Xylan-Based Cross-Linked Hydrogel for Photodynamic Antimicrobial Chemotherapy

Area of Science:

• Biomaterials Science
• Photochemistry
• Antimicrobial Therapy

Background:

• Photodynamic antimicrobial chemotherapy (PACT) shows promise against multidrug-resistant bacteria.
• Existing photosensitizers face challenges like self-quenching, poor solubility, and lack of selectivity.
• Hydrogels offer a potential solution to overcome these limitations.

Purpose of the Study:

• To synthesize a cross-linked hydrogel from beech xylan for PACT applications.
• To encapsulate a hydrophilic photosensitizer (TMPyP) within the xylan hydrogel.
• To evaluate the hydrogel's properties and its photocytotoxic efficacy against bacterial strains.

Main Methods:

• Synthesis of a cross-linked hydrogel from beech xylan.
• Characterization of hydrogel properties: swelling ratio, porous structure, and mechanical integrity.
• Encapsulation of 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin tetraiodide (TMPyP) into the hydrogel.
• Assessment of TMPyP release kinetics and photocytotoxic effects against bacterial strains (P. aeruginosa, E. coli, S. aureus, B. cereus).

Main Results:

• The synthesized xylan hydrogel exhibited a high swelling ratio (up to 62), a porous structure, and good mechanical integrity.
• Encapsulated TMPyP demonstrated prolonged release over 24 hours, reaching 100% cumulative release.
• TMPyP-loaded hydrogel showed significant photocytotoxic activity against P. aeruginosa, E. coli, S. aureus, and B. cereus, with no observed dark toxicity.

Conclusions:

• Beech xylan can be readily fabricated into a hydrogel suitable for encapsulating photosensitizers.
• The developed hydrogel system enables sustained release of photosensitizers, enhancing PACT efficacy.
• This xylan-based hydrogel represents a promising platform for developing advanced photodynamic antimicrobial chemotherapy strategies against resistant bacteria.