Preparation of Conotoxin-Encapsulated Chitosan Nanoparticles and Evaluation of Their Skin Permeability

μ-Conotoxin CnIIIC (conotoxin, CTX)-loaded chitosan nanoparticles (CTX-NPs) were prepared using the ionic cross-linking method. The CTX-NPs were spherical and well with a polydispersity index of 0.292 ± 0.039, drug loading efficiency of 25.9 ± 1.2%, and encapsulation efficiency of 95.6 ± 1.3%. In vitro release studies showed that the release behavior of CTX-NPs in a pH 5.0 acetate buffer followed zero-order kinetics. In vitro transdermal experiments using Franz diffusion cells mounted with mouse abdominal skin demonstrated that the cumulative intradermal deposition amount of CTX per unit area in 8 h (D₈) and permeability coefficient (P_f) of CTX loaded on CTX-NPs were 2.30- and 7.71-times that of the CTX solution. In vivo transdermal experiments in mice showed that the amount of CTX deposited in the skin after 8 h of CTX saline administration was significantly lower than that of CTX deposited in the skin after administration of CTX-NPs. In vitro fluorescence labeling transdermal studies through Franz diffusion cells mounted with mouse abdominal skin indicated that CTX-NPs aggregated at hair follicles. Skin irritation tests in mice indicated that the irritation due to CTX-NPs was negligible. The cytotoxicity experiment showed that the viability of Balb/c 3T3 cells with CTX-NPs containing 230 μg/mL (0.08 μM) CTX was greater than 75%. CTX-NPs increase intradermal deposition of CTX by accumulating in hair follicles, which has positive implications for transdermal penetration of CTX.

State of the Art of Hydrogel Wound Dressings Developed by Ionizing Radiation

The development of an ideal hydrogel wound dressing with excellent characteristics is currently a significant demand in wound therapy. The ideal hydrogel wound dressing must provide a moist environment between the wound and the dressing, promote wound healing, absorb excess exudate and toxins, be completely sterile, and not adhere to the wound. The evolution and current status of research on hydrogel wound dressings obtained exclusively through production by ionizing radiation are discussed in this paper review, along with the preparation methods, properties, standard characterization techniques, and their applications in wound dressing. First, we described the methods for synthesizing hydrogel wound dressings with ionizing radiation. Then, standard methods of characterization of hydrogel wound dressings such as gel fraction, swelling degree, sol-gel analysis, rheological properties, morphology, moisture retention capability, and water vapor transmission rate have been investigated. In the end, specific attention was paid to the drug release, antibacterial performance, and cytotoxicity of hydrogels. Moreover, the application of hydrogel in regenerative medicine as wound healing dressing was covered.

Investigation on pH-switchable (itaconic acid/ethylene glycol/acrylic acid) based polymeric biocompatible hydrogel

A new variety of pH-sensitive polymeric hydrogels (IAE) have been developed and evaluated as biocompatible hydrogels using synergetic combinations of itaconic acid (IA), acrylic acid (AA), and ethylene glycol (EG) in water medium by free radical polymerization.

Fabrication of oxidized alginate-gelatin-BCP hydrogels and evaluation of the microstructure, material properties and biocompatibility for bone tissue regeneration

Composite hydrogel systems consisting of oxidized alginate, gelatin, and biphasic calcium phosphate were fabricated by the Schiff-base reaction and the effect of oxidation of alginate on the microstructure, material properties, and biocompatibility were evaluated. Alginate was modified by oxidizing the attached −OH groups to a −CHO group to facilitate interactions with the −NH2 groups of gelatin. The increased interactions between the functional groups had several effects on the materials properties, physical behaviors, and bio-compatibility. A higher degree of oxidation and thereby a higher extent of crosslinking between the −CHO and −NH2 groups resulted in an increase in water uptake and compressive strength, which was associated with a decrease in porosity, gelation time, bio-degradation rate, and to a smaller degree, biocompatibility. The hydrogel structure was highly porous and showed unique channel zed morphology with an extensive branching of the channels. The channels were not continuous and were divided into multiple segments by thin separators that were 5 µm thick and branched off of the 10–25 µm thick frame. The pores in the hydrogel system were interconnected and the porosity ranged from 44.45 to 67.89% with a pore size ranging from 100 to 300 µm. The compressive stress failure of the wet hydrogel was at 12.0 ± 1.2 MPa when the degree of alginate oxidation was 66.6%. The biocompatibility of the hydrogel system was excellent, although it was slightly lowered by oxidation. These hydrogels are promising biomaterials for bone regeneration with adjustable gelation and bio-degradation time, good mechanical strength, and excellent bio-compatibility.