Comparison of Antibacterial Adhesion When Salivary Pellicle Is Coated on Both Poly(2-hydroxyethyl-methacrylate)- and Polyethylene-glycol-methacrylate-grafted Poly(methyl methacrylate).

Bor-Shiunn Lee,Tien-Li Ma,Ta-Chin Wei,Che-Chen Chang,Yu-Jia Chen

doi:10.3390/ijms19092764

Abstract

Although poly(2-hydroxyethyl methacrylate) (pHEMA) and polyethylene glycol methacrylate (PEGMA) have been demonstrated to inhibit bacterial adhesion, no study has compared antibacterial adhesion when salivary pellicle is coated on polymethyl methacrylate (PMMA) grafted with pHEMA and on PMMA grafted with PEGMA. In this study, PMMA discs were fabricated from a commercial orthodontic acrylic resin system (Ortho-Jet). Attenuated total reflection-Fourier transform infrared spectra taken before and after grafting confirmed that pHEMA and PEGMA were successfully grafted on PMMA. Contact angle measurements revealed PMMA-pHEMA to be the most hydrophilic, followed by PMMA-PEGMA, and then by PMMA. Zeta potential analysis revealed the most negative surface charges on PMMA-PEGMA, followed by PMMA-pHEMA, and then by PMMA. Confocal laser scanning microscopy showed green fluorescence in the background, indicating images that influenced the accuracy of the quantification of live bacteria. Both the optical density value measured at 600 nm and single plate-serial dilution spotting showed that pHEMA was more effective than PEGMA against Escherichia coli and Streptococcus mutans, although the difference was not significant. Therefore, the grafting of pHEMA and PEGMA separately on PMMA is effective against bacterial adhesion, even after the grafted PMMA were coated with salivary pellicle. Surface hydrophilicity, bactericidality, and Coulomb repulsion between the negatively charged bacteria and the grafted surface contributed to the effectiveness.

Highlights

Persistent biofilm formation on medical devices such as implants, catheters, and ureteral stents can cause chronic infection and, often leads to replacement
This study comparatively investigated the antibacterial effect of polymethyl methacrylate (PMMA) grafted with poly(2-hydroxyethyl methacrylate) (pHEMA) or polyethylene glycol methacrylate (PEGMA) against adhesion of two bacteria, Streptococcus mutans and Escherichia coli
Because the PMMA discs were smoother than the PMMA-pHEMA and PMMA-PEGMA discs, all PMMA discs were roughened to similar roughness as the other 2 materials to exclude the effect of roughness on bacterial adhesion

Summary

Introduction

Persistent biofilm formation on medical devices such as implants, catheters, and ureteral stents can cause chronic infection and, often leads to replacement. The development of a new strategy or materials to combat biofilm formation has been a critical topic of research. Numerous materials with antibacterial properties have been proposed. Silver is a broad-spectrum antimicrobial metal against Gram-positive and Gram-negative bacteria [1]. Its incorporation as silver zeolite or silver nanoparticles has been described for use in medical devices [2]. Other inorganic chemicals demonstrating antibiotic activity in the form of nanoparticles include ZnO [3], TiO2 [4], Cu and CuO [5]

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