The accumulation of chitin waste from the seafood industry is a serious environmental problem. However, this residue can be degraded by chitinases and its subproducts, such as chitosan, economically exploited. In this study, a chitinase producer bacteria, identified as Paenibacillus illinoisensis, was isolated from the Brazilian coastal city of Terra de Areia - Rio Grande Do Sul (RS) and was immobilized within alginate beads to evaluate its chitinase production. The alginate beads containing cells presented an average size of 4 mm, 99% of immobilization efficiency and increased the enzymatic activity in 40.71% compared to the free cells. The biomass during enzymatic production increased 62.01% and the total cells leaked from the alginate beads corresponded to 6.46% after 96 h. Immobilized cells were reused in a sequential batch system and remained stable for production for up to four 96-h cycles, decreasing only 21.04% of the initial activity at the end of the fourth cycle. Therefore, the methodology used for cell immobilization resulted in adequate beads to maintain cell viability during the enzymatic production, increasing enzymatic activity, showing low cell leakage from the support and appropriate recyclable capacity.
- MeSH
- algináty chemie MeSH
- chitinasy * MeSH
- kyseliny hexuronové chemie MeSH
- půda MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Brazílie MeSH
The theory of glucose-responsive composite membranes for the planar diffusion and reaction process is extended to a microsphere membrane. The theoretical model of glucose oxidation and hydrogen peroxide production in the chitosan-aliginate microsphere has been discussed in this manuscript for the first time. We have successfully reported an analytical derived methodology utilizing homotopy perturbation to perform the numerical simulation. The influence and sensitive analysis of various parameters on the concentrations of gluconic acid and hydrogen peroxide are also discussed. The theoretical results enable to predict and optimize the performance of enzyme kinetics.
The use of autologous fat grafting in breast reconstruction still requires optimization. Fat survival and calcification are the main issues that affect the outcomes of the procedure. In this study, a cell-based therapy utilizing laminin-alginate beads (LABs) as carriers was proposed to promote cell survival and adipogenesis by providing short-term physical support and facilitate nutrient diffusion of the implants. Laminin-modified alginate beads were fabricated by immobilizing laminin onto ring-opened alginate, used to encapsulate 3T3-L1 preadipocytes, and evaluated in vitro and in vivo. LABs as preadipocyte carriers showed better biocompatibility and stability than unmodified alginate beads. Preadipocytes in LABs had higher survival rate and enhanced adipogenesis than those in unmodified alginate beads. In vivo studies showed that LABs gradually degraded and the sites were replaced by newly formed fat tissues, and new blood vessels were also observed. 7T-MRI study mimicking clinical fat grafting showed that LABs carrying adipose stem cells improved the results of conventional fat grafts. Therefore, we believe that LABs represent promising cell carriers and can be potentially used for the reconstruction of breasts or other soft tissues in the future.
- MeSH
- adipogeneze * MeSH
- algináty chemie MeSH
- buňky 3T3-L1 MeSH
- imobilizované buňky * metabolismus transplantace MeSH
- kyselina glukuronová chemie MeSH
- kyseliny hexuronové chemie MeSH
- laminin chemie MeSH
- myši inbrední NOD MeSH
- myši SCID MeSH
- myši MeSH
- potkani Sprague-Dawley MeSH
- tukové buňky * metabolismus transplantace MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
External ionotropic gelation offers a unique possibility to entrap multivalent ions in a polymer structure. The aim of this experimental study was to prepare new drug-free sodium alginate (ALG) particles cross-linked by Cu2+ions and to investigate their technological parameters (particle size, sphericity, surface topology, swelling capacity, copper content, release of Cu2+ions, mucoadhesivity) and biological activity (cytotoxicity and efficiency against the most common vaginal pathogens-Herpes simplex, Escherichia coli, Candida albicans) with respect to potential vaginal administration. Beads prepared from NaALG dispersions (3 or 4%) were cross-linked by Cu2+ions (0.5 or 1.0 M CuCl2) using external ionotropic gelation. Prepared mucoadhesive beads with particle size over 1000 μm exhibited sufficient sphericity (all ˃0.89) and copper content (214.8-249.07 g/kg), which increased with concentration of polymer and hardening solution. Dissolution behaviour was characterized by extended burst effect, followed by 2 h of copper release. The efficiency of all samples against the most common vaginal pathogens was observed at cytotoxic Cu2+concentrations. Anti-HSV activity was demonstrated at a Cu2+concentration of 546 mg/L. Antibacterial activity of beads (expressed as minimum inhibition concentration, MIC) was influenced mainly by the rate of Cu2+release which was controlled by the extent of swelling capacity. Lower MIC values were found for E. coli in comparison with C. albicans. Sample ALG-3_1.0 exhibited the fastest copper release and was proved to be the most effective against both bacteria. This could be a result of its lower polymer concentration in combination with smaller particle size and thus larger surface area.
