Document Type
Article
Publication Date
2011
Abstract
Human dental enamel forms over a period of 2 – 4 years by substituting the enamel matrix, a protein gel mostly composed of a single protein, amelogenin with fibrous apatite nanocrystals. Self-assembly of a dense amelogenin matrix is presumed to direct the growth of apatite fibers and their organization into bundles that eventually comprise the mature enamel, the hardest tissue in the mammalian body. This work aims to establish the physicochemical and biochemical conditions for the synthesis of fibrous apatite crystals under the control of a recombinant fulllength human amelogenin matrix in combination with a programmable titration system. The growth of apatite substrates was initiated from supersaturated calcium phosphate solutions in the presence of dispersed amelogenin assemblies. It was shown earlier and confirmed in this study that binding of amelogenin onto apatite surfaces presents the first step that leads to substratespecific crystal growth. In this work, we report enhanced nucleation and growth under conditions at which amelogenin and apatite carry opposite charges and adsorption of the protein onto the apatite seeds is even more favored. Experiments at pH below the isoelectric point of amelogenin showed increased protein binding to apatite and at low Ca/P molar ratios resulted in a change in crystal morphology from plate-like to fibrous and rod-shaped. Concentrations of calcium and phosphate ions in the supernatant did not show drastic decreases throughout the titration period, indicating controlled precipitation from the protein suspension metastable with respect to calcium phosphate. It is argued that ameloblasts in the developing enamel may vary the density of the protein matrix at the nano scale by varying local pH, and thus control the interaction between the mineral and protein phases. The biomimetic experimental setting applied in this study has thus proven as convenient for gaining insight into the fundamental nature of the process of amelogenesis.
Recommended Citation
Uskoković V, Li W, Habelitz S. Biomimetic precipitation of uniaxially grown calcium phosphate crystals from full-length human amelogenin sols. Journal of Bionic Engineering. 2011;8(2):114-121. doi:10.1016/S1672-6529(11)60017-6.
Copyright
Elsevier
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Included in
Biochemistry Commons, Genetic Phenomena Commons, Genetic Processes Commons, Genetic Structures Commons, Medical Genetics Commons
Comments
NOTICE: this is the author’s version of a work that was accepted for publication in Journal of Bionic Engineering. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Bionic Engineering, volume 8, issue 2, in 2011. DOI: 10.1016/S1672-6529(11)60017-6
The Creative Commons license below applies only to this version of the article.