151
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Slocik JM, Naik RR. Biomimetic synthesis of bimorphic nanostructures. Methods Mol Biol 2008; 474:53-60. [PMID: 19031060 DOI: 10.1007/978-1-59745-480-3_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The widespread interest in the use of biomimetic approaches for inorganic nanomaterial synthesis have led to the development of biomolecules (peptides, nucleic acids) as key components in material synthesis. Using biomolecules as building blocks, additional functionalities can be introduced by engineering multifunctional peptides that are capable of binding, nucleating, and assembling multiple materials at the nanoscale. We describe methodologies that exploit peptides for the synthesis of bimorphic nanostructures.
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152
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Ahmad G, Dickerson MB, Cai Y, Jones SE, Ernst EM, Vernon JP, Haluska MS, Fang Y, Wang J, Subramanyam G, Naik RR, Sandhage KH. Rapid Bioenabled Formation of Ferroelectric BaTiO3 at Room Temperature from an Aqueous Salt Solution at Near Neutral pH. J Am Chem Soc 2007; 130:4-5. [DOI: 10.1021/ja0744302] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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153
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Li X, Chen W, Zhan Q, Dai L, Sowards L, Pender M, Naik RR. Direct measurements of interactions between polypeptides and carbon nanotubes. J Phys Chem B 2007; 110:12621-5. [PMID: 16800593 DOI: 10.1021/jp061518d] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The interactions of various polypeptides with individual carbon nanotubes (CNTs), both multiwall (MW) and single wall (SW), were investigated by atomic force microscopy (AFM). While adhesion forces arising from electrostatic attraction interactions between the protonated amine groups of polylysine and carboxylic groups on the acid-oxidized multi-wall carbon nanotubes (Ox-MWCNTs) dominate the interaction at a low pH, weaker adhesion forces via the hydrogen bonding between the neutral -NH2 groups of polylysine and -COO- groups of the Ox-MWCNTs were detected at a high pH. The adhesion force was further found to increase with the oxidation time for Ox-MWCNTs and to be negligible for oxidized single-wall carbon nanotubes (Ox-SWCNTs) because carboxylate groups were only attached onto the nanotube tips in the latter whereas onto both the nanotube tips and sidewall in the former. Furthermore, it was demonstrated that proteins containing aromatic moieties, such as polytryptophan, showed a stronger adhesion force with Ox-MWCNTs than that of polylysine because of the additional pi-pi stacking interaction between the polytryptophan chains and CNTs.
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154
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Kramer RM, Crookes-Goodson WJ, Naik RR. The self-organizing properties of squid reflectin protein. NATURE MATERIALS 2007; 6:533-8. [PMID: 17546036 DOI: 10.1038/nmat1930] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Accepted: 05/02/2007] [Indexed: 05/15/2023]
Abstract
Reflectins, a recently identified protein family that is enriched in aromatic and sulphur-containing amino acids, are used by certain cephalopods to manage and manipulate incident light in their environment. These proteins are the predominant constituent of nanoscaled photonic structures that function in static and adaptive colouration, extending visual performance and intra-species communication. Our investigation into recombinantly expressed reflectin has revealed unanticipated self-assembling and behavioural properties, and we demonstrate that reflectin can be easily processed into thin films, photonic grating structures and fibres. Our findings represent a key step in our understanding of the property-function relationships of this unique family of reflective proteins.
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155
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Drummy LF, Farmer BL, Naik RR. Correlation of the β-sheet crystal size in silk fibers with the protein amino acid sequence. SOFT MATTER 2007; 3:877-882. [PMID: 32900081 DOI: 10.1039/b701220a] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Low voltage transmission electron microscopy (LVTEM) and wide angle X-ray scattering (WAXS) are used to independently determine the size of the β-sheet crystalline regions in Bombyx mori silk fibers. The peak in the size distributions of the major and minor axes of the anisotropic crystallites measured from the LVTEM images compare well with the average sizes as determined by Scherrer analysis of the X-ray fiber diagrams. These values are then discussed in the context of the B. mori fibroin heavy chain amino acid sequence, and the underlying mechanism for the organism's control on fiber crystallite size, and therefore mechanical properties, is proposed.
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156
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Tomczak MM, Slocik JM, Stone MO, Naik RR. Bio-based approaches to inorganic material synthesis. Biochem Soc Trans 2007; 35:512-5. [PMID: 17511641 DOI: 10.1042/bst0350512] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Nature is an exquisite designer of inorganic materials using biomolecules as templates. Diatoms create intricate silica wall structures with fine features using the protein family of silaffins as templates. Marine sponges create silica spicules also using proteins, termed silicateins. In recent years, our group and others have used biomolecules as templates for the deposition of inorganic materials. In contrast with the traditional materials science approach, which requires high heat, extreme pH and non-aqueous solutions, the bio-based approaches allow the reactions to proceed usually at near ambient conditions. Additionally, the biological templates allow for the control of the inorganic nanoparticle morphology. The use of peptides and biomolecules for templating and assembling inorganics will be discussed here.
