scholarly journals Physicochemical and Antimicrobial Properties of Thermosensitive Chitosan Hydrogel Loaded with Fosfomycin

Marine Drugs ◽  
2021 ◽  
Vol 19 (3) ◽  
pp. 144
Author(s):  
Luke J. Tucker ◽  
Christine S. Grant ◽  
Malley A. Gautreaux ◽  
Dhanush L. Amarasekara ◽  
Nicholas C. Fitzkee ◽  
...  
Keyword(s):  
Antimicrobial Properties ◽  
Glycerol Phosphate ◽  
Chitosan Hydrogel ◽  
Infection Treatment ◽  
Dependent Inhibition ◽  
Liquid Portion ◽  
Chitosan Hydrogels ◽  
Localized Drug Delivery ◽  
Higher Doses ◽  
Selection Of

Thermosensitive chitosan hydrogels—renewable, biocompatible materials—have many applications as injectable biomaterials for localized drug delivery in the treatment of a variety of diseases. To combat infections such as Staphylococcus aureus osteomyelitis, localized antibiotic delivery would allow for higher doses at the site of infection without the risks associated with traditional antibiotic regimens. Fosfomycin, a small antibiotic in its own class, was loaded into a chitosan hydrogel system with varied beta-glycerol phosphate (β-GP) and fosfomycin (FOS) concentrations. The purpose of this study was to elucidate the interactions between FOS and chitosan hydrogel. The Kirby Bauer assay revealed an unexpected concentration-dependent inhibition of S. aureus, with reduced efficacy at the high FOS concentration but only at the low β-GP concentration. No effect of FOS concentration was observed for the planktonic assay. Rheological testing revealed that increasing β-GP concentration increased the storage modulus while decreasing gelation temperature. NMR showed that FOS was removed from the liquid portion of the hydrogel by reaction over 12 h. SEM and FTIR confirmed gels degraded and released organophosphates over 5 days. This work provides insight into the physicochemical interactions between fosfomycin and chitosan hydrogel systems and informs selection of biomaterial components for improving infection treatment.

scholarly journals The Antimicrobial Properties of Chitosan Can Be Tailored by Formulation

Marine Drugs ◽  
2020 ◽  
Vol 18 (2) ◽  
pp. 96 ◽  
Author(s):  
May Wenche Jøraholmen ◽  
Abhilasha Bhargava ◽  
Kjersti Julin ◽  
Mona Johannessen ◽  
Nataša Škalko-Basnet
Keyword(s):  
Biological Fluid ◽  
Antimicrobial Properties ◽  
Local Therapy ◽  
Topical Administration ◽  
Vaginal Infections ◽  
Chitosan Hydrogel ◽  
Natural Polysaccharide ◽  
Systemic Side Effects ◽  
Chitosan Hydrogels ◽  
And Staphylococcus Aureus

Topical administration of drugs into the vagina can provide local therapy of vaginal infections, preventing the possible systemic side effects of the drugs. The natural polysaccharide chitosan is known for its excellent mucoadhesive properties, safety profile, and antibacterial effects, and thus it can be utilized in improving localized vaginal therapy by prolonging the residence time of a drug at the vaginal site while acting as an antimicrobial in synergy. Therefore, we aimed to explore the potential of chitosan, namely chitosan-coated liposomes and chitosan hydrogel, as an excipient with intrinsic antimicrobial properties. Liposomes were prepared by the thin-film hydration method followed by vesicle size reduction by sonication to the desired size, approximately 200 nm, and coated with chitosan (0.01, 0.03, 0.1, and 0.3%, w/v, respectively). The mucoadhesive properties of chitosan-coated liposomes were determined through their binding efficiency to mucin compared to non-coated liposomes. Non-coated liposomal suspensions were incorporated in chitosan hydrogels forming the liposomes-in-hydrogel formulations, which were further assessed for their texture properties in the presence of biological fluid simulants. The antibacterial effect of chitosan-coated liposomes (0.03%, 0.1% and 0.3%, w/v) and chitosan hydrogels (0.1% and 0.3%, w/w) on Staphylococcus epidermidis and Staphylococcus aureus was successfully confirmed.

