Charactering the Nanoparticle - Protein Interface

Nanoparticle-protein conjuagtes have been utilized in numerous applications such as sensing, self-assembly, and imaging. For these purposes, conjugation needs to be site-specific and should not perturb the structure and function of the protein. However, this is difficult to achieve as both nanoparticles and proteins are complex chemical systems, which can interact by numerous non-covalent interactions, or non-specific adsorption. Furthermore, characterization of the interface between the nanoparticle and protein is difficult and straightforward assays do not exist. Consequently the interface is poorly understood and remains to be one of the major barriers in employing nanoparticles in biological applications.

Our ultimate goal is to come up with general design rules for optimal conjugation of nanoparticles with a protein. Toward this end, we are studying the interface of nanoparticles with the proteins Ribonuclease S and Cytochrome c. We have determined how to label these proteins in a way that is site-specific. Current efforts are focused on studying the effect of labeling position, as well as nanoparticle ligand, size, and material on the biophysical properties of the protein. We are integrating our experimental results with molecular dynamics simulations, in collaboration with Prof. Wonmuk Hwang in the Biomedical Engineering Department at Texas A & M University.

M.-E. Aubin-Tam, W. Hwang, K. Hamad-Schifferli, "Site-directed nanoparticle labeling of cytochrome c," 2008, in submission.

M.-E. Aubin-Tam, K. Hamad-Schifferli, "Structure and Function of Nanoparticle-Protein Conjugates," Biomedical Materials, special issue: Advanced methods and protocols for the biomedical sciences, 2008, 3, 034001 invited contribution.
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M.-E. Aubin-Tam, H. Zhou, and K. Hamad-Schifferli, "Structure of cytochrome c at the interface with magnetic CoFe₂O₄ nanoparticles," Soft Matter, 2008, 4, 554-559.
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M.-E. Aubin-Tam and K. Hamad-Schifferli, "Gold nanoparticle-cytochrome c complexes: the effect of nanoparticle ligand charge on protein structure," Langmuir, 2005, 21 (26) 12080-12084.
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Langmuir's Most-Accessed Articles: October-December, 2005

M.-E. Aubin, D.G. Morales, K. Hamad-Schifferli, "Labeling Ribonuclease S with a 3nm Au nanoparticle by two-step assembly," Nano Letters, 2005, 5, 519-522.
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