Biodegradability, antimicrobial activity and properties of PVA/PVP hydrogels prepared by γ-irradiation. J Polym Res Taiwan
Polyvinyl alcohol/polyvinyl pyrrolidone (PVA/PVP) hydrogel has been prepared by using γ-irradiation technique. In the present
study the conclusion on miscibility of PVA/PVP blends, confirmed qualitatively and quantitatively by using Fourier transform
infrared spectroscopy and differential scanning calorimetry, respectively. PVA and PVP are found to form a thermodynamically
miscible pair. The physical properties such as gel fraction and water absorption performance of the prepared hydrogels were
measured, it was found that the gel fraction increases with increasing irradiation dose while the swelling of PVA/PVP blended
hydrogels nearly tends to increase with increasing PVP content and reduced with enhanced irradiation doses. The hydrogel pore
structure of various PVA/PVP compositions were tested with SEM. Ability of PVA/PVP hydrogels to absorb and release antimicrobial
compounds was tested using amoxicillin as an antibacterial and ketoconazole as an antifungal. Antimicrobial activity of PVA/PVP
hydrogels was examined using four bacteria, and four fungi. No antibacterial or antifungal activities of non-loaded PVA/PVP
of various compositions were detected while the loading ones found to have antimicrobial activity. Results showed resistance
of Pseudomonas aeruginosa and Candida albicans to PVA/PVP, while Bacillus subtilis was very sensitive. Biodegradation of PVA/PVP hydrogels was investigated by burial method in two types of local soils (clay
and sandy soils). The highest degradation rate was found to be achieved using clay soil. Also, effect of irradiation dose
on its biodegradability was tested. The results showed that the radiation prepared PVA/PVP hydrogels can be use as biomaterials.
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- "PVP is another hydrogel that has been used for a variety of biomedical applications due to its good biocompatibility and hydrophilic ability properties  . The incorporation of PVP into PVA is expected to significantly decrease degradation and stabilize the polymer network and the mechanical properties of pure PVA hydrogels through hydrogen bonding interactions between the carbonyl group on PVP and the hydroxyl group along PVA chain . Leone et al.  has demonstrated the biocompatibility of PVA/PVP hydrogel. "
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- "Particularly in the case of biomaterial surfaces, densely grafted polymeric layers ( " polymer brushes " ) are frequently applied to reduce protein adsorption , bacteria adhesion  or prevent cellesurface interactions . Poly (ethylene glycol) (PEG) [21e23] represents the gold standard in this respect but other polymers such as polyacrylamide (PAAM) , poly(vinyl pyrrolidone) (PVP)  and peptidomimetics  as well as poly(2-methyl-2-oxazoline) (PMOXA)   have been shown to be similarly effective. Polycationic poly(L-lysine)-graft-poly(ethylene glycol) (PLL-g- PEG)  and poly(L-lysine)-graft-poly(2-methyl-2-oxazoline) (PLLg-PMOXA)  with different polymeric architecture have been previously studied for the preparation of ultrathin films by electrostatically driven assembly on negatively charged metal surfaces (e.g., titanium oxide, niobium oxide and tissue culture polystyrene). "
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ABSTRACT: Surface platforms were engineered from poly(L-lysine)-graft-poly(2-methyl-2-oxazoline) (PLL-g-PMOXA) copolymers to study the mechanisms involved in the non-specific adhesion of Escherichia coli (E. coli) bacteria. Copolymers with three different grafting densities α (PMOXA chains/Lysine residue of 0.09, 0.33 and 0.56) were synthesized and assembled on niobia (Nb₂O₅) surfaces. PLL-modified and bare niobia surfaces served as controls. To evaluate the impact of fimbriae expression on the bacterial adhesion, the surfaces were exposed to genetically engineered E. coli strains either lacking, or constitutively expressing type 1 fimbriae. The bacterial adhesion was strongly influenced by the presence of bacterial fimbriae. Non-fimbriated bacteria behaved like hard, charged particles whose adhesion was dependent on surface charge and ionic strength of the media. In contrast, bacteria expressing type 1 fimbriae adhered to the substrates independent of surface charge and ionic strength, and adhesion was mediated by non-specific van der Waals and hydrophobic interactions of the proteins at the fimbrial tip. Adsorbed polymer mass, average surface density of the PMOXA chains, and thickness of the copolymer films were quantified by optical waveguide lightmode spectroscopy (OWLS) and variable-angle spectroscopic ellipsometry (VASE), whereas the lateral homogeneity was probed by time-of-flight secondary ion mass spectrometry (ToF-SIMS). Streaming current measurements provided information on the charge formation of the polymer-coated and the bare niobia surfaces. The adhesion of both bacterial strains could be efficiently inhibited by the copolymer film only with a grafting density of 0.33 characterized by the highest PMOXA chain surface density and a surface potential close to zero.
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ABSTRACT: 60Co γ rays induced styrene emulsion polymerizations were carried out with sodium undec-10-enoate (UDNa) as emulsifier at room temperature and the different kinetics was discussed. The influence of absorbed dose rate, monomer concentration and emulsifier concentration on kinetics and latex particles was studied. The polymerization kinetics relation was found as R
, maximum polymerization rate; D, absorbed dose rate; M, monomer concentration; E, emulsifier concentration). The particles’ diameter increases and particle size distribution (PSD) becomes narrower with the decrease of absorbed dose rate and increase of monomer content. The effect of UDNa content on particles’ diameter and particle size distribution is the same as that of emulsifier in conventional emulsion system. This type of emulsion polymerization can easily form monodisperse particles.
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