Terephthalaldehyde as better crosslinking agent in crosslinked chitosan hydrogel for selective removal of anionic dyes

2021 ◽  
Author(s):  
Madhvi Garg ◽  
Navneet Bhullar ◽  
Bharat Bajaj ◽  
Dhiraj Sud
Keyword(s):  
Crosslinking Agent ◽  
Selective Removal ◽  
Synthetic Dyes ◽  
Anionic Dyes ◽  
Chitosan Hydrogel ◽  
Ultrasound Radiation ◽  
Radiation Induced ◽  
Crosslinked Chitosan ◽  
Chitosan Hydrogels ◽  
Crosslinking Agents

The present manuscript reports the ultrasound radiation induced synthesis of grafted chitosan hydrogels (CAAT and CAAG) using terephthalaldehyde/glutaraldehyde as crosslinking agents and its application for removal of synthetic dyes from...

scholarly journals Advances in Fabricating the Electrospun Biopolymer-Based Biomaterials

2021 ◽  
Vol 12 (2) ◽  
pp. 26
Author(s):  
Sebastian Wilk ◽  
Aleksandra Benko
Keyword(s):  
Mechanical Properties ◽  
Whey Protein ◽  
Antimicrobial Properties ◽  
Protein Isolate ◽  
Review Article ◽  
Animal Tissues ◽  
Green Material ◽  
Good Potential ◽  
Fibrous Morphology ◽  
Selection Of

Biopolymers formed into a fibrous morphology through electrospinning are of increasing interest in the field of biomedicine due to their intrinsic biocompatibility and biodegradability and their ability to be biomimetic to various fibrous structures present in animal tissues. However, their mechanical properties are often unsatisfactory and their processing may be troublesome. Thus, extensive research interest is focused on improving these qualities. This review article presents the selection of the recent advances in techniques aimed to improve the electrospinnability of various biopolymers (polysaccharides, polynucleotides, peptides, and phospholipids). The electrospinning of single materials, and the variety of co-polymers, with and without additives, is covered. Additionally, various crosslinking strategies are presented. Examples of cytocompatibility, biocompatibility, and antimicrobial properties are analyzed. Special attention is given to whey protein isolate as an example of a novel, promising, green material with good potential in the field of biomedicine. This review ends with a brief summary and outlook for the biomedical applicability of electrospinnable biopolymers.

scholarly journals Isolation and Characterization of Lactic Acid Bacteria and Yeasts from Typical Bulgarian Sourdoughs

2021 ◽  
Vol 9 (7) ◽  
pp. 1346
Author(s):  
Mariana Petkova ◽  
Petya Stefanova ◽  
Velitchka Gotcheva ◽  
Angel Angelov
Keyword(s):  
Lactic Acid ◽  
Sequence Analysis ◽  
Lactic Acid Bacteria ◽  
Antimicrobial Properties ◽  
Matter Content ◽  
Starter Cultures ◽  
Rrna Gene ◽  
Dry Matter Content ◽  
Isolation And Characterization ◽  
Selection Of

Traditional sourdoughs in Bulgaria were almost extinct during the centralized food production system. However, a rapidly developing trend of sourdough revival in the country is setting the demand for increased production and use of commercial starter cultures. The selection of strains for such cultures is based on geographical specificity and beneficial technological properties. In this connection, the aim of this study was to isolate, identify and characterize lactic acid bacteria (LAB) and yeasts from typical Bulgarian sourdoughs for the selection of strains for commercial sourdough starter cultures. Twelve samples of typical Bulgarian sourdoughs were collected from different geographical locations. All samples were analyzed for pH, total titratable acidity and dry matter content. Enumeration of LAB and yeast was also carried out. Molecular identification by 16S rDNA sequence analysis was performed for 167 LAB isolates, and 106 yeast strains were identified by ITS1-5.8S-ITS2 rRNA gene partial sequence analysis. The LAB strains were characterized according to their amylolytic and proteolytic activity and acidification capacity, and 11 strains were selected for further testing of their antimicrobial properties. The strains with the most pronounced antibacterial and antifungal activity are listed as recommended candidates for the development of starter cultures for sourdoughs or other food products.

