Size-Controllable and pH-Sensitive Whey Protein Microgels as High-Performance Aqueous Biolubricants

• DOI: 10.1021/acsami.4c09771
• Publication Date: 2024-08-22T21:48:46Z
• Authors: Yifu Chu; Ziqian Zhao; Sabina Schreiber; Hongbo Zeng; Lingyun Chen
• Keywords: Lubricity; Biocompatibility; Aqueous two-phase system

Developing efficient aqueous biolubricants has become a significant focus of research due to their prevalence in biotribological contacts and enormous potential soft matter applications. In this study, size-controllable, pH-sensitive whey protein microgels were prepared using water-in-water emulsion template method from protein–polysaccharide phase separation. The granular hydrogel the exhibited superior lubricity, obtaining 2.7-fold 1.7-fold reductions coefficient friction (μ) compared native human saliva (μ = 0.30 0.81 0.52, respectively). also outstanding load-bearing capabilities, sustaining lubrication under normal forces up 5 N. Microgels with smaller size (1 μm) demonstrated better lubricating performance than 6 20 μm microgels. exceptional lubricity was synergistic effect ball-bearing mechanism hydration state Particularly at pH 7.4, layer surrounding highly negative charges contributed electrostatic repulsion among swollen microgels, leading an improved buffer ability separate contact surfaces effective rolling behavior. Such pH-dependent evidenced surface apparatus that adhesion between protein-coated protein-mica decreased 4.49 0.97 mN/m 7.89 0.36 mN/m, respectively, increasing isoelectronic point 7.4. Our findings fundamentally elucidated tribo-rheological properties mechanisms excellent biocompatibility environmental responsiveness, offering novel insights for food biomedical applications requiring biolubrication.