A novel methacrylate derivative polymer that resists bacterial cell-mediated biodegradation

Dhiraj Kumar, Debarati Ghose, Robert D. Bolskar, Isha Mutreja, Robert S. Jones

Research output: Contribution to journalArticlepeer-review

Abstract

This study tests biodegradation resistance of a custom synthesized novel ethylene glycol ethyl methacrylate (EGEMA) with ester bond linkages that are external to the central polymer backbone when polymerized. Ethylene glycol dimethacrylate (EGDMA) with internal ester bond linkages and EGEMA discs were prepared in a polytetrafluoroethylene (PTFE) mold using 40 μl macromer and photo/co-initiator mixture cured for 40 s at 1000 mW/cm2. The discs were stored in the constant presence of Streptococcus mutans (S. mutans) in Todd Hewitt Yeast + Glucose (THYE+G) media up to 9 weeks (n = 8 for each macromer type) and physical/mechanical properties were assessed. Initial measurements EGEMA versus EGDMA polymer discs showed equivalent degree of conversion (45.69% ± 2.38 vs. 46.79% ± 4.64), diametral tensile stress (DTS; 8.12± 2.92 MPa vs. 6.02 ± 1.48 MPa), and low subsurface optical defects (0.41% ± 0.254% vs. 0.11% ± 0.074%). The initial surface wettability (contact angle) was slightly higher (p ≤.012) for EGEMA (62.02° ± 3.56) than EGDMA (53.86° ± 5.61°). EGDMA showed higher initial Vicker's hardness than EGEMA (8.03 ± 0.88 HV vs. 5.93 ± 0.69 HV; p ≤.001). After 9 weeks of S. mutans exposure, EGEMA (ΔDTS—1.30 MPa) showed higher resistance to biodegradation effects with a superior DTS than EGDMA (ΔDTS—6.39 MPa) (p =.0039). Visible and scanning electron microscopy images of EGEMA show less surface cracking and defects than EGDMA. EGDMA had higher loss of material (18.9% vs. 8.5%, p =.0009), relative changes to fracture toughness (92.5% vs. 49.2%, p =.0022) and increased water sorption (6.1% vs. 1.9%, p =.0022) compared to EGEMA discs. The flipped external ester group linkage design is attributed to EGEMA showing higher resistance to bacterial degradation effects than an internal ester group linkage design methacrylate.

Bibliographical note

Funding Information:
This works is supported by NIH/NIDCR 5R44DE024013. This work is a collaboration between TDA Research (PI Bob Bolskar) and Minnesota Dental Research Center for Biomaterials and Biomechanics, School of Dentistry, University of Minnesota. Parts of this work were carried out in the Characterization Facility, University of Minnesota, a member of the NSF ‐ Funded Materials Research Facilities Network ( www.mrfn.org ) via the MRSEC program. The Hitachi SU8320 CryoSEM and Cryo‐specimen preparation system were provided by NSF MRI DMR‐1229263 program. Authors would like to thank Conrado Aparicio, Alex Fok, Young Hoe and Dr. Hooi Pin Chew for allowing access and assistance with characterization equipment.

Publisher Copyright:
© 2021 Wiley Periodicals LLC.

Keywords

  • Streptococcus mutans
  • Streptococcus mutans biofilm
  • Streptococcus mutans: glycol methacrylate
  • ethylene glycol dimethacrylate
  • Ethylene glycol ethyl methacrylate
  • Biomaterials
  • Dental biomaterials
  • Biodegradable
  • biodegradation

PubMed: MeSH publication types

  • Journal Article

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