To prepare materials with improved recycling capability, new flexible biodegradable polyurethane foams, in which non-degradable polyether polyol was partly substituted by the bio-polyols based on ...cellulose or starch derivatives were synthesized. The incorporation of bio-polyols into the foams’ structures as well as their influence on the foam thermal stability was assessed by Fourier-transformed infrared spectroscopy and thermogravimetric analysis analyses. The ecotoxicological aspects of the newly synthesized foams were investigated by extracting the samples using freshwater as a solvent followed by applying the microbiotest screening toxkit under trade name “Thamnotoxkit F™” with larvae of freshwater shrimps
Thamnocephalus platyurus
.
The study investigates the use of fiber carriers, based on biopolymeric gums as potential candidates for cosmetic and dermatological applications, in particular for skin regeneration. Gum arabic ...(GA), xanthan gum (XA), and gum karaya (GK) were used as the main gum materials for the fibers, which were prepared by centrifugal spinning from an aqueous solution. These solutions of different mass gum ratios were blended with poly (ethylene oxide) (PEO) for better spinnability. Finally, vitamins E and C were added to selected solutions of gums. The resulting fibers were extensively investigated. The morphology and structure of all fibers were investigated by scanning electron microscopy and Fourier transformed infrared spectroscopy. Most importantly, they were characterized by the release of vitamin E loaded in the fibers using UV-VIS spectroscopy. The presentation will show that the newly prepared fibers from GA and PEO represent a very promising material for cosmetic and dermatologic applications.
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A comparison of the electrostatic and centrifugal spinning of poly(vinyl alcohol) and poly(vinyl pyrrolidone) is shown in terms of the resulting fiber morphology and the process conditions. Specific ...parameters of centrifugal spinning, such rotational speed of spinneret and the relative humidity, were extensively investigated in details. Morphologies and diameters of resulting fiber mats were investigated by a scanning electron microscopy and compared between the two spinning techniques. The results revealed that formation of fibers is mainly affected by the initial polymer concentrations (and resulting viscosities) of polymeric solutions, which is in line with previous reports. However, the key novel finding of this work is that increasing relative humidity during centrifugal spinning process leads to greatly reduced fiber diameters to the levels typical for electrospinning. The obtained comparison is discussed and clearly shows technological advantages of the centrifugal spinning over electrospinning, enabling quantitative production of fibers with same or similar diameters.
Collagen I-based foams were modified with calcined or noncalcined hydroxyapatite or calcium phosphates with various particle sizes and pores to monitor their effect on cell interactions. The ...resulting scaffolds thus differed in grain size, changing from nanoscale to microscopic, and possessed diverse morphological characteristics and resorbability. The materials' biological action was shown on human bone marrow MSCs. Scaffold morphology was identified by SEM. Using viability test, qPCR, and immunohistochemical staining, we evaluated the biological activity of all of the materials. This study revealed that the most suitable scaffold composition for osteogenesis induction is collagen I foam with calcined hydroxyapatite with a pore size of 360 ± 130 µm and mean particle size of 0.130 µm. The expression of osteogenic markers RunX2 and ColI mRNA was promoted, and a strong synthesis of extracellular protein osteocalcin was observed. ColI/calcined HAP scaffold showed significant osteogenic potential, and can be easily manipulated and tailored to the defect size, which gives it great potential for bone tissue engineering applications.
Crosslinked 3D porous collagen-polysaccharide scaffolds, prepared by freeze-drying, were modified with bovine platelet lysate (BPL) and evaluated in terms of chemical, physical and biological ...properties. Natural antibacterial polysaccharides like chitosan, chitin/chitosan-glucan complex and calcium salt of oxidized cellulose (CaOC) incorporated in collagen scaffolds affected not only chemo-physical properties of the composite scaffolds but also improved their biological properties, especially when BPL was presented. Lipophilic BPL formed microspheres in porous scaffolds while reduced by half their swelling ratio. The resistance of collagen sponges to hydrolytic degradation in water depended strongly on chemical crosslinking varying from 60 min to more than one year. According to in-vitro tests, chemically crosslinked scaffolds exhibited a good cellular response, cell–matrix interactions, and biocompatibility of the material. The combination of collagen with natural polysaccharides confirmed a significant positive synergistic effect on cultivation of cells as determined by MTS assay and PicoGreen method, as well as on angiogenesis evaluated by ex ovo Chick Chorioallantoic Membrane (CAM) assay. Contrary, modification only by BLP of pure collagen scaffolds exhibited decreased biocompatibility in comparison to unmodified pure collagen scaffold. We propose that the newly developed crosslinked collagen sponges involving bioactive additives could be used as scaffold for growing cells in systems with low mechanical loading in tissue engineering, especially in dermis replacement, where neovascularization is a crucial parameter for successful skin regeneration.
