title: Numerical investigation of the influence of pattern topology on the mechanical behavior of PEGDA hydrogels.
abstract: Poly(ethylene glycol) diacrylate (PEGDA) hydrogels can be potentially used as scaffold material for tissue engineered heart valves (TEHVs) due to their good biocompatibility and biomechanical tunability. The photolithographic patterning technique is an effective approach to pattern PEGDA hydrogels to mimic the mechanical behavior of native biological tissues that are intrinsically anisotropic. The material properties of patterned PEGDA hydrogels largely depend on the pattern topology. In this paper, we adopt a newly proposed computational framework for fibrous biomaterials to numerically investigate the influence of pattern topology, including pattern ratio, orientation and waviness, on the mechanical behavior of patterned PEGDA hydrogels. The material parameters for the base hydrogel and the pattern stripes are directly calibrated from published experimental data. Several experimental observations reported in the literature are captured in the simulation, including the nonlinear relationship between pattern ratio and material linear modulus, and the decrease of material anisotropy when pattern ratio increases. We further numerically demonstrate that a three-region (toe-heel-linear) stress-strain relationship typically exhibited by biological tissues can be obtained by tuning the pattern waviness and the relative stiffness between the base hydrogel and pattern stripes. The numerical strategy and simulation results presented here can provide helpful guidance to optimize pattern design of PEGDA hydrogels toward the targeted material mechanical properties, therefore advance the development of TEHVs.
  
  
  
  Poly(ethylene glycol) diacrylate (PEGDA) hydrogels can be used as scaffold material for tissue engineered heart values (TEHVs) providing a promising alternative to generate suitable heart valve replacement method. The patterning of PEGDA hydrogels using photolithographic techniques creates materials that mimic the mechanical behavior of native heart valve tissues. However, targeted material properties are obtained via a trial-and-error process. Depending on experiments alone to explore the influence of pattern topology is expensive and time-consuming. We combine a newly proposed computational framework with published experimental data to numerically investigate the influence of pattern geometry on the mechanical behavior of patterned PEGDA hydrogels. The numerical strategy and simulation results presented here can provide guidance to optimize the design of PEGDA hydrogels with targeted material properties, therefore advance the development of TEHVs.
authors.affiliation: Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, USA.
authors.forename: Tao
authors.initials: T
authors.lastname: Jin
authors.affiliation: Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, USA. Electronic address: ilinca.s@rice.edu.
authors.forename: Ilinca
authors.initials: I
authors.lastname: Stanciulescu
mesh_terms: D016880:Anisotropy; D002138:Calibration; D003198:Computer Simulation; D003432:Cross-Linking Reagents / Q000737:chemistry; D020342:Finite Element Analysis; D020100:Hydrogels / Q000737:chemistry*; D055595:Mechanical Phenomena; D009716:Numerical Analysis, Computer-Assisted; D011092:Polyethylene Glycols / Q000737:chemistry*; D015203:Reproducibility of Results; D013314:Stress, Mechanical
chemical_list: D003432:Cross-Linking Reagents; D020100:Hydrogels; C437167:poly(ethylene glycol)diacrylate; D011092:Polyethylene Glycols
keywords: Embedded fiber approach; PEGDA hydrogel; Pattern topology