Zeolite/Chitosan/Gelatin Films: Preparation, Supercritical CO₂ Processing, Characterization, and Bioactivity

Abstract

Chitosan/gelatin and chitosan/gelatin/zeolite films prepared by solvent casting method are impregnated with a mixture of thymol and carvacrol using a green solvent, supercritical carbon dioxide at 35 °C and 30 MPa, during 18 h. Proposed method enables preparation of biocompatible and biodegradable blends with strong antioxidant and antibacterial activity, whereby amounts of loaded thymol/carvacrol (TC) mixture are in the range from 3.3% to 6%. After initial burst release, both types of films exhibit gradual release of bioactive compounds, with around 72% and 96% of impregnated TC mixture released in water and phosphate buffered saline solution (pH 7.4) during tested period of 10 days, respectively. Results of water vapor transmission rate (>76 g m −2 day −1 ) confirm that prepared composites are suitable for wound dressing application. Thermal analysis shows superior properties of prepared TC loaded films compared to control samples. In addition, mechanical and structural properties, as well as solubility and swelling behavior of the obtained films are investigated in detail.

Thymol@Natural Zeolite Nanohybrids for Chitosan/Polyvinyl-Alcohol-Based Hydrogels Applied as Active Pads

“…Conversely, the film materials containing zeolite alone did not exhibit significant antimicrobial efficacy. This finding aligns with those in the existing literature, which reports the lack of inherent antibacterial activity exhibited by zeolite itself [41,42].…”

“…Similarly, Pajnik et al (2022) [42] reported analogous findings regarding the antibacterial effects of zeolite/chitosan/gelatin films. They observed that the antibacterial effect of the films alone, without thymol or carvacrol impregnation, was insignificant.…”

One-step Preparation of Antibacterial Gelatin/Polycaprolactone Nanofibrous Janus Membranes for Efficient Hemostasis

“…The functional groups of the nanofibers were analyzed via FT-IR (Figure a). Absorption peaks at 1090and 805 cm –1 assigned to Al–O and Si–O groups could be seen in the curves of Ze, Gel@Ze, and Gel@Ze@PDA, which were associated to the presence of zeolite. , The strong absorption peaks near 3420 cm –1 were identified as the −OH and −NH stretching of gelatin, and the absorption peaks at 1545 and 1240 cm –1 could be assigned to N–H/C–N stretching (amide II) and N–H bending (amide III), respectively. , It should be noted that no noticeable difference was found in the curves of Gel@Ze and Gel@Ze@PDA due to their similar characteristic peaks and low PDA content. Meanwhile, TG analysis also confirmed the presence of zeolite powders.…”

An overview on the application of supercritical carbon dioxide for the processing of pharmaceuticals

“…The unique properties of scCO2 and the environmental benefits of scCO2-assisted processes have led to a variety of its applications. ScCO2 processes on a laboratory scale are mostly used for (a) separation of bioactive extracts from plant material (4,6) to avoid the use of organic solvents and/or high temperatures (7), (b) supercritical drying to remove liquids from gels without a change in the wet gel matrix (8,9), (c) polymer impregnation with bioactive components (10,11), (d) both natural and synthetic textile dyeing (7), (e) modification/functionalization of inert inorganic solids (12), and (f) distribution of drugs into solid polymer matrices (13)(14)(15). In the field of polymeric processing, scCO2 can act as a plasticizer of semicrystalline and amorphous polymers and induce polymer foaming (16).…”