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

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. <i>In vitro</i> release studies showed sustained drug release over 24 h. Antimicrobial assays demonstrated inhibition zones against <i>S. mutans</i> (24.33 ± 2.03 mm), <i>S. aureus</i> (14.67 ± 0.88 mm), <i>S. sobrinus</i> (11.45 ± 0.887 mm), and <i>K. pneumoniae</i> (20.33 ± 2.03 mm). MIC/MBC analysis indicated high susceptibility of <i>K. pneumoniae</i> (MIC = 13.00 ± 2.60 μg mL^-1, MBC = 20.83 ± 5.23 μg mL^-1, <i>P</i> < 0.001) and <i>S. mutans</i> (MIC = 15.60 ± 1.05 μg mL^-1, MBC = 26.07 ± 5.23 μg mL^-1, <i>P</i> < 0.01), with <i>S. sobrinus</i> 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 <i>S. mutans</i> 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.