scholarly journals Yb3+-containing chitosan hydrogels induce B-16 melanoma cell anoikis via a Fak-dependent pathway

2019 ◽  
Vol 8 (1) ◽  
pp. 645-660 ◽  
Author(s):  
Yu Miao ◽  
Jiawei Lu ◽  
Junhui Yin ◽  
Changchun Zhou ◽  
Yaping Guo ◽  
...  
Keyword(s):  
Acetic Acid Solution ◽  
Tumor Model ◽  
In Vivo Studies ◽  
High Recurrence Rate ◽  
Mixed Solution ◽  
Chitosan Hydrogel ◽  
Chitosan Hydrogels ◽  
Dermal Cells

AbstractMelanoma is the most lethal dermal tumor, and a high recurrence rate and skin defects are two main serious problems. An antimelanoma material,which effectively inhibits tumor recurrence and possesses excellent biocompatibility, is urgently needed to treat melanoma. In this study, we developed a novel antitumor Yb3+ [Yb(NO3)3]containing chitosan hydrogel (Yb-CS hydrogel) by dissolving Yb(NO3)3 and chitosan in acetic acid solution and forming composite hydrogels by a freeze-drying process after adding NaOH to the mixed solution. In vitro studies demonstrated that the Yb3+ produces effect of inducing cell death in Yb-CS hydrogel. Moreover, we found that the Yb-CS hydrogel inhibited a focal adhesion kinase (FAK)-dependent signaling pathway and induced B-16 cell anoikis. However, the Yb-CS hydrogel was less effective on L929 normal mouse dermal cells. In vivo studies showed that the Yb-CS hydrogel inhibited the recurrence of melanoma in a mouse bare xenograft tumor model. We concluded that the Yb-CS hydrogel could potentially be used in the antimelanoma field, especially in the inhibition of melanoma recurrence.

The development of resistance to metachloridine inPlasmodium gallinaceumin Chicks

Parasitology ◽  
1953 ◽  
Vol 42 (3-4) ◽  
pp. 277-286 ◽  
Author(s):  
Ann Bishop ◽  
Elspeth W. McConnachie
Keyword(s):  
Growth Rate ◽  
Drug Resistance ◽  
Normal Population ◽  
Rapid Development ◽  
Cross Resistance ◽  
Development Of Resistance ◽  
The Gift ◽  
Higher Doses ◽  
Resistance Tests ◽  
Selection Of

1. An increase in resistance to metachloridine of more than 100-fold was obtained within a few weeks in a strain ofPlasmodium gallinaceumtreated with gradually increasing doses of the drug and maintained in young chicks by blood-inoculation at intervals of 2–3 days.2. There was no evidence that the rapid development of resistance arose by the selection of highly resistant individuals present in the normal population.3. Two strains ofP. gallinaceumpassaged through chicks treated with 0·025 mg. doses of the drug gradually became resistant to greater concentrations than that to which they had been exposed, though their growth rate decreased when they were inoculated into birds receiving higher doses of the drug.4. In both strains maintained in birds treated with 0·025 mg. doses of the drug, resistance reached a maximum beyond which it did not increase.5. Cross-resistance tests failed to show any relationship in mode of action between meta-chloridine and pamaquin, mepacrine, quinine or chloroquine. A strain ofP. gallinaceum, highly resistant to metachloridine, showed slight resistance to sulphadiazine, sulphapyridine and sulphathiazole, but none to sulphanilamide or proguanil.We are indebted to the Cyanamid Products Ltd., London, for the gift of the Folvite used in these experiments.

Does caloric restriction induce hormesis?

