Title : Biopolymer systems crosslinked with citric acid for the controlled release of curcumin with antimicrobial properties
Abstract:
Increasing antimicrobial resistance represents a major challenge for the treatment of bacterial infections, particularly those associated with the skin and soft tissues. In this context, the development of biosustainable biomaterials with antimicrobial properties has emerged as a promising strategy for designing new therapeutic alternatives. Turmeric (Curcuma longa) has attracted increasing scientific interest due to its multiple biological properties. This rhizome, widely used in traditional medicine and the food industry, contains curcumin as its main bioactive compound, a polyphenol recognized for its antimicrobial, anti-inflammatory, and antioxidant activities. However, its clinical application is limited by low water solubility, poor bioavailability, and rapid degradation, which have encouraged the development of encapsulation systems to improve its stability and biological efficacy.
In this context, the present study aimed to develop eco-friendly materials based on biopolymers capable of acting as controlled-release systems for curcumin with antimicrobial activity. For this purpose, starch films incorporated with poloxamer P188 nanostructures were synthesized using citric acid as a crosslinking agent for the polymeric matrix. This system enabled the encapsulation of curcumin at different concentrations to optimize its stability and release profile. The structural and physicochemical characterization of the materials was performed using Fourier transform infrared spectroscopy (FTIR), contact angle measurements, as well as swelling and solubility assays in different aqueous solutions. Additionally, time-dependent curcumin release studies were conducted to evaluate the release profile of the developed system. Antimicrobial activity was evaluated using the disk diffusion assay against Gram-positive and Gram-negative bacteria, including Staphylococcus aureus and Pseudomonas aeruginosa, respectively. The results demonstrated a significant antimicrobial effect, with higher activity against Gram-positive bacteria, reaching an inhibition halo of 23 mm, as well as a statistically significant reduction in bacterial growth compared to the negative control, achieving nearly 80% inhibition. On the other hand, it was observed that the presence of curcumin decreased the water absorption capacity (WAC) of the materials. Likewise, the system exhibited controlled curcumin release, reaching up to 97% at 144 h. Overall, these findings suggest that eco-friendly biomaterials based on starch and poloxamer, crosslinked with citric acid, represent a promising alternative for enhancing the antimicrobial efficacy of natural compounds such as curcumin, contributing to the development of sustainable strategies for the treatment of bacterial infections.
