Journal of Bioactive and Compatible Polymers

In this study, the single and synergistic effects of montmorillonite and curcumin-loaded chitosan microparticles incorporated onto the polylactic acid films were investigated on full-thickness excisional wounds of rats . The polylactic acid microfibrillated film was electrospun from a 10% (w/v) polylactic acid in chloroform solution. The curcumin-loaded chitosan microparticles were prepared via ionic gelation technique with high drug loading and encapsulation efficiency. The alkaline-treated polylactic acid films were assembled with positively charged chitosan as the first layer and the negatively charged montmorillonite (NC dressing), curcumin-loaded chitosan microparticles (CCM dressing), and their mixture (1:1 (v/v); NC/CCM dressing) as the second layer via layer-by-layer self-assembly technique. The montmorillonite incorporation increased the hydrophobicity and water vapor transmission rate of the CCM dressing but decreased its water-uptake capacity. The films showed good cytocompatibility to L929 fibroblastic cell line, and the in vivo wound-closure percentage result showed that CCM > NC > NC/CCM > sterile gauze. The overall result indicated that the montmorillonite and curcumin-loaded chitosan microparticles had no considerable positive synergistic effects onwound-healing.

Chitosan has been modified through the reaction of chitosan with 5-phenyl-1,3,4-oxadiazole-2-thiol (I); 5-amino-1,3,4-thiadiazole-2-thiol (II); and 5-(4 chlorophenyl)-1,3,4-thiadiazole-2-thiol (III). Fourier transform infrared spectroscopy spectra and ¹H-NMR demonstrated the interaction between 1,3,4-oxa(thia)diazoles and chitosan. The Gram-negative bacteria (Escherichia coli ATCC 8739, Aeromonas hydrophila, Shegilla sp.), Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis ATCC 6633), yeast (Candida albicans), and the filamentous fungi (Aspergillus niger) were used to examine the antimicrobial activity of the modified chitosan by well diffusion method. The results indicated that modified chitosan possess better inhibitory property than chitosan. Furthermore, in vivo study was performed on burned mouse model wound infection by S. aureus NCTC 6356. Modified chitosan improved antimicrobial efficacy against fatal burn infections in comparison with chitosan.

This study aimed to develop a recombinant human erythropoietin/aloe vera gel–releasing polyvinyl alcohol/chitosan wound dressing by wet-electrospinning method and investigate the synergistic effects of erythropoietin and aloe vera gel on the excisional wound healing. The polyvinyl alcohol/chitosan (4:1 (w/w)) solution was electrospun into an aloe vera gel–containing water coagulation bath and then coated with the recombinant human erythropoietin–loaded chitosan nanoparticles prepared via ionic gelation technique. The developed sponge-like film was able to release the erythropoietin and aloe vera gel for at least 7 and 1 days, respectively. The dressing was non-toxic to L929 fibroblastic cell line and non-adherent to the wound bed with the contact angle of 67.93° ± 2.31°. It also possessed the water-uptake capacity and water vapor transmission rate of 26.40% ± 3.37% and 2584.00 ± 144.67 g m⁻², respectively. The in vivo study demonstrated the synergistic wound-healing effects of aloe vera gel and erythropoietin on the full-thickness excisional wounds of Wistar rats. The erythropoietin/aloe vera gel–releasing dressing had significantly (n = 4, p < 0.005) higher wound closure (92.96% ± 10.09%) than the sterile gauze (73.89% ± 2.61%), as the control group, after 2 weeks. The differences observed between the wound closure percentages of the aloe vera gel–releasing dressing (85.93% ± 6.46%) and the erythropoietin/aloe vera gel–releasing dressing and control group were not statistically significant.

In this study, taurine (2-aminoethane sulfonic acid), an amino acid found in large amounts in most mammalian tissues, was incorporated with poly (ε-caprolactone) and gelatin in order to develop a drug-loaded composite wound dressing material. The composite mats from poly (ε-caprolactone)/gelatin (1:1 (w/w)) solution incorporated with 3%, 5%, and 10% (w/w) of taurine were produced by electrospinning. The electrospun mats were evaluated regarding their morphology, wettability, water uptake capacity, water vapor transmission rate, tensile strength, and cellular response with L929 cell line. The mat containing 5% of taurine was chosen as the optimum dressing for in vivo study on the full-thickness excisional wounds of Wistar rats. The results showed that after 2 weeks, the wounds treated with the taurine-loaded dressing achieved a significant closure to nearly 92% compared with the sterile gauze, as control, which showed nearly 68% of wound closure. The histological examination of the wounds revealed that the wounds treated with the taurine-loaded dressing had densely packed collagen fibers with parallel alignment. Whereas, the sterile gauze–treated wounds had loosely packed collagen fibers with an irregular arrangement. Our results provided evidence supporting the possible applicability of the taurine-loaded wound dressings for successful wound treatment.

