WPI hydrogels as a potential substrate for tissue scaffolds: mechanical properties

• Published in: Mechanics of soft materials (Online) 2022-12, Vol.4 (1), Article 6
• Main Authors: Dvora, Mia, Warwick, Paityn, Henry, James E.
• Format: Article
• Language: English
• Subjects: Biomaterials; Complex Fluids and Microfluidics; Engineering; Original Paper; Soft and Granular Matter; Theoretical and Applied Mechanics
• ISSN: 2524-5600; 2524-5619
• DOI: 10.1007/s42558-022-00044-3

Whey protein isolate (WPI) sol–gel is proposed for use as a bone tissue regeneration scaffold based on its biocompatibility and potentially suitable mechanical properties. The gel surface successfully supports the attachment and proliferation of healthy, motile MC3T3-E1 preosteoblast cells, as confirmed by scanning electron microscopy. Material stiffness and ultimate compressive and tensile properties of high-protein concentration, heat-induced gels from WPI were characterized, and trends were established based on the protein and CaCl 2 concentrations of the gel. The elastic modulus and ultimate material strength were determined to be functions of both varying concentrations. Scanning electron micrographs of gel cross-sections confirmed the network hypothesized based on the macroscopic mechanical testing. One finding challenges the linear nature of concentration dependence reported for similar, low-concentration whey protein gels. A maximum gel strength and subsequent decrease were found at 35% w/v WPI due to local charge screening. The strongest of the gels constructed failed at 2.37 ± 0.09 MPa and had an elastic modulus of 1.65 ± 0.02 MPa, or within one order of magnitude of values considered acceptable for a bone-regeneration scaffold.