title: Kinetics and thermodynamics studies on the BMP-2 adsorption onto hydroxyapatite surface with different multi-morphological features.
abstract: The effect of the surface topography on protein adsorption process is of great significance for designing hydroxyapatite (HA) ceramic material surfaces. In this work, three different topographies of HA materials HA-sheet, HA-rod, and HA-whisker were synthesized and testified by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Brunauer-Emmett-Teller (BET) and a field emission scanning electron microscopy (FE-SEM). We have systematically investigated the adsorption kinetics and thermodynamics of bone morphogenetic proteins (BMP-2) on the three different topography surfaces of HA, respectively. The results showed that the maximum adsorption capacities of HA-sheet, HA-rod and HA-whisker were (219.96 ± 10.18), (247.13 ± 12.35), and (354.67 ± 17.73) μg · g(-1), respectively. Kinetic parameters, rate constants, equilibrium adsorption capacities and related correlation coefficients, for each kinetic model were calculated as well as discussed. It demonstrated that the adsorption of BMP-2 onto HA could be described by the pseudo second-order equation. Adsorption of BMP-2 onto HA followed the Langmuir isotherm. It confirmed that compared with other samples HA-whisker had more adsorption sites for its high specific surface area which could provide more opportunities for protein molecules. The adsorption processes were endothermic (ΔH > 0), spontaneous (ΔG < 0) and entropy increasing (ΔS > 0). A possible adsorption mechanism has been proposed. In addition, the BMP-2 could be adsorbed to the surface which existed slight conformational changes by FT-IR.
authors.affiliation: College of Science, Sichuan Agricultural University, Ya'an 625014, PR China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Lu
authors.affiliation: College of Science, Sichuan Agricultural University, Ya'an 625014, PR China.
authors.forename: Changxin
authors.initials: C
authors.lastname: Huangfu
authors.affiliation: College of Science, Sichuan Agricultural University, Ya'an 625014, PR China.
authors.forename: Yanying
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Science, Sichuan Agricultural University, Ya'an 625014, PR China.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Ge
authors.affiliation: College of Science, Sichuan Agricultural University, Ya'an 625014, PR China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Yao
authors.affiliation: College of Science, Sichuan Agricultural University, Ya'an 625014, PR China.
authors.forename: Ping
authors.initials: P
authors.lastname: Zou
authors.affiliation: College of Science, Sichuan Agricultural University, Ya'an 625014, PR China.
authors.forename: Guangtu
authors.initials: G
authors.lastname: Wang
authors.affiliation: Institute of Animal Genetics and Breeding, Sichuan Agricultural University, Wenjiang, Sichuan 611130, PR China.
authors.forename: Hua
authors.initials: H
authors.lastname: He
authors.affiliation: College of Science, Sichuan Agricultural University, Ya'an 625014, PR China. Electronic address: rhbscu@gmail.com.
authors.forename: Hanbing
authors.initials: H
authors.lastname: Rao
mesh_terms: D000327:Adsorption; D055396:Bone Morphogenetic Protein 2 / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D007700:Kinetics; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: D055396:Bone Morphogenetic Protein 2; D014874:Water Pollutants, Chemical; D017886:Durapatite
keywords: Adsorption isotherm; BMP-2; Hydroxyapatite (HA); Kinetics and thermodynamic; Topographies