Nano-graphene oxide incorporated into PMMA resin to prevent microbial adhesion

• Published in: Dental materials 2018-04, Vol.34 (4), p.e63-e72
• Main Authors: Lee, Jung-Hwan, Jo, Jeong-Ki, Kim, Dong-Ae, Patel, Kapil Dev, Kim, Hae-Won, Lee, Hae-Hyoung
• Format: Article
• Language: English
• Subjects: Acrylic Resins - chemistry; Candida albicans; Cell Adhesion - drug effects; Dental Materials - chemistry; Dentistry; Elastic Modulus; Escherichia coli; Flexural Strength; Graphene oxide nanoparticle; Graphite - chemistry; Hardness; Humans; Hydrophilicity; Hydrophobic and Hydrophilic Interactions; Keratinocytes - drug effects; Materials Testing; Microscopy, Electron; Nanoparticles - chemistry; Non-thermal oxygen plasma; Oxides - chemistry; PMMA; Polymethyl Methacrylate - chemistry; Saliva, Artificial; Staphylococcus aureus; Streptococcus mutans; Surface Properties; Sustained antimicrobial-adhesive effect
• ISSN: 0109-5641; 1879-0097
• DOI: 10.1016/j.dental.2018.01.019

[Display omitted] •Polymethyl methacrylate (PMMA) incorporating nano-sized graphene oxide (nGO) led to improved mechanical properties.•PMMA incorporating nGO exhibited an anti-adhesive effect against microbial species in artificial saliva.•An increase in hydrophilicity was considered a possible mechanism of the antimicrobial-adhesive effects of nGO-PMMA.•A sustained antimicrobial-adhesive effect was observed for up to 28 days. Although polymethyl methacrylate (PMMA) is widely used as a dental material, a major challenge of using this substance is its poor antimicrobial (anti-adhesion) effects, which increase oral infections. Here, graphene-oxide nanosheets (nGO) were incorporated into PMMA to introduce sustained antimicrobial-adhesive effects by increasing the hydrophilicity of PMMA. After characterizing nGO and nGO-incorporated PMMA (up to 2wt%) in terms of morphology and surface characteristics, 3-point flexural strength and hardness were evaluated. The anti-adhesive effects were determined for 4 different microbial species with experimental specimens and the underlying anti-adhesive mechanism was investigated by a non-thermal oxygen plasma treatment. Sustained antimicrobial-adhesive effects were characterized with incubation in artificial saliva for up to 28 days. The typical nanosheet morphology was observed for nGO. Incorporating nGO into PMMA roughened its surface and increased its hydrophilicity without compromising flexural strength or surface hardness. An anti-adhesive effect after 1h of exposure to microbial species in artificial saliva was observed in nGO-incorporated specimens, which accelerated with increasing levels of nGO without significant cytotoxicity to oral keratinocytes. Plasma treatment of native PMMA demonstrated that the antimicrobial-adhesive effects of nGO incorporation were at least partially due to increased hydrophilicity, not changes in the surface roughness. A sustained antimicrobial-adhesive property against Candida albicans was observed in 2% nGO for up to 28 days. The presence of sustained anti-adhesion properties in nGO-incorporated PMMA without loading any antimicrobial drugs suggests the potential usefulness of this compound as a promising antimicrobial dental material for dentures, orthodontic devices and provisional restorative materials.