title: Conformational and adsorptive characteristics of albumin affect interfacial protein boundary lubrication: from experimental to molecular dynamics simulation approaches.
abstract: The lifetime of artificial joints is mainly determined by their biotribological properties. Synovial fluid which consists of various biological molecules acts as the lubricant. Among the compositions of synovial fluid, albumin is the most abundant protein. Under high load and low sliding speed articulation of artificial joint, it is believed the lubricants form protective layers on the sliding surfaces under the boundary lubrication mechanism. The protective molecular layer keeps two surfaces from direct collision and thus decreases the possibility of wear damage. However, the lubricating ability of the molecular layer may vary due to the conformational change of albumin in the process. In this study, we investigated the influence of albumin conformation on the adsorption behaviors on the articulating surfaces and discuss the relationship between adsorbed albumin and its tribological behaviors. We performed the friction tests to study the effects of albumin unfolding on the frictional behaviors. The novelty of this research is to further carry out molecular dynamics simulation, and protein adsorption experiments to investigate the mechanisms of the albumin-mediated boundary lubrication of arthroplastic materials. It was observed that the thermal processes induce the loss of secondary structure of albumin. The compactness of the unfolded structure leads to a higher adsorption rate onto the articulating material surface and results in the increase of friction coefficient.
authors.affiliation: Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei, Taiwan. hwfang@ntut.edu.tw
authors.forename: Hsu-Wei
authors.initials: HW
authors.lastname: Fang
authors.forename: Man-Ching
authors.initials: MC
authors.lastname: Hsieh
authors.forename: Huei-Ting
authors.initials: HT
authors.lastname: Huang
authors.forename: Cheng-Yen
authors.initials: CY
authors.lastname: Tsai
authors.forename: Min-Hui
authors.initials: MH
authors.lastname: Chang
mesh_terms: D000327:Adsorption; D000418:Albumins / Q000737:chemistry*; D001178:Arthroplasty; D002942:Circular Dichroism; D003198:Computer Simulation; D017276:Friction; D006801:Humans; D008153:Lubrication; D008958:Models, Molecular; D020959:Polyethylene / Q000737:chemistry; D011487:Protein Conformation; D012996:Solutions; D013499:Surface Properties; D013696:Temperature
chemical_list: D000418:Albumins; D012996:Solutions; D020959:Polyethylene