New materials for proteomics

The post-genomic era promises great advances in human health, and the realization of this promise places huge demands on separation technology for proteins.  Improvements of more than an order of magnitude in protein separations are needed to understand how human cells function through their tens of thousands of proteins.  Characterizing proteins from living cells will enable the discovery of better cancer diagnostics and therapeutics, advance the discovery of more effective drugs, and hasten the cure of infectious diseases.  Materials that handle hydrophobic proteins will advance the nascent field of membrane proteomics.

Polyacrylamide forms pores for sieving of proteins when water is the solvent.  The essential idea here is that a material whose pores are defined by an inorganic matrix will allow the use of solvents compatible with hydrophobic membrane proteins.  We are studying ordered arrays of silica nanoparticles coated with 10 nm layers of covalently bound polyacrylamide.  To the right is a field-emission scanning electron micrograph showing the side view of an array of these silica nanoparticles, where each sphere has a diameter of 200 nm.  This material has the potential to replace the polyacrylamide gels that serve today as the workhorse of proteomics to allow study of memrbrane proteins.  The materials also offer geatly increased speed due to the thinness of the material.  The image demonstrates the crystalline order of the nanospheres.  The bottleneck between the particles is 30 nm, which is the optimal size for sieving proteins.  Our research is to investigate the electrophoretic transport of proteins through the contiguous nanopores in these materials, and investigate their use in fast proteomic analysis of membrane proteins.

These materials are also ideal for fast separations of peptides, whichis an important aspect of proteomics because proteins are typically digested into peptide for analysis, therefore, most proteomic analyses require a peptide separtion.  The figure below shows as fast peptide separation in these materials.  In part a, a chromatograpm using a conventional HPLC material is shown not to separte these, and in part b, we show that these three peptides are baseline-resolved in 10 s.  We are presently investigating the use of 2D separations for powerful resolution of complex peptide samples.

Students working on this project will learn about the leading-edge methods in separating proteins, the coupling of separations to mass spectrometry, the biological and health issues in proteomics, including post-translational modification.  Students will interact with scientists in companies developing technology in this field, and they will collaborate with researchers in a proteomics application.

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