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In JoVE (1)
Other Publications (2)
Articles by Shivendra Pandey in JoVE
Origami Inspired Self-assembly of Patterned and Reconfigurable Particles
Shivendra Pandey1, Evin Gultepe1, David H. Gracias1,2
1Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, 2Department of Chemistry, The Johns Hopkins University
Other articles by Shivendra Pandey on PubMed
Green Fluorescent Protein for in Situ Synthesis of Highly Uniform Au Nanoparticles and Monitoring Protein Denaturation
Journal of Colloid and Interface Science. Oct, 2008 | Pubmed ID: 18684469
Purified recombinant green fluorescent protein (GFP) expressed in E. coli was used for single-step synthesis of gold nanoparticles (Au NPs) with extraordinary size specificity in aqueous medium. The fluorescence of GFP offered a probe for concomitant changes in the protein during the course of synthesis, in addition to the monitoring of the time-dependent formation of Au NPs by the surface plasmon resonance. Reaction of AuCl(4)(-) with the protein produced spherical Au NPs having diameters ranging from 5-70 nm. Remarkably, addition of 1.0x10(-5) M AgNO(3) in the medium produced uniform spherical Au NPs with particle diameter of 2.2+/-0.5 nm. Fluorescence spectroscopic measurements suggest that during synthesis of Au NPs in absence of AgNO(3), partial denaturation of the protein occurred resulting in the lowering of fluorescence intensity. On the other hand, when the NPs were synthesized in the presence of AgNO(3) complete denaturation of the protein with complete loss of fluorescence could be observed, which was further confirmed by native and sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE). However, use of AgNO(3) only resulted neither in the formation of NPs nor had any significant effect on the fluorescence of GFP.
Proceedings of the National Academy of Sciences of the United States of America. Dec, 2011 | Pubmed ID: 22139373
Self-assembly has emerged as a paradigm for highly parallel fabrication of complex three-dimensional structures. However, there are few principles that guide a priori design, yield, and defect tolerance of self-assembling structures. We examine with experiment and theory the geometric principles that underlie self-folding of submillimeter-scale higher polyhedra from two-dimensional nets. In particular, we computationally search for nets within a large set of possibilities and then test these nets experimentally. Our main findings are that (i) compactness is a simple and effective design principle for maximizing the yield of self-folding polyhedra; and (ii) shortest paths from 2D nets to 3D polyhedra in the configuration space are important for rationalizing experimentally observed folding pathways. Our work provides a model problem amenable to experimental and theoretical analysis of design principles and pathways in self-assembly.