- MeSH
- algináty chemie farmakologie MeSH
- antibakteriální látky farmakologie MeSH
- gely chemie MeSH
- kationty MeSH
- kyselina glukuronová chemie farmakologie MeSH
- kyseliny hexuronové chemie farmakologie MeSH
- měď chemie farmakologie MeSH
- polymery chemie MeSH
- rozpustnost MeSH
- skot MeSH
- velikost částic MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Alginate is a copolymer of β-d-mannuronate and α-l-guluronate, which are present in the cell wall of brown algae. The hypocholesterolemic and hypolipidemic activities of alginate and its derivative, which is prepared by a reaction with octadecylamine, were compared in rats fed diets containing cholesterol and palm fat at 10 and 50g/kg, respectively. Amidated alginate at 20g/kg significantly decreased serum cholesterol from 2.93 to 2.00μmol/mL, serum triacylglycerols from 1.66 to 0.92μmol/mL, hepatic cholesterol from 17.5 to 5.9μmol/g, and total hepatic lipids from 67.4 to 51.7mg/g. Alginate at 20g/kg significantly reduced hepatic cholesterol to 13.1μmol/g, but did not influence serum cholesterol, triacylglycerols, and total hepatic lipids. Amidated alginate significantly increased the faecal concentrations of neutral sterols from 98.7 to 122.4μmol/g DM, but decreased faecal concentration of bile acids from 19.4 to 14.0μmol/g DM. In samples of intestinal contents, taurine-conjugated bile acids dominated glycine conjugates. The supplementation of diets with cholesterol significantly increased the expression of hepatic cholesterol 7α-hydroxylase, especially in rats that received cholesterol without alginate or amidated alginate. In conclusion, amidated alginate is an effective hypocholesterolemic agent that is more efficient than its parent polysaccharide.
- MeSH
- algináty chemie farmakologie MeSH
- amidy chemie MeSH
- anticholesteremika chemie farmakologie MeSH
- játra účinky léků metabolismus MeSH
- krysa rodu rattus MeSH
- kyselina glukuronová chemie farmakologie MeSH
- kyseliny hexuronové chemie farmakologie MeSH
- metabolismus lipidů účinky léků MeSH
- potkani Wistar MeSH
- přijímání potravy účinky léků MeSH
- tělesná hmotnost účinky léků MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
Alginate gels are an outstanding biomaterial widely applicable in tissue engineering, medicine, and pharmacy for cell transplantation, wound healing and efficient bioactive agent delivery, respectively. This contribution provides new and comprehensive insight into the atomic-resolution structure and dynamics of polyvalent ion-cross-linked alginate gels in microbead formulations. By applying various advanced solid-state NMR (ssNMR) spectroscopy techniques, we verified the homogeneous distribution of the cross-linking ions in the alginate gels and the high degree of ion exchange. We also established that the two-component character of the alginate gels arises from the concentration fluctuations of residual water molecules that are preferentially localized along polymer chains containing abundant mannuronic acid (M) residues. These hydrated M-rich blocks tend to self-aggregate into subnanometer domains. The resulting coexistence of two types of alginate chains differing in segmental dynamics was revealed by 1H-13C dipolar profile analysis, which indicated that the average fluctuation angles of the stiff and mobile alginate segments were about 5-9° or 30°, respectively. Next, the 13C CP/MAS NMR spectra indicated that the alginate polymer microstructure was strongly dependent on the type of cross-linking ion. The polymer chain regularity was determined to systematically decrease as the cross-linking ion radius decreased. Consistent with the 1H-1H correlation spectra, regular structures were found for the gels cross-linked by relatively large alkaline earth cations (Ba2+, Sr2+, or Ca2+), whereas the alginate chains cross-linked by bivalent transition metal ions (Zn2+) and trivalent metal cations (Al3+) exhibited significant irregularities. Notably, however, the observed disordering of the alginate chains was exclusively attributed to the M residues, whereas the structurally well-defined gels all contained guluronic acid (G) residues. Therefore, a key role of the units in M-rich blocks as mediators promoting the self-assembly of alginate chains was experimentally confirmed. Finally, combining 2D 27Al 3Q/MAS NMR spectroscopy with density functional theory (DFT) calculations provided previously unreported insight into the structure of the Al3+ cross-linking centers. Notably, even with a low residual amount of water, these cross-linking units adopt exclusively 6-fold octahedral coordination and exhibit significant motion, which considerably reduces quadrupolar coupling constants. Thus, the experimental strategy presented in this study provides a new perspective on cross-linked alginate structure and dynamics for which high-quality diffraction data at the atomic resolution level are inherently unavailable.
