Bulk Assessments of Relative Hydrophilicity/Hydrophobicity of PEGDA-Based Hydrogels

Bulk Assessments of Relative Hydrophilicity/hydrophobicity of PEGDA-based Hydrogels

 

Jessica Long¹, Dany Munoz-Pinto¹, Mariah Hahn^1
1 Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843

 

Abstract: Appropriate characterization of the hydrophilicity/hydrophobicity of hydrogels is important since the hydrophilic/hydrophobic characteristics of engineered scaffolds play a relevant role for tissue engineering applications. Its modulation affects protein adsorption, cell adhesion, migration, and differentiation. We propose the use of swelling ratios of materials in solvents with different polarity as a relative assessment of bulk hydrophilic/hydrophobic characteristics.  As a model to validate this method, we used polyethylene glycol diacrylate (PEGDA) hydrogels with the incorporation of increasing levels of two different monomers:  hydrophilic hydroxyethyl methacrylate (HEMA) and hydrophobic trimethoxysilylpropyl methacrylate (TMSPM).  An initial screening of swelling assessments was performed using DDI H₂O and aqueous 70% isopropanol. Formulations with significant difference were selected and their trends were compared to traditional contact angle evaluations. In addition, fibrinogen (FG) adsorption was measured.  As expected, the introduction of the hydrophobic TMSPM caused the hydrogel to exhibit an increase in hydrophobic properties.  Interestingly, the addition of the hydrophilic monomer HEMA seems to enhance both the hydrophobicity and the FG adsorption of the hydrogel.