Comparison of Morphology and Cytotoxicity of Cellulose Composites with Nano- and Microhydroxyapatite for Bone Tissue Engineering

Scaffolds for bone tissue regeneration must be precisely designed as they support cell attachment, proliferation, differentiation and blood vessel in-growth. Moreover, the materials which are implanted in human body must be non-cytotoxic, absolutely harmless. In this work cellulose scaffolds with nanohydroxyapatite and microhydroxyapatite were prepared. The results obtained in this work revealed that the morphology of the scaffolds depended on the size of hydroxyapatite particles. The porosity of the scaffolds varied from 66 to 72%. The pores were interconnected with the average diameter 0.49 and 0.54 mm for scaffolds with nano- and microhydroxyapatite, respectively. Biocompatibility and potential toxicity of the experimental cellulose/hydroxyapatite scaffolds were tested. It was determined that the scaffolds containing nanohydroxyapatite particles showed slight cytotoxic effect

Comparison of Morphology and Cytotoxicity of Cellulose Composites with Nano- and Microhydroxyapatite for Bone Tissue Engineering

Scaffolds for bone tissue regeneration must be precisely designed as they support cell attachment, proliferation, differentiation and blood vessel in-growth. Moreover, the materials which are implanted in human body must be non-cytotoxic, absolutely harmless. In this work cellulose scaffolds with nanohydroxyapatite and microhydroxyapatite were prepared. The results obtained in this work revealed that the morphology of the scaffolds depended on the size of hydroxyapatite particles. The porosity of the scaffolds varied from 66 to 72%. The pores were interconnected with the average diameter 0.49 and 0.54 mm for scaffolds with nano- and microhydroxyapatite, respectively. Biocompatibility and potential toxicity of the experimental cellulose/hydroxyapatite scaffolds were tested. It was determined that the scaffolds containing nanohydroxyapatite particles showed slight cytotoxic effect

Sorption of poly(vinyl alcohol) and its cationic derivative on silica oxide: effect of charge

Adsorption of poly(vinyl alcohol)-based cationic polyelectrolyte (DEAE-PVA) as well as unmodified poly(vinyl alcohol) (PVA) onto silica oxide surface was studied by means of reflectometry. The study was focused on the effect of charge of polymer segments on their adsorption on silica oxide. The results showed that the adsorption rate depended on the polymer concentration and was significantly higher for polyelectrolyte than for unmodified PVA. The maximum adsorbed value at the same pH did not depend on polymer concentration. The adsorption of both polymers on silica oxide was highly affected by pH. To explain the reasons, the zeta potential of the silicagel surface as well as of the polymers was measured. The highest sorption of DEAE-PVA was reached at pH above 6 when the gel surface and DEAE-PVA were charged oppositely. It was presumed that the DEAE-PVA adsorption was strongly affected by the electrostatic interaction between dissociated silanols and amino groups of the polymer. The coated silica oxide surface was characterized by atomic force microscopy. The water contact angles showed that the coated surfaces were more hydrophilic and possessed better wetting abilities than the surface of uncoated silica oxid

Preparation of cellulose-based sponges for wound dressing and healing

For healing of chronic or burn wounds, polymeric sponges have been recently applied. Due to a high absorption capacity, noncitotoxicity and good swelling capabilities, for their production natural polymers are often used. In this study, macroporous regenerated cellulose was evaluated as a matrix for wound dressing materials. Active compounds, such as antibiotic neomycin and phenolic compound quercetin were immobilized in the cellulosic matrix aimed to promote wound healing process. Active compounds in the sponges were immobilized alone or with water-soluble hydroxyethylcellulose or carboxymethylcellulose. It was found that the way of preparation of sponges can affect their porosity, moisture absorption and drying rate. The best sponges for wound dressing materials were formed from freeze-dried macroporous regenerated cellulose in which was later immobilised hydroxyethylcellulose or carboxymethylcellulos with active compounds

Characterization of cellulose based sponges for wound dressings

Cellulose based sponges were developed by freeze-drying of regenerated cellulose gels and characterizedas a potential wound dressing. Morphological characteristics were analyzed by means of micro-computedtomography. The results showed that the porosity of the sponges reached 75%, the pores were inter-connected and their size ranged from 10 to 1200 m with a mean pore diameter of 750 m. Due tohydrophilicity of cellulose and high specific surface area (14.5 mm2/mm3) the sponges possess highsorption of simulated wound fluids (approx. 210%) and high water vapour transmission ability. Dif-ferent active compounds, such as polyphenols from Calendula officinalis or Chamomilla recutita extracts(1 day diffusion experiment), silver nanoparticles (1, 2 and 4 days diffusion experiments) were immo-bilized into the sponges in order to improve wound dressing performance. Release kinetics of silvernanoparticles and polyphenols from the sponges were investigated. The sponges incorporated with sil-ver, showed antibacterial activity against Staphylococcus epidermidis. Thus, these cellulose based spongesare promising wound dressing materials for fester and infected wounds