Wound dressing membranes based on immobilized Anisaldehyde onto (chitosan-GA-gelatin) copolymer: In-vitro and in-vivo evaluations.

Herein, wound dressing membranes based on covalently linked Chitosan (Ch) to Gelatin (GE) via Glutaraldehyde (GA) to have (Ch-GA-GE) copolymer have been developed. In addition, Anisaldehyde (An) was immobilized onto Ch-GA-GE to has An-(Ch-GA-GE) membrane. The changes of the Ch-GA-GE membranes wettability, from 26 ± 1.3° to 45.3 ± 2.27° of the An-(Ch-GA-GE) copolymer membrane, indicating the reduction of copolymers hydrophilicity. The thermal characterization was done using TGA and DSC, while the morphological analysis was done using SEM. The antibacterial properties were assessed against four bacterial strains (P. aeruginosa, S. aureus, Streptococcus, and E. coli). In-vitro evaluation of the fabricated membranes to be used as wound dressings was investigated by measuring their hemocompatibility, cytotoxicity, and biodegradability. Finally, the in-vivo assessment of the developed membranes to encourage skin regeneration was assessed utilizing adult Wistar albino rats. The results illustrated that the An-(Ch-GA-GE) copolymer membranes significantly enhanced the rat's full-thickness injuries, as monitored by reducing the wound region. Furthermore, histological analyses of the injuries covered with An-(Ch-GA-GE) membranes demonstrated a notable re-epithelialisation contrasted with wounds treated with the cotton gauze Ch-GA-GE membranes dressings proving the efficiency of Anisaldehyde. Those findings indicate that the An-(Ch-GA-GE) membrane has considerable potential for wound healing and skin regeneration.

Fabrication of biodegradable gelatin/chitosan/cinnamaldehyde crosslinked membranes for antibacterial wound dressing applications.

This study intends to fabricate new biodegradable and antimicrobial membranes based on crosslinked gelatin/chitosan biopolymers. Cinnamaldehyde was incorporated into membranes for boosting their antimicrobial activities. FTIR spectroscopy and electronic spectrum analysis were used to prove their chemical structures, while SEM and TGA analysis were applied to investigate the morphological changes and the thermal properties of the crosslinked membranes. Moreover, ion exchange capacity, wettability and mechanical analysis were also conducted to get more information about the physicochemical properties for the developed membranes. Four different types of bacteria have been used for studying the antibacterial activities of the crosslinked membranes (one gram-positive and three gram-negative bacteria). The results showed a significant augmentation in the inhibition percent with increasing cinnamaldehyde content in the membrane matrix. Besides, hemocompatibility, biodegradability, and cytotoxicity studies were performed and the findings emphasized that the as-fabricated biodegradable gelatin/chitosan/cinnamaldehyde membranes could be efficiently used as antibacterial dressers for ameliorating the wound healing.

In vitro displacement by rat serum of adsorbed radiolabeled poloxamer and poloxamine copolymers from model and biodegradable nanospheres.

Poloxamer 407 and poloxamine 908 have been used by many research groups to modify the surface of both model latex and biodegradable nanospheres, thereby producing nanospheres that have shown reduced protein adsorption in vitro and extended circulation times in vivo. A potential limitation of such systems is the desorption of the copolymer coating layer. We describe a two-stage process to radiolabel poloxamer 407 and poloxamine 908 that has facilitated an investigation into this potential desorption, in vitro. The first stage of the labeling procedure involved the substitution of the terminal hydroxyl groups in each poly(ethylene oxide) (PEO) chain of poloxamer 407 and poloxamine 908 with an amino group. The aminated copolymers were then radiolabeled with 125Iodine Bolton-Hunter reagent. The efficiency of labeling was calculated to be approximately 20% for the tetramine poloxamine 908 and approximately 33% for the diamine poloxamer 407. Remaining free amino groups were then either acetylated, using acetic anhydride, or left in the free amino form. Covalent linkage of the radiolabel to the copolymer was confirmed by nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy. The stability of the link between radiolabel and copolymer to hydrolysis was also confirmed; <4% loss of radiolabel occurred from poloxamine 908 after incubation in phosphate-buffered saline (PBS) at 37 degrees C for 8 days. The radiolabeled copolymers (with the free amino groups acetylated) were then used in experiments that have given the first direct evidence that adsorbed copolymers can be displaced by serum proteins in significant amounts from the surface of model and biodegradable nanospheres. The displacement was highly dependent on copolymer-nanosphere compatibility, with up to 78% of 125I tetramine poloxamine 908 being displaced from poly(lactide-co-glycolide) (PLGA) nanospheres in 24 h, compared with 20% displacement of 125I tetramine poloxamine 908 in 24 h from polystyrene nanospheres. These results have direct implication for the future design of drug delivery systems based on coated nanospheres.