Atomic force microscopy reveals hydroxyapatite-citrate interfacial structure at the atomic level.
An approach to organic-inorganic interfacial structure at the atomic level is a great challenge in the studies of biomineralization. We demonstrate that atomic force microscopy (AFM) is powerful tool to discover the biomineral interface in detail. By using a model system of (100) hydroxyapatite (HAP) face and citrate, it reveals experimentally that only a side carboxylate and a surface calcium ion are involved in the binding effect during the citrate adsorption, which is against the previous understandings by using Langmuir adsorption and computer simulation. Furthermore, the adsorbed citrate molecules can use their free carboxylate and hydroxyl groups to be self-assembled on the HAP surface. AFM examination also finds that the presence of citrate molecules on the HAP crystal faces can enhance the adhesion force of the HAP surface. We suggest that the established AFM method can be used for a precise and direct understanding of biointerfaces at the atomic level.
Jiang
Wenge
W
Center for Biomaterials and Biopathways and Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China.
Pan
Haihua
H
Cai
Yurong
Y
Tao
Jinhui
J
Liu
Peng
P
Xu
Xurong
X
Tang
Ruikang
R
D019343:Citric Acid / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D018625:Microscopy, Atomic Force / Q000379:methods*; D015394:Molecular Structure; D017550:Spectroscopy, Fourier Transform Infrared
D019343:Citric Acid; D017886:Durapatite