Lysozyme-dequalinium encapsulation in a Zn–Fe LDH–chia seed matrix for enhanced antimicrobial dental therapeutics

Abstract

This study developed a lysozyme–dequalinium chloride-loaded Zn–Fe layered double hydroxide (LDH)–chia seed mucilage matrix for enhanced antimicrobial efficacy and sustained drug delivery. The optimized formulation (15% w/v Zn–Fe LDH–chia seed hybrid) achieved encapsulation efficiencies of 93.30 ± 1.92% (lysozyme) and 88.74 ± 1.71% (dequalinium), with a particle size of 153.77 ± 5.79 nm, PDI of 0.18, and zeta potential of +26.44 ± 1.21 mV, ensuring stability and mucoadhesion. Surface morphology, structure, drug loading, and thermostability were confirmed using various techniques. In vitro release studies showed sustained drug release over 24 h. Antimicrobial assays demonstrated inhibition zones against S. mutans (24.33 ± 2.03 mm), S. aureus (14.67 ± 0.88 mm), S. sobrinus (11.45 ± 0.887 mm), and K. pneumoniae (20.33 ± 2.03 mm). MIC/MBC analysis indicated high susceptibility of K. pneumoniae (MIC = 13.00 ± 2.60 μg mL⁻¹, MBC = 20.83 ± 5.23 μg mL⁻¹, P < 0.001) and S. mutans (MIC = 15.60 ± 1.05 μg mL⁻¹, MBC = 26.07 ± 5.23 μg mL⁻¹, P < 0.01), with S. sobrinus showing moderate sensitivity (MIC = 49.66 ± 4.32 μg mL⁻¹, MBC = 72.93 ± 6.43 μg mL⁻¹). MBC/MIC ratios below 4 confirmed bactericidal action. The formulation reduced S. mutans biofilm formation by 90.1 ± 1.2% at the highest tested concentration. Cytotoxicity evaluation showed a CC50 of 306.6 μg mL⁻¹, demonstrating improved cytocompatibility compared to the free components.