Here, in this study, we have investigated the antibacterial activity and cytotoxicity of pegylated aminoglycosides (gentamicin, kanamycin, and neomycin). The antibacterial activity of pegylated aminoglycosides, prepared in two different ratios (1:1 and 1:2, aminoglycoside:polyethylene glycol), was determined against some common pathogens, namely, Gram-positive (Bacillus cereus, Staphylococcus aureus) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa), by zone of inhibition and minimum inhibitory concentration assays. The activity of pegylated aminoglycosides was found to be decreased as compared to their respective native aminoglycosides. Moreover, aminoglycoside:polyethylene glycol (1:1) derivatives showed much higher activity as compared to aminoglycoside:polyethylene glycol (1:2) derivatives, that is, an increase in the content of polyethylene glycol decreased the activity considerably. This decrease in antibacterial activity was found to be the most prominent in Gram-positive bacteria, S. aureus. On the other hand, pegylation significantly decreased the cytotoxicity as determined by hemolysis and MTT assays. These results advocate exploration of different types of crosslinkers consisting of a small degree of amphiphilicity, which could facilitate better interactions with the bacterial cell membranes and inhibit induction of bacterial resistance.

Injectable and temperature-sensitive hydrogels were synthesized for use as a tissue-adhesive material between dopamine end-capped Pluronic and CCDP-q-PDB (2-chloro-3′,4′-dihydroxyacetophenone-quaternized poly((dimethyl aminoethyl methacrylate)-co-(t-butylmethacrylate))). The mixture of dopamine end-capped Pluronic and CCDP-q-PDB exists in a viscous solution state at room temperature, but becomes a gel via in situ crosslinking at body temperature. The hydrogel structure was shown to be more stable than Pluronic F127 copolymers in aqueous solution. At a 14:8 wt% ratio of dopamine end-capped Pluronic to CCDP-q-PDB, the sol quickly transformed into a gel at body temperature and under physiological conditions (<10 s), showing excellent gel stability. To evaluate the tissue-adhesive properties, the temperature-sensitive crosslinked dopamine end-capped Pluronic CCDP-q-PDB hydrogels, which can be applied for drug delivery, tissue engineering, and for use as tissue adhesives, were tested using a universal testing machine.

The effects on cell adhesion induced by changes in the topography and chemistry of poly(2-hydroxyethyl methacrylate) hydrogel surfaces were investigated in vitro using the human corneal epithelial cell line, HCE-T. Poly(2-hydroxyethyl methacrylate) surfaces with a lotus-leaf-like topography and poly(2-hydroxyethyl methacrylate) surfaces with a flat topography, but functionalized with the cell-adhesive peptide sequence Arg–Gly–Asp, both enhanced attachment of HCE-T cells as compared to flat, non-functionalized poly(2-hydroxyethyl methacrylate) surfaces. However, the simultaneous existence on the same poly(2-hydroxyethyl methacrylate) surface of Arg–Gly–Asp motifs and of lotus-leaf-like topographical patterns led to an apparently antagonistic effect reflected in reduced cell attachment. The study provided additional evidence of the complexity of the cell–biomaterial interactions.

This study explores the suitability of the fish scale gelatin as an alternative for biomaterial for tissue engineering and regenerative medicine. In brief, collagen extracted from fish scales converted to gelatin with required bloom strength for its suitability for further modification with phenolic acids. Dihydroxy phenolic acid (caffeic acid) is tethered to the fish scale gelatin using carbodiimide chemistry. Characterization studies suggested and confirmed the change of the fish scale gelatin to phenolic acid modified gelatin. Further, physical, thermal, mechanical, biodegradable, and cytocompatible properties phenolic acid modified gelatin studied in detail. Results displayed that modification of fish scale gelatin with dihydroxy phenolic acid imparts mechanical, biodegradability, and cytocompatible properties as expected. Micro–computed tomography analysis of phenolic acid modified gelatin demonstrates the appreciable porous structures which facilitate the adherence and proliferation of cells. In conclusion, phenolic acid modified gelatin shows the suitability and also as an alternative to the existing synthetic and other natural materials for tissue engineering research.