2000 ◽  
Vol 19 (6) ◽  
pp. 320-329 ◽  
Author(s):  
A Turturro ◽  
B S Hass ◽  
R W Hart
Keyword(s):  
Caloric Restriction ◽  
Dose Response ◽  
Nonhuman Primates ◽  
Proliferative Potential ◽  
Response Curves ◽  
Aging Research ◽  
The Impact ◽  
Higher Doses ◽  
Hormetic Response ◽  
Selection Of

The question of whether caloric restriction (CR) is hormetic is addressed in terms of two common defini-tions of the term. In terms of the older definition, i.e., a growth-stimulatory effect when lower doses of a compound which resulted in growth inhibition at higher doses, CR is better characterized as a co-hormetic (i.e., a paradigm which at relatively “low doses,” in combina-tion with some stimulus, will evince increased growth (proliferation) and at higher “doses” will inhibit this increased proliferation) rather than a hormetic agent. Mechanisms such as cellular selection of cellular subpopulations, increases in receptor efficiency, and preservation of cellular proliferative potential can inter-act with agents and produce increased growth as long as the CR is not too severe. In terms of a broader definition, i.e., nonmonotonic dose-response behavior of a compound for any adverse response, CR appears to be hormetic, both as a result of body weight (BW) loss and other potential mechanisms. The impact of changes in BW, or frank CR, can be considered a component of every test for hormesis, and is thus capable for interaction with any other agent. The changes that BW loss (or CR) induce are so profound that any aspect of an agent's action-metabolism, pharmacokinetics, pharmacodynamics-can modulate the response of an organism to an agent. Similarly, other effects of a chemical that induce BW loss, e.g., physical activity or temperature dysregulation, can also induce dose-response curves that appear hormetic. The interaction of the hormetic agents of BW loss and CR can influence agent tests. Controlling these factors may make it possible to dissect the key components of a hormetic response. In addition, the effects of CR or BW loss appear to extrapolate well across species [Colman R, Kemnitz JW. Aging experi-ments using nonhuman primates. In: Yu BP (Ed), Methods in Aging Research. CRC Press, Boca Raton, FL, 1999, pp. 249-267]. Thus there is some reason to believe that these hormetic factors may be important for humans, and may already be a factor for tests of potentially adverse agents already conducted in humans.

scholarly journals Polyamide fabric coated with a dihydroxyacetone-loaded chitosan hydrogel for a cosmeto-textile application

2019 ◽  
Vol 50 (4) ◽  
pp. 526-542
Author(s):  
Isabel Solé ◽  
Susana Vílchez ◽  
Núria Montanyà ◽  
Maria José García-Celma ◽  
Marcela Ferrándiz ◽  
...  
Keyword(s):  
Active Component ◽  
Optical Microscope ◽  
Dark Field ◽  
Cross Linking ◽  
Dialysis Membrane ◽  
Chitosan Hydrogel ◽  
Evaluation Panel ◽  
Polyamide Fabric ◽  
Chitosan Hydrogels ◽  
Cryogenic Scanning Electron Microscopy

Cosmeto-textiles, which allow the administration of molecules when in contact with the skin, are increasingly being developed by cosmetic industries. We have designed an innovative approach for cosmeto-textile products, based on the impregnation of textile fibers with chitosan hydrogels, which have been cross-linked with genipin and loaded with dihydroxyacetone, which is an active component that induces sunless tanning. Dihydroxyacetone-loaded chitosan hydrogels have been prepared and characterized by means of cryogenic scanning electron microscopy (cryo-SEM). The images showed that genipin cross-linking decreases the mesh distance of hydrogels. The release of dihydroxyacetone from these cross-linked genipin chitosan hydrogels has been studied by a dialysis membrane method. These dihydroxyacetone-loaded chitosan hydrogels have been incorporated to polyamide textiles by a simple padding technique. The presence of dihydroxyacetone on these textiles has been detected by hyperspectral imaging on a dark field high resolution optical microscope. Finally, the performance of fabrics as cosmeto-textiles, with a tanning effect, has been evaluated by skin-colorimetry measured with an evaluation panel of 10 people. The results have demonstrated that dihydroxyacetone-loaded textiles produce a tanning effect on skin, and incorporation of dihydroxyacetone-loaded chitosan hydrogels into polyamide fabrics represents a friendly and appropriate strategy to obtain a cosmeto-textile with tanning effect.

