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Poly-l-Lysine Templated Silicas: Using Polypeptide Secondary Structure to Control Oxide Pore Architectures

Hawkins, Kristy M. and Wang, Steven S.-S. and Ford, David M. and Shantz, Daniel F. (2004) Poly-l-Lysine Templated Silicas: Using Polypeptide Secondary Structure to Control Oxide Pore Architectures. Journal of the American Chemical Society, 126 (29). pp. 9112-9119. ISSN 0002-7863. doi:10.1021/ja049936o. https://resolver.caltech.edu/CaltechAUTHORS:20170421-074322738

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Abstract

Utilizing polypeptide secondary structure as a means for controlling oxide pore architectures is explored. Poly-l-lysine is used as a model polypeptide as its folding behavior is well understood and compatible with the sol−gel chemistry of silica. Here, we show that silicas synthesized with poly-l-lysine in a α-helix conformation possess cylindrical pores that are approximately 1.5 nm in size, whereas silicas synthesized with poly-l-lysine in a β-sheet conformation possess larger pores, the size of which are a function of the poly-l-lysine concentration, or in other words the size of the aggregate. In both cases, highly porous materials are obtained. In-situ circular dichroism measurements of the synthesis mixtures show that the poly-l-lysine secondary structure is not perturbed during synthesis. Infrared spectroscopy of the as-synthesized materials is consistent with the poly-l-lysine retaining its secondary structure. Grand canonical Monte Carlo simulations were also performed to validate the interpretation of the experimental adsorption results. The experimental isotherms are consistent with simulated isotherms of cylindrical pores 1.3−1.7 nm in size, in good agreement with expected values. Our results suggest a new avenue for synthesizing porous oxides with highly tuneable pore sizes and shapes under mild conditions.


Item Type:Article
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http://dx.doi.org/10.1021/ja049936oDOIArticle
http://pubs.acs.org/doi/abs/10.1021/ja049936oPublisherArticle
http://pubs.acs.org/doi/suppl/10.1021/ja049936oPublisherSupporting Information
Additional Information:© 2004 American Chemical Society. Received 5 January 2004. Published online 2 July 2004. Published in print 1 July 2004. K.M.H. acknowledges the Engineering Academic Programs Office at Texas A&M for a summer research fellowship. K. M. H. and D. F. S. also acknowledge the Texas Advanced Research Program for financial support. The SAXS instrument was purchased from funds obtained under NSF grant CTS-0215838. The authors acknowledge the Microscopy and Imaging Center (MIC) at Texas A&M for access to the FE-SEM and TEM instrumentation. The authors also thank T. Good and J. M. Scholtz for useful discussions, J. Schmittschmitt for discussions about the CD experiments, H. Cheng for acquiring SAXS data on the PLL solutions, and Texas A&M University for financial support.
Funders:
Funding AgencyGrant Number
Texas A&M UniversityUNSPECIFIED
Texas Advanced Research ProgramUNSPECIFIED
NSFCTS-0215838
Issue or Number:29
DOI:10.1021/ja049936o
Record Number:CaltechAUTHORS:20170421-074322738
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20170421-074322738
Official Citation:Poly-l-Lysine Templated Silicas:  Using Polypeptide Secondary Structure to Control Oxide Pore Architectures Kristy M. Hawkins, Steven S.-S. Wang, David M. Ford, and Daniel F. Shantz Journal of the American Chemical Society 2004 126 (29), 9112-9119 DOI: 10.1021/ja049936o
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:76793
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:21 Apr 2017 18:33
Last Modified:15 Nov 2021 17:02

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