Synergistic Effect of Thermoresponsive and Photocuring Methacrylated Chitosan-Based Hybrid Hydrogels for Medical Applications

Abstract

The thermoresponsive drug-loaded hydrogels have attracted widespread interest in the field of medical applications due to their ease of delivery to structurally complex tissue defects. However, drug-resistant infections remain a challenge, which has prompted the development of new non-antibiotic hydrogels. To this end, we prepared chitosan-methacrylate (CTSMA)/gelatin (GEL) thermoresponsive hydrogels and added natural phenolic compounds, including tannic acid, gallic acid, and pyrogallol, to improve the efficacy of hydrogels. This hybrid hydrogel imparted initial crosslinking at physiological temperature, followed by photocuring to further provide a mechanically robust structure. Rheological analysis, tensile strength, antibacterial activity against E. coli, S. aureus, P. gingivalis, and S. mutans, and L929 cytotoxicity were evaluated. The experimental results showed that the hybrid hydrogel with CTSMA/GEL ratio of 5/1 and tannic acid additive had a promising gelation temperature of about 37 °C. The presence of phenolic compounds not only significantly (p < 0.05) enhanced cell viability, but also increased the tensile strength of CTSMA/GEL hybrid hydrogels. Moreover, the hydrogel containing tannic acid revealed potent antibacterial efficacy against four microorganisms. It was concluded that the hybrid hydrogel containing tannic acid could be a potential composite material for medical applications.

Carvacrol Encapsulation in Chitosan–Carboxymethylcellulose–Alginate Nanocarriers for Postharvest Tomato Protection

“…The second endotherm, appearing as a shoulder at 202 • C, bears resemblance to an effect observed around 193 • C for COS-TPP beads [36]. The third endotherm, at 220 • C, aligns with an effect previously documented for COS-MA [37]. Regarding the fourth endotherm at 236 • C, it is conceivable that it corresponds to the boiling point of carvacrol (241 • C).…”

In vitro cytotoxicity and antibacterial activity of hypochlorous acid antimicrobial agent

“…The former is the classical type of CFU assay, and the latter is used for real-time and repeated monitoring of bacterial viability. 27 , 45 The alamarBlue assay is much less labor intensive. It allows the estimation of the number of viable bacteria by the redox reaction between the indicator dye and metabolically active bacteria, 42 which is proportional to the maximum absorbance at 570 nm.…”

“…In addition to conventional counting, the antimicrobial ability of various test agents against bacterial species was also examined using the alamarBlue assay. 27 After removing the broth from the 96-well plate, 100 μL of test reagents was added to the bacterial sample for 1 or 10 min. After treatment, a 1:10 solution of alamarBlue (Invitrogen, Grand Island, NY, USA) to broth was added to each well and incubated at 37 °C for 10 min.…”

“…The bacteriostatic ratio (%) was calculated based on the absorbance. 27 Each value represented the average of three measurements.…”