Alginic acid is a suitable material for modification to prepare new derivatives because of presence of its carboxyl groups. The high content of carboxyl groups over the entire length of its chain renders it an easily modifiable material with a possibility of achieving a high degree of substitution in the prepared derivatives. The salt of alginic acid (sodium alginate) is readily commercially available and is widely used in many branches of chemistry. Alginic acid was thus selected as the substrate for amidation. The amidation used two-steps: methyl esterification followed by amino-de-alkoxylation. The aim of this study was to prepare highly substituted derivatives with different polysaccharide chain characteristics. As such, the alginic acid was modified by the two-step amidation based on the esterification of the alginic acid carboxyl groups by reaction with methanol and further amino-de-alkoxylation (aminolysis) of the obtained methyl ester with amidation reagents (n-alkylamines, hydrazine and hydroxylamine). The purity and substitution degree of the prepared derivatives were monitored by vibration spectroscopic methods (FTIR and FT Raman) and organic elemental analysis. These analytical methods confirmed the preparation of highly or moderately substituted N-alkylamides, hydrazide and hydroxamic acid of alginic acid.
White rot fungi (WRF) are applicable to biodegradation of recalcitrant pollutants. However, excessive biomass growth typical for WRF cultivation can hinder their large scale applications. Therefore, immobilization of Irpex lacteus to liquid-core alginate beads restricting excessive mycelium growth and simultaneously keeping high degradation rate of pollutants was tested. Effective diffusivities of dyes to the beads varied from (2.98 ± 0.69) × 10(-10) to (10.27 ± 2.60) × 10(-10) m(2)/s. Remazol Brilliant Blue R (RBBR), Reactive Orange 16 (RO16), and Naphthol Blue Black (NBB) were used as model dyes. The immobilized fungus decolorized model dyes when applied both in microwell plates and in fluidized bed reactors. Using the microwell plates, the apparent reaction rate constants ranged from (2.06 ± 0.11) × 10(-2) to (11.06 ± 0.27) × 10(-2) 1/h, depending on the dye used and its initial concentration. High initial concentrations negatively affected the dye decolorization rate. No fungal growth outside the beads was observed in fluidized bed reactors and thus no operational problems linked to an excessive biomass growth occurred. When RBBR was decolorized in subsequent batches in the fluidized bed reactor, the apparent reaction rate constant increased from (11.63 ± 0.35) × 10(-2) to (29.26 ± 7.19) × 10(-2) 1/h.