Modification of thermogelling biodegradable copolymers with functional groups enables further covalent crosslinking of physical micelle‐based hydrogels formed at specific temperature in water. The ...resulting hybrid hydrogel network exhibits an increase in stiffness and degradation stability. In this work, synthesized well‐defined thermoresponsive α,ω‐itaconyl‐poly(d,l‐lactide‐co‐glycolide)‐b‐poly(ethylene glycol)‐b‐poly(d,l‐lactide‐co‐glycolide) (α,ω‐itaconyl‐PLGA‐PEG‐PLGA) macromonomers with a high degree of itaconyl‐substitution providing free double bonds are photocrosslinked in water at both 25 and 37 °C using lithium phenyl‐2,4,6‐trimethylbenzoylphosphinate (LiTPO) acting as water‐soluble non‐toxic photoinitiator. The effect of LiTPO on the thixotropic behavior of macromonomer in water at 25 °C without irradiation is evaluated. With the addition of a low amount of the photoinitiator (0.1 wt%), the degree of copolymer thixotropy increases. However, further increase in the photoinitiator concentration (0.5–3 wt%) leads to a lower degree of thixotropy. The photoinitiator is presumably interfering with the micellar self‐assembly of the copolymer. This trend is also reflected in photocrosslinking efficiency, where the hybrid hydrogel networks with the highest storage moduli are achieved with very low concentrations of the photoinitiator (0.1 wt%) at 25 °C, while this trend is reversed at 37 °C. The hydrolytic stability of hydrogels prepared at 37 °C from 17 wt% macromonomer solution with 1% LiTPO exceeds 22 days.
Additional covalent crosslinking of thermogelling α,ω‐itaconyl‐PLGA‐PEG‐PLGA in water using lithium phenyl‐2,4,6‐trimethylbenzoylphosphinate as a photoinitiator is studied. The photoinitiator influences self‐assembly of the copolymer, that also affects the photocrosslinking efficiency at 25 °C. On the other hand, the photocrosslinking at 37 °C is less affected by the photoinitiator concentration.
The newest trends in wound healing management and the development of the next generation of dressings are pointing toward natural polymeric materials with important beneficial properties such as ...antimicrobial effects, renewability, easier process of preparation, and biological activity. Here, we present the preparation and in vitro evaluation of a unique biopolymeric blend composed of natural polymers based on the positively charged polysaccharide chitosan and negatively charged gum karaya. A plate lysis assay of gum karaya and chitosan solution mixtures proved the synergistic antimicrobial effect against specific strains of both Gram-positive and Gram-negative bacteria and yeast. This polymeric mixture was used for hydrogel film preparation and determination of the composition effect on physical properties (swelling behavior in different solvents, pH, diffusion mechanism, hydrolytic stability, mechanical and optical properties). While the pure gum karaya with poly(vinyl alcohol) exhibited the highest hydrolytic degradation (68%), the mixture of poly(vinyl alcohol) and gum karaya with chitosan (in the 25:75 ratio) exhibited the lowest degradation value (41%) due to the strong physical interactions. Cytotoxicity tests performed with hydrogel extracts using two different in vitro models, adherent fibroblasts (NIH3T3) and non-adherent suspension B-lymphocytes (BaF3), exhibited excellent biocompatibility and no cytotoxicity. As expected, the antimicrobial activity of 3-day film extracts showed a significantly improved antimicrobial effect of mixtures involving a chitosan biopolymer. The physical and biological properties of prepared biopolymer-based hydrogels meet the requirements of modern wound dressings.
Novel triazole-based aluminum complex {
O
,
O
′-4,5-P(O)Ph
2
tz-AlMe
2
was studied as the catalyst for the ring-opening polymerization of caprolactone (ε-CL) in chlorobenzene. In the presence of ...methanol, isopropanol, and bifunctional poly(ethylene glycol), the catalytic system produced polymers with high conversion (81–85 %) but broader distribution (
M
w
/
M
n
= 1.5–1.8). The system of catalyst and benzyl alcohol produced relative monodisperse PCLs (
M
w
/
M
n
~ 1.2) with defined molecular weight at 1/1ratio, 60 °C and an initial concentration of ε-CL equal to 0.5 mol/L.
Novel hydrolytically stable gelatin nanofibers modified with sodium or calcium salt of oxycellulose were prepared by electrospinning method. The unique inhibitory effect of these nanofibers against ...Escherichia coli bacteria was examined by luminometric method. Biocompatibility of these gelatin/oxycellulose nanofibers with eukaryotic cells was tested using human lung adenocarcinoma cell line NCI-H441. Cells firmly adhered to nanofiber surface, as determined by scanning electron microscopy, and no signs of cell dying were detected by fluorescent live/dead assay. We propose that the newly developed gelatin/oxycellulose nanofibers could be used as promising scaffold for lung disease modeling and anti-cancer drug testing.
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•Novel hydrolytically stable gelatin nanofibers modified with oxycellulose were prepared by electrospinning.•ATR–FTIR spectroscopy and EDX confirmed the presence of oxycellulose in the nanofibers.•Nanofibers modified with calcium salt of oxycellulose exhibited significant antibacterial properties.•Nanofibers modified with sodium salt of oxycellulose revealed excellent biocompatibility with cell line NCI-H441.
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