Whey protein isolate : a versatile dairy-derived hydrogel for bone and vascular tissue engineering and antimicrobial applications

Douglas, T.E.L. (2024) Whey protein isolate : a versatile dairy-derived hydrogel for bone and vascular tissue engineering and antimicrobial applications. Hemijska Industrija, 78 (1S): 11. ISSN 0367-598X

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Abstract

INTRODUCTION: Whey Protein Isolate (WPI) is an inexpensive by-product of the dairy industry, available in large quantities and used as a dietary supplement. WPI is over 97% protein; three-quarters is beta-lactoglobulin (β-LG) [1]. WPI in cell culture medium promoted the proliferation and differentiation of bone-forming cells [2]. Solutions of WPI can be heated to form hydrogels, which withstand sterilization by autoclaving; an important practical advantage. Denaturation of β-LG leads to increased hydrophobic interactions and disulphide bond formation and thus crosslinking to form the polymer hydrogel network [3]. We have studied WPI hydrogels as scaffolds for bone-forming cells and carriers of hydrophobic substances. EXPERIMENTAL: WPI hydrogels 15% to 40% (w/v) have been made [4-5]; inorganic particles, like bioactive glasses, alpha-tricalcium phosphate, aragonite and hydroxyapatite (HA) can easily be added during hydrogel formation [6-9]. Hydrophobic molecules such as phloroglucinol (PG), the fundamental subunit of marine polyphenols, and poly-gamma-glutamic acid (PGGA), can be incorporated during hydrogel formation. RESULTS AND DISCUSSION: WPI hydrogels support the adhesion and growth of a range of bone-forming cells, including MG-63 osteoblast-like cells, normal human foetal osteoblasts (hFOB) normal mouse calvarial preosteoblasts (MC3T3-E1) and dental pulp stem cells [6-10], as well as human umbilical vascular endothelial cells (HUVEC) [5]. Addition of aragonite [8] and PGGA [11] promoted osteoblastic differentiation, while incorporation of PG endowed antimicrobial activity towards a wide range of microbes including methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis while maintaining cytocompatibility [11]. CONCLUSIONS: WPI hydrogels are both promising scaffolds for bone cells and hydrophobic drug carriers.