- MeSH
- algináty chemie MeSH
- barvicí látky metabolismus MeSH
- biodegradace MeSH
- chemické látky znečišťující vodu metabolismus MeSH
- imobilizované buňky chemie metabolismus MeSH
- kyselina glukuronová chemie MeSH
- kyseliny hexuronové chemie MeSH
- mycelium chemie růst a vývoj metabolismus MeSH
- Polyporales chemie růst a vývoj metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
Silver/Alginate/Nicotinamide nanoparticles composite (Ag/ALG/Nic) was prepared and used for the first time to fabricate wound dressing material. Sodium alginate (ALG) was used as reducing and stabilizing agents for preparation of silver nanoparticles (Ag-NPs). Effect of concentrations of alginate (ALG) on the particle size of silver were studied and confirmed by different techniques like UV/vis spectroscopy, transmission electron microscope (TEM) and dynamic light scattering (DLS). Nonwoven viscous fabrics were used as a carrier for silver/alginate/nanoparticles composite by impregnated the nonwoven fabrics as per the padding-curing technique. Nicotinamide (Nic) as anti-inflammatory drug was entrapped into Ag-NPS/ALG/nonwoven fabrics. Scanning electron microscope and energy dispersive x-ray (SEM-EDX) were used to evaluate the presence of Ag/ALG/Nic nanoparticles composite anchored the nonwoven fabrics. The antibacterial activity of the Ag/ALG/Nic wound dressing material was evaluated against Escherichia coli (E. coli) and Staphylococcus Aureus (St. Aureus). The wound healing and histological studied were evaluated by using burn diabetic rat animals.
- MeSH
- algináty chemie MeSH
- antiflogistika nesteroidní farmakologie MeSH
- aplikace kožní MeSH
- Escherichia coli účinky léků růst a vývoj MeSH
- experimentální diabetes mellitus chemicky indukované komplikace farmakoterapie mikrobiologie MeSH
- infekce vyvolané Escherichia coli komplikace farmakoterapie mikrobiologie patologie MeSH
- kovové nanočástice chemie ultrastruktura MeSH
- králíci MeSH
- krysa rodu rattus MeSH
- kůže účinky léků mikrobiologie patologie MeSH
- kyselina glukuronová chemie MeSH
- kyseliny hexuronové chemie MeSH
- nanokompozity chemie ultrastruktura MeSH
- niacinamid farmakologie MeSH
- obvazy * MeSH
- popálení farmakoterapie mikrobiologie patologie MeSH
- stafylokokové infekce komplikace farmakoterapie mikrobiologie patologie MeSH
- Staphylococcus aureus účinky léků růst a vývoj MeSH
- streptozocin MeSH
- stříbro chemie MeSH
- textilie MeSH
- velikost částic MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Polysaccharide-based nanocomplexes, intended for simultaneous encapsulation and controlled release of 5-Fluorouracil (5-FU) and Temozolomide (TMZ) were developed via the complexation method using chitosan, alginic and polygalacturonic acid. Investigation focused on the influence of polysaccharides on the properties of the system and amelioration of the stability of the drugs, in particular TMZ. The dimensions of particles and their ζ-potential were found to range between 100 and 200nm and -25 to +40mV, respectively. Encapsulation efficiency varied from 16% to over 70%, depending on the given system. The influence of pH on the release and co-release of TMZ and 5-FU was evaluated under different pH conditions. The stability of the loaded drug, in particular TMZ, after release was evaluated and confirmed by LC-MS analysis. Results suggested that the amount of loaded drug(s) and the release rate is connected with the weight ratio of polysaccharides and the pH of the media. One-way ANOVA analysis on the obtained data revealed no interference between the drugs during the encapsulation and release process, and in particular no hydrolysis of TMZ occurred suggesting that CS-ALG and CS-PGA would represent interesting carriers for multi-drug controlled release and drugs protection.
- MeSH
- algináty chemie MeSH
- antimetabolity antitumorózní chemie MeSH
- antitumorózní látky alkylující chemie MeSH
- chitosan chemie MeSH
- dakarbazin analogy a deriváty chemie MeSH
- fixní kombinace léků MeSH
- fluorouracil chemie MeSH
- kyselina glukuronová chemie MeSH
- kyseliny hexuronové chemie MeSH
- léky s prodlouženým účinkem chemie MeSH
- nanočástice chemie MeSH
- nosiče léků chemie MeSH
- pektiny chemie MeSH
- prekurzory léčiv chemie MeSH
- příprava léků MeSH
- stabilita léku MeSH
- uvolňování léčiv MeSH
- Publikační typ
- časopisecké články MeSH
