Synthesis of Surface-Charged IGF-1 Loaded PLGA Nanoparticles and Assess Dual Antimicrobial and Osteogenic Effects for Peri- Implant Bone Health: An In-Vitro Study.

Purpose: To develop Insulin-like Growth Factor-1 (IGF-1)-loaded poly (lactic-co-glycolic acid)(PLGA) nanoparticles (NPs) with altered surface charges (cationic, anionic, and neutral) and evaluate their dual antimicrobial and osteogenic potential in vitro.

Material and methods: IGF-1-loaded NPs were synthesized via solvent evaporation, characterized for size, charge, encapsulation efficiency, and release kinetics, and tested against peri-implant pathogens (Tannerella forsythia, Fusobacterium nucleatum, Prevotella intermedia, Porphyromonas gingivalis, Streptococcus mutans, and Staphylococcus aureus). The osteogenic potential was assessed using MG-63 (osteoblast-like) and U937 (osteoclast precursor) cell lines via MTT, ALP, and TRAP assays. Statistical analyses were performed using regression and ANOVA (P <.05).

Results: The NPs displayed spherical morphology with sizes ranging from 74.7 ± 2.2 nm to 151.7 ± 1.3 nm confirmed with SEM and zeta potentials from -15.6 ± 0.24 mV to +29.8 ± 1.4 mV. Encapsulation efficiencies were 66-75%, with sustained IGF-1 release of 64-67% over 21 days. Cationic NPs showed the strongest antimicrobial efficacy (Minimum Inhibitory Concentration (MIC): 378-756 ng/mL for secondary pathogens, 1512 ng/mL for primary pathogens), while neutral NPs demonstrated superior osteogenic activity, significantly enhancing MG-63 proliferation and ALP activity. Anionic NPs provided a broader antimicrobial spectrum but required higher concentrations for bactericidal effects.

Conclusions: Surface-modified IGF-1 loaded PLGA NPs achieved a dual therapeutic effect, combining potent antibacterial activity and enhanced osteogenesis. These findings support their potential as a non-antibiotic strategy for peri-implantitis management and bone regeneration.

Clinical implications: Modulating the charge potential of implant graft materials enhances both antibacterial activity against peri- implant pathogens and osteogenic efficiency, promoting bone regeneration and improving peri-implant health.