scholarly journals Effects of Crosslinking Methods on Network Structure and Enzymatic Degradation of Methacrylate-Functionalized Chitosan Hydrogel

2018 ◽  
Author(s):  
Juhong Ahn ◽  
Jungju Ryu ◽  
Kwangho Song ◽  
Jungwook Kim
Keyword(s):  
Biomedical Applications ◽  
Enzymatic Degradation ◽  
Network Structures ◽  
Porous Network ◽  
Chitosan Hydrogel ◽  
Shear Moduli ◽  
Network Heterogeneity ◽  
X Ray Scattering ◽  
Degradation Behaviors ◽  
Chitosan Hydrogels

Polysaccharides, such as hyaluronic acid, alginate, or chitosan, can be modified by addition of reactive functional groups to enable chemical crosslinking. Here, we studied how different methods of crosslinking methacrylate-functionalized chitosan affected the network structures of the resulting hydrogels. We then investigated how the porous network structures in turn influenced stiffness, macromolecular diffusion through the pores, and enzymatic degradation. All these properties are relevant for utilization of the chemically crosslinked hydrogels in biomedical applications, including tissue engineering and delivery of therapeutic agents. We made chitosan hydrogels using four crosslinking methods, which differ by type and by reaction kinetics. We found that four chitosan hydrogels having identical polymer fractions at an equilibrium swelling exhibited marked differences in their shear moduli, rate of dextran diffusion, and especially their enzymatic degradation behaviors. We inferred that these differences originated in variations among network structures, which were characterized by the formation of chain bundles and associated network heterogeneity as determined by small-angle X-ray scattering analysis.

scholarly journals FOLIAR FEEDING WITH ZINC AS A BIOFORTIFICATION STRATEGY IN MAIZE

2019 ◽  
Vol 18 (2) ◽  
pp. 281-289
Author(s):  
ANA STELLA FREIRE GONÇALVES ◽  
RENZO GARCIA VON PINHO ◽  
LUIZ ROBERTO GUIMARÃES GUILHERME ◽  
JOSÉ EDUARDO BORGES FURTADO ◽  
FRANCIELLY DE CÁSSIA PEREIRA
Keyword(s):  
Zinc Concentration ◽  
Zea Mays L ◽  
Nutrient Content ◽  
Micronutrient Deficiencies ◽  
Acid Digestion ◽  
Growing Seasons ◽  
Maize Genotypes ◽  
Higher Doses ◽  
Agronomic Biofortification ◽  
Selection Of

Human zinc malnutrition is a concern in the contemporary scenario. Ranked among the serious micronutrient deficiencies and considered a major cause of child mortality, especially in developing countries. Cereals, such as maize (Zea mays L.), food source in these countries, show low zinc concentration. In view of this, biofortification has been shown promise to increase the nutrient content in staple foods and to improve their nutritional quality. The aim of this study was to evaluate the potential of maize genotypes in relation to yield and zinc concentration in grains and leaves as a function of zinc sulfate doses in two growing seasons. A total of 17 commercial hybrids were evaluated in three doses (0, 5, and 10g L-1 ha-1). The zinc concentration was quantified by acid digestion, followed by atomic absorption spectrophotometer analysis. Any change was observed in grain yield as a function of the doses. Higher doses applied near flowering resulted in higher concentrations of the micronutrient in the grains. However, the concentrations in the grains were, on average, below the value established by the Harvest Plus biofortification program. The results provide information for the selection of genotypes with zinc uptake potential aiming at food safety through agronomic biofortification.

Sign in / Sign up

Export Citation Format

Share Document