Stefan Habelitz

Research Interests

Understanding mineral and protein interaction. We are using recombinant dental proteins to synthesize enaeml in-vitro.

Research Summary

My research focuses on the biomineralization process of calcified tissues in regards to 1.) the relationship between micro/nano-structure and properties, 2.) mechanisms of interactions between organic and inorganic molecules or phases, 3.) application of biomimetic approaches for the regeneration of dental hard tissues using recombinant proteins and/or dental stem cells. Understanding the fundamental mechanisms involved in biomineralization could provide the basic principles needed to facilitate fabrication of bone, dentin or enamel-like materials for tissue regeneration or new tissue synthesis in-vivo and in-vitro.  Currently, we are applying a series of non-collagenous proteins that are involved in the mineralization process and study their effectiveness for functional remineralization of dental collagen fibrils, using atomic force microscopy, micro-Raman spectroscopy and nanoindentation.  In collaboration with Faculty in the Department of Orofacial Sciences at UCSF, we are using recombinant enamel proteins and enzymes for the in-vitro synthesis of human dental enamel. We are investigating the importance of the physical-chemical conditions on the ability of several enamel matrix proteins to interact with nucleating calcium phosphate mineral and to control the growth and morphology of apatite crystals. My research group has setup an experimental design that facilitates continuous crystal growth under metastable saturation level by means of a pH-stat titration system. Using a number of amelogenin splice products and recombinant enamel proteases in mineralizing solutions we are mimicking amelogenesis in-vitro without the use of ameloblast cells. This approach has so far succeeded in the formation of micrometer thin layers of an enamel-like material on a glass-ceramic substrate.

Selected Publications

S. Habelitz, S. J. Marshall, G. W. Marshall, M. Balooch. Mechanical properties of human enamel on the nanometre scale, Arch. Oral Biol. 46, 173-183, (2001).

S. Habelitz, S. J. Marshall, A. Kullar, P. K. DenBesten, M. Balooch, G.W. Marshall, W. Li.  Amelogenin-guided crystal growth on fluoroapatite glass-ceramics, J. Dent. Res. 83, 698-702 (2004).

S. Habelitz, B. J. Rodriguez,  S. J. Marshall, G. W. Marshal, S. Kalinin, A. Gruverman. Peritubular Dentin Lacks Piezoelectricity, J. Dent. Res. 2007, 86(9): 908-911.

M. Balooch, S. Habelitz, J. Kinney, S. J. Marshall, G. W. Marshall. Mechanical properties of mineralized collagen fibrils as influenced by demineralization. J Struct Biol (2008) 162; 404-10.

X. He, W. Li, S. Habelitz. The cooperative self-assembly of 25 kDa and 23 kDa amelogenins.  submitted to J. Struct. Biol. (in print for December issue 2008), available online: doi:10.1016/j.jsb.2008.09.005