Title: 0345 - pH-Driven Self-sterilizing Materials With Antimicrobial and Antifouling Properties


Oscar Navarro (Presenter)
Oregon Health & Science University

Ana Fugolin, Oregon Health & Science University
Justin Merritt, Oregon Health & Science University
Jack Ferracane, Oregon Health & Science University
Carmem Pfeifer, Oregon Health & Science University


Objectives: To synthesize a series of carboxybetaine-based monomers with switching anti-fouling and anti-bacterial capabilities, and assess their kinetics of polymerization, mechanical properties and biofilm inhibition capacity.

Methods: Synthesized CB-Cn-Ring compounds (2-(methacryloyloxymethyl)-4-methyl-4-CnH2n+2-6-oxomorpholin-4-ium) (n=1-6) or positive control antifouling agent MPC (2-methacryloyloxyethylphosphorylcholine) were mixed at 0, 2.5 or 5.0wt% with experimental composites based on 90:10wt% UDMA:TEGDMA matrix. Fillers were introduced at 70wt% (95% 0.7 um barium glass and 5% colloidal silica). BAPO (phenylbis-(2,4,6-trimethylbenzoyl)-phosphine oxide, 2wt%) was used as photoinitiator. Degree of conversion (DC) and maximum rate of polymerization (RPmax) during photoactivation (800 mW/cm2) were followed in real-time with near-IR. Flexural Strength (FS) and Modulus (E) were obtained from 2x2x5 bars by 3-point bend testing after 24h dry and 7-day wet storage. Antimicrobial and antifouling properties were evaluated by bioluminescence (luciferase assay) and impingement test (area removed by precise water spray), respectively. Data were analyzed with one-way ANOVA/Tukey's test (α=0.05).

Results: The addition of CB-Cn-ring compounds led to similar or statistically higher DC than the control, while RPmax was significantly reduced for all formulations (Table). Mechanical properties (wet and dry) were not affected by the addition of the antibacterial compounds. In the ring conformation, the CB-Cn materials were expected to be antibacterial, but for the relatively short alkyl side chain length used here, similar titer counts of biofilm were observed in all groups. The antifouling effect would only be expected in the open ring form, which was confirmed by the results of the impingement test. Studies are underway with compounds bearing longer alkyl side chains, in an attempt to increase the antibacterial effects.

Conclusions: The experimental composite formulation containing CB-C6-Ring produce moderate antifouling effects. Importantly, the mechanical properties were not compromised, indicating it may be possible to incorporate longer alkyl side chains to increase the antibacterial effects in dental composites.


Download Image 1

This abstract is based on research that was funded entirely or partially by an outside source:
NIH-NIDCR R01-DE026113, K02-DE025280

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: None