Nanoindentation Response of 3D Printed PEGDA Hydrogels in a Hydrated Environment

Mohammad Hakim Khalili, Craig J. Williams, Christian Micallef, Fabian Duarte-Martinez, Ashfaq Afsar, Rujing Zhang, Sandra Wilson, Eleftheria Dossi, Susan A. Impey, Saurav Goel, Adrianus Indrat Aria

Research output: Journal PublicationArticlepeer-review

8 Citations (Scopus)

Abstract

Hydrogels are commonly used materials in tissue engineering and organ-on-chip devices. This study investigated the nanomechanical properties of monolithic and multilayered poly(ethylene glycol) diacrylate (PEGDA) hydrogels manufactured using bulk polymerization and layer-by-layer projection lithography processes, respectively. An increase in the number of layers (or reduction in layer thickness) from 1 to 8 and further to 60 results in a reduction in the elastic modulus from 5.53 to 1.69 and further to 0.67 MPa, respectively. It was found that a decrease in the number of layers induces a lower creep index (CIT) in three-dimensional (3D) printed PEGDA hydrogels. This reduction is attributed to mesoscale imperfections that appear as pockets of voids at the interfaces of the multilayered hydrogels attributed to localized regions of unreacted prepolymers, resulting in variations in defect density in the samples examined. An increase in the degree of cross-linking introduced by a higher dosage of ultraviolet (UV) exposure leads to a higher elastic modulus. This implies that the elastic modulus and creep behavior of hydrogels are governed and influenced by the degree of cross-linking and defect density of the layers and interfaces. These findings can guide an optimal manufacturing pathway to obtain the desirable nanomechanical properties in 3D printed PEGDA hydrogels, critical for the performance of living cells and tissues, which can be engineered through control of the fabrication parameters.

Original languageEnglish
Pages (from-to)1180-1190
Number of pages11
JournalACS Applied Polymer Materials
Volume5
Issue number2
DOIs
Publication statusPublished - 10 Feb 2023
Externally publishedYes

Keywords

  • 3D printing
  • creep behavior
  • cross-linked hydrogels
  • nanoindentation
  • poly(ethylene glycol) diacrylate

ASJC Scopus subject areas

  • Process Chemistry and Technology
  • Polymers and Plastics
  • Organic Chemistry

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