TY - JOUR
T1 - Utilizing a degradation prediction pathway system to understand how a novel methacrylate derivative polymer with flipped external ester groups retains physico-mechanical properties following esterase exposure
AU - Kumar, Dhiraj
AU - Ghose, Debarati
AU - Mutreja, Isha
AU - Bolskar, Robert D.
AU - Aparicio, Conrado
AU - Jones, Robert S.
N1 - Funding Information:
This works is supported by NIH/NIDCR 5R44DE024013-03. This work is a collaboration between TDA Research (PI Bob Bolskar) and University of Minnesota (RS Jones and Conrado Aparicio). 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 SEM specimen preparation system were provided by NSF MRI DMR-1229263 program. Authors would like to thank Young Heo and Dr. Hooi Pin Chew for allowing access and setting up the MTS system and OCT IVS 2000 system respectively. We also acknowledge the open source resources of the EAWAG (http://eawag-bbd.ethz.ch/predict/) within the Federal Institutes of Technology ETH Zurich that utilizes the University of Minnesota biocatalysis/biodegradation database for biodegradation pathway prediction. All co-authors may potentially be named on a TDA Research/University of Minnesota patent application.
Funding Information:
This works is supported by NIH/NIDCR 5R44DE024013-03 . This work is a collaboration between TDA Research (PI Bob Bolskar) and University of Minnesota (RS Jones and Conrado Aparicio). 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 SEM specimen preparation system were provided by NSF MRI DMR-1229263 program. Authors would like to thank Young Heo and Dr. Hooi Pin Chew for allowing access and setting up the MTS system and OCT IVS 2000 system respectively. We also acknowledge the open source resources of the EAWAG ( http://eawag-bbd.ethz.ch/predict/ ) within the Federal Institutes of Technology ETH Zurich that utilizes the University of Minnesota biocatalysis/biodegradation database for biodegradation pathway prediction.
Publisher Copyright:
© 2021 The Academy of Dental Materials
PY - 2022/2
Y1 - 2022/2
N2 - Objective: The region of failure for current methacrylates (i.e. derivatives of acrylates) are ester bond linkages that hydrolyze in the presence of salivary and bacterial esterases that break the polymer network backbone. This effect decreases the mechanical properties of methacrylate-based materials. Methods: The ethylene glycol dimethacrylate (EGDMA) or novel ethylene glycol ethyl methacrylate (EGEMA) discs were prepared using 40 µL of the curing mixture containing photo/co-initiators for 40 s in a PTFE mold at 1000 mW/cm2. The degree of conversion was used as a quality control measure for the prepared discs, followed by physical, mechanical, and chemical characterization of discs properties before and after cholesterol esterase treatment. Results: After 9 weeks of standardized cholesterol esterase (CEase) exposure, EGDMA discs showed exponential loss of material (p = 0.0296), strength (p = 0.0014) and increased water sorption (p = 0.0002) compared to EGEMA discs. We integrated a degradation prediction pathway system to LC/MS and GC/MS analyses to elucidate the degradation by-products of both EGEMA and EGDMA polymers. GC/MS analysis demonstrated that the esterase catalysis was directed to central polymer backbone breakage, producing ethylene glycol, for EGDMA, and to side chain breakage, producing ethanol, for EGEMA. The flipped external ester group linkage design is attributed to EGEMA showing higher resistance to esterase biodegradation and changes in mechanical and physical properties than EGDMA. Significance: EGEMA is a potential substitute for common macromer diluents, such as EGDMA, based on its resistance to biodegradation effects. This work inspires the flipped external group design to be applied to analogs of current larger, hydrophobic strength bearing macromers used in future dental material formulations.
AB - Objective: The region of failure for current methacrylates (i.e. derivatives of acrylates) are ester bond linkages that hydrolyze in the presence of salivary and bacterial esterases that break the polymer network backbone. This effect decreases the mechanical properties of methacrylate-based materials. Methods: The ethylene glycol dimethacrylate (EGDMA) or novel ethylene glycol ethyl methacrylate (EGEMA) discs were prepared using 40 µL of the curing mixture containing photo/co-initiators for 40 s in a PTFE mold at 1000 mW/cm2. The degree of conversion was used as a quality control measure for the prepared discs, followed by physical, mechanical, and chemical characterization of discs properties before and after cholesterol esterase treatment. Results: After 9 weeks of standardized cholesterol esterase (CEase) exposure, EGDMA discs showed exponential loss of material (p = 0.0296), strength (p = 0.0014) and increased water sorption (p = 0.0002) compared to EGEMA discs. We integrated a degradation prediction pathway system to LC/MS and GC/MS analyses to elucidate the degradation by-products of both EGEMA and EGDMA polymers. GC/MS analysis demonstrated that the esterase catalysis was directed to central polymer backbone breakage, producing ethylene glycol, for EGDMA, and to side chain breakage, producing ethanol, for EGEMA. The flipped external ester group linkage design is attributed to EGEMA showing higher resistance to esterase biodegradation and changes in mechanical and physical properties than EGDMA. Significance: EGEMA is a potential substitute for common macromer diluents, such as EGDMA, based on its resistance to biodegradation effects. This work inspires the flipped external group design to be applied to analogs of current larger, hydrophobic strength bearing macromers used in future dental material formulations.
KW - Degradable linkage
KW - Dental composite
KW - Enzymatic degradation
KW - Ethylene glycol dimethacrylate
KW - Polymer backbone preservation
UR - http://www.scopus.com/inward/record.url?scp=85121360105&partnerID=8YFLogxK
U2 - 10.1016/j.dental.2021.12.008
DO - 10.1016/j.dental.2021.12.008
M3 - Article
C2 - 34933759
AN - SCOPUS:85121360105
SN - 0109-5641
VL - 38
SP - 251
EP - 265
JO - Dental Materials
JF - Dental Materials
IS - 2
ER -