent. The results suggest that oral vaccine Ca-Alg-GADIII has some therapeutic effect on STZ-induced T1D mice.

Analysis of monosaccharide composition and monosaccharide ratio in propylene glycol alginate sodium sulphate drugs by high performance anion exchange chromatograghy -pulsed amperometric detection / 药学学报

The paper aims to establish the method to determine the monosaccharide composition and monosaccharide ratio in propylene glycol alginate sodium sulphate (PSS). Samples were hydrolyzed with trifluoroacetic acid, neutralized with sodium hydroxide solution after the reaction conditions for sample pretreatment were optimized via orthogonal analysis. A high performance anion exchange chromatograghy (HPAEC) coupled with pulsed amperometric detector (PAD) was performed on a CarboPac®PA20, using 200 mmol·L-1 sodium hydroxide solution and 1 mol·L-1 sodium acetate solution as mobile phase. The established HPAEC-PAD method was validated by testing the linear relationship, precision and accuracy, and showed exclusive, sensitive, rapid and wide use. The monosaccharide composition of PSS from different manufacture can be accurately determined with great significance for the structural identification of PSS.