A novel CNC-ZIF-8 nanocomposite exhibits potent antibiofilm activity against cariogenic Streptococcus mutans

Oral biofilms are key contributors to the development of dental caries and various periodontal diseases. Streptococcus mutans is a primary bacterium responsible for causing dental caries. Dental implants are frequently used to replace missing teeth, but biofilm accumulation on these implants is a major factor in implant failure. In the realm of dentistry, metal organic framework (MOFs) has shown potential in addressing the prevalent issue of dental caries, commonly known as tooth decay. ZIF-8 provides pH-responsive Zn²⁺ release in acidic environments typical of dental caries. Carbon nanocrystals (CNC) and gold nanoparticles (AuNPs) are biocompatible nanoparticles that generate reactive oxygen species (ROS) under light and enhance antibacterial effects. Together, they offer targeted, dual-action antibacterial power. Cariogenic bacteria or their metabolic by products can be selectively captured from saliva or dental plaque using functionalized MOFs (Au/ZIF-8 and CNCs/ZIF-8). This investigation explores the antibacterial efficacy of ZIF-8-derived nanocomposites (Au-Np/ZIF-8 and CNC/ZIF-8) in neutralizing the decay-promoting properties of Streptococcus mutans. Fundamental virulence characteristics of S. mutans biofilm architecture includes metabolic acid production, environmental acid resistance, and exopolysaccharide (EPS) matrix formation. In-vitro investigations demonstrated a reduction in growth of biofilm by 64.31% (Au/ZIF-8) and 68% (CNC/ZIF-8). The results showed that treating with sub-MIC concentrations of CNC/ZIF-8 reduced EPS formation by over 51%. The present investigation represents the inaugural assessment of CNC/ZIF-8 nanocomposites as potential surface modification materials for dental implant applications. Acrylic substrates treated with CNCs/ZIF-8 demonstrated substantial inhibition of S. mutans biofilm (95% reduction). Its biocompatible properties make this nanocomposite ideal for coating implants.