IADR Abstract Archives
Charge-Modified Nanoemulsions for Targeted Carvacrol Delivery in Interkingdom Biofilms
Objectives: Biofilms, intricate microbial communities embedded in extracellular polymeric substance matrices, posing significant challenges in treating infections, particularly interkingdom biofilms prevalent in the oral environment. While combining antibiotics and antifungals can enhance treatment, challenges like drug penetration and antimicrobial resistance persist. This study aims to investigate how the surface charge of nanoemulsions (NEs) loaded with carvacrol—an FDA-approved essential oil with antifungal and antibacterial properties—affects penetration and therapeutic efficacy against interkingdom biofilms.
Methods: Two distinct NEs were fabricated: 1) positively charged NEs with cationic guanidinium group (GMT-NE) and 2) negatively charged NEs with anionic carboxylate groups (CMT-NE). Dynamic light scattering (DLS), transmission electron microscopy and zeta potential were used to characterize the fabrication of polymers. Colloidal stability of NEs in human saliva was monitored via DLS. High-resolution confocal microscopy and computational analysis were employed to evaluate penetration capabilities, with Nile red encapsulated in NEs for dynamic tracking within the three-dimensional (3D) architecture of biofilms. Antibiofilm efficacy was assessed by measuring cell viability within interkingdom biofilms after different treatment durations. Biocompatibility was further evaluated using 3D murine oral mucosa cultures.
Results: Both NEs exhibited a consistent hydrodynamic size (~250 nm) and distinct zeta potentials (+25 mV for GMT-NE, -33 mV for CMT-NE), confirming successful fabrication with discrete surface charge attributes. Fluorescent labeling and spatial-temporal dynamics analysis showed accelerated diffusion of carvacrol with positively charged GMT-NEs compared to the CMT-NE analog, yielding a robust antimicrobial effect with 99.99 % killing for both species and marked reductions in bacterial cell viability compared to CMT-NE (~4-log reduction). Additionally, the 3D tissue cultures affirmed the biocompatibility of both NEs validating their potential for safe application in antibiofilm treatments.
Conclusions: Insights into NEs surface charge interactions with interkingdom biofilms are crucial for developing strategies to address complex oral infections involving bacteria and fungi.
Methods: Two distinct NEs were fabricated: 1) positively charged NEs with cationic guanidinium group (GMT-NE) and 2) negatively charged NEs with anionic carboxylate groups (CMT-NE). Dynamic light scattering (DLS), transmission electron microscopy and zeta potential were used to characterize the fabrication of polymers. Colloidal stability of NEs in human saliva was monitored via DLS. High-resolution confocal microscopy and computational analysis were employed to evaluate penetration capabilities, with Nile red encapsulated in NEs for dynamic tracking within the three-dimensional (3D) architecture of biofilms. Antibiofilm efficacy was assessed by measuring cell viability within interkingdom biofilms after different treatment durations. Biocompatibility was further evaluated using 3D murine oral mucosa cultures.
Results: Both NEs exhibited a consistent hydrodynamic size (~250 nm) and distinct zeta potentials (+25 mV for GMT-NE, -33 mV for CMT-NE), confirming successful fabrication with discrete surface charge attributes. Fluorescent labeling and spatial-temporal dynamics analysis showed accelerated diffusion of carvacrol with positively charged GMT-NEs compared to the CMT-NE analog, yielding a robust antimicrobial effect with 99.99 % killing for both species and marked reductions in bacterial cell viability compared to CMT-NE (~4-log reduction). Additionally, the 3D tissue cultures affirmed the biocompatibility of both NEs validating their potential for safe application in antibiofilm treatments.
Conclusions: Insights into NEs surface charge interactions with interkingdom biofilms are crucial for developing strategies to address complex oral infections involving bacteria and fungi.