Over the years, an increase in mass plastic production has caused growing concerns about the adverse effects that plastic nanoparticles (NPs) in the environment may have on human health. There are many knowledge gaps regarding the effects that NPs have on human health. Accurate studies prove challenging due to the hurdles in obtaining reliable model particles, performing accurate in vitro toxicology assessments, and visualizing results accurately. Numerous studies published in peer-reviewed literature have used commercially available NPs to represent environmental nanoplastic pollution. The commercial NPs with fluorescent tags were often used since they are easy to be monitored in cellular and organismal studies. However, the legitimacy of these commercial NP products has been questioned due to concerns about surface modifications altering interactions at the nano-bio interfaces, and the possibility that surface-bound fluorophores may detach and result in optical artifacts. Additionally, polystyrene is not the only polymer that should be investigated. We synthesized an orange, fluorescent organic dye and incorporated the dye into PMMA NPs to investigate skin cell uptake and in vivo biodistribution in a fish embryo model. We also compare the uptake results with that of the commonly used polystyrene particles and discuss possible mechanisms of uptake. Results revealed that 1) PMMA NPs can pass into embryos and potentially accumulate in larval bodies, and 2) commercially available sulfate-modified NPs and PMMA NPs accumulate similarly in fluorescently labeled fibroblast cells, however, PMMA NPs accumulate more localized intracellularly.

Periodontal diseases are prevalent worldwide and are linked to numerous other health conditions due to dysbiosis and chronic inflammatory state. Most periodontal diseases are caused by pathogenic bacteria that colonize dental tissues in the form of biofilm. Eradication of bacterial biofilms can be difficult to achieve due to the complex architecture of the teeth and gums which complicates the removal. Orthodontic wires and dental devices introduce additional hurdles to the adequate removal of biofilms by traditional methods since mechanical disruption via direct contact with toothbrush bristles, floss, and abrasive toothpaste is limited. Magnetically activated nanoparticles (NPs), specifically iron oxide nanoparticles (IONPs) that can be functionalized as antimicrobial particles and remotely controlled by magnetic fields, are of interest for oral biofilm eradication. We present data in multi-species bacterial cultures, established biofilms, human gingival keratinocytes, and human gingival fibroblast cells alone and in the presence of multispecies biofilm co-cultures to determine the safest, most efficacious IONP size ranges and treatment concentrations of active magnetic NPs for removal of dental biofilms. We report enhanced efficacy for IONPs coated with alginate vs. dextran, and small sizes (~8 nm vs. >20 nm in size) appear to exhibit enhanced antimicrobial efficacy. Human gingival keratinocyte (TIGK) cells in co-culture with treated and untreated multispecies biofilms in an in-vitro periodontitis model also exhibited a trend of reduced inflammatory markers in wells with IONP-treated biofilms.