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157
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Slocik JM, Tam F, Halas NJ, Naik RR. Peptide-assembled optically responsive nanoparticle complexes. NANO LETTERS 2007; 7:1054-8. [PMID: 17378619 DOI: 10.1021/nl070267x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The design of active nanostructures whose form and properties can be modulated by remote means is an important challenge in nanoscience. Here we report two types of active nanoparticle complexes, with properties controlled by near-infrared illumination, resulting from the assembly of photothermally responsive plasmonic nanoparticles with thermally labile biomolecular linkers. Au nanoshells (NS) and quantum dots (QD) are assembled using coiled-coil peptides into NS-NS and NS-QD complexes. Illumination of the NS-NS complexes results in reversible disassembly reassembly, while illumination of NS-QD complexes results in a large, reproducible modulation of the quantum dot fluorescence without disassembly of the nanoparticle-peptide complex.
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158
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Gupta MK, Khokhar SK, Phillips DM, Sowards LA, Drummy LF, Kadakia MP, Naik RR. Patterned silk films cast from ionic liquid solubilized fibroin as scaffolds for cell growth. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:1315-9. [PMID: 17241052 DOI: 10.1021/la062047p] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Silk is an attractive biomaterial for use in tissue engineering applications because of its slow degradation, excellent mechanical properties, and biocompatibility. In this report, we demonstrate a simple method to cast patterned films directly from silk fibroin dissolved in an ionic liquid. The films cast from the silk ionic liquid solution were found to support normal cell proliferation and differentiation. The versatility of the silk ionic liquid solutions and the ability to process large amounts of silk into materials with controlled surface topography directly from the dissolved silk ionic liquid solution could enhance the desirability of biomaterials such as silk for a variety of applications.
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159
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Patnaik SS, Trohalaki S, Naik RR, Stone MO, Pachter R. Computational study of the absorption spectra of green fluorescent protein mutants. Biopolymers 2007; 85:253-63. [PMID: 17206623 DOI: 10.1002/bip.20642] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this work, we present a theoretical study of the relationship between molecular structure and the red-shift in absorption spectra of S65G and S65T green fluorescent protein (GFP) mutants. To identify the effects of the protein environment, we combined results from molecular dynamics (MD) simulations and quantum mechanics/molecular mechanics calculations to obtain structural properties, and applied time-dependent density functional theory to calculate the excitation energies. By using results from the MD simulations, we were able to provide a systematic analysis of the structural details that may effect the red-shift in the absorption spectra when taking into account temperature effects. Furthermore, a detailed study of hydrogen bonding during the MD simulations demonstrated differences between S65G and S65T, for example, regarding hydrogen bonding with Glu222. An analysis of the absorption spectra for different forms of the chromophore emphasized the dominance of the anionic forms in solution for the S65G and S65T GFP mutants.
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160
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Kuncicky DM, Naik RR, Velev OD. Rapid deposition and long-range alignment of nanocoatings and arrays of electrically conductive wires from tobacco mosaic virus. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2006; 2:1462-6. [PMID: 17193007 DOI: 10.1002/smll.200600399] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
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161
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Wong Po Foo C, Patwardhan SV, Belton DJ, Kitchel B, Anastasiades D, Huang J, Naik RR, Perry CC, Kaplan DL. Novel nanocomposites from spider silk-silica fusion (chimeric) proteins. Proc Natl Acad Sci U S A 2006; 103:9428-33. [PMID: 16769898 PMCID: PMC1476692 DOI: 10.1073/pnas.0601096103] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Silica skeletal architectures in diatoms are characterized by remarkable morphological and nanostructural details. Silk proteins from spiders and silkworms form strong and intricate self-assembling fibrous biomaterials in nature. We combined the features of silk with biosilica through the design, synthesis, and characterization of a novel family of chimeric proteins for subsequent use in model materials forming reactions. The domains from the major ampullate spidroin 1 (MaSp1) protein of Nephila clavipes spider dragline silk provide control over structural and morphological details because it can be self-assembled through diverse processing methods including film casting and fiber electrospinning. Biosilica nanostructures in diatoms are formed in aqueous ambient conditions at neutral pH and low temperatures. The R5 peptide derived from the silaffin protein of Cylindrotheca fusiformis induces and regulates silica precipitation in the chimeric protein designs under similar ambient conditions. Whereas mineralization reactions performed in the presence of R5 peptide alone form silica particles with a size distribution of 0.5-10 microm in diameter, reactions performed in the presence of the new fusion proteins generate nanocomposite materials containing silica particles with a narrower size distribution of 0.5-2 microm in diameter. Furthermore, we demonstrate that composite morphology and structure could be regulated by controlling processing conditions to produce films and fibers. These results suggest that the chimeric protein provides new options for processing and control over silica particle sizes, important benefits for biomedical and specialty materials, particularly in light of the all aqueous processing and the nanocomposite features of these new materials.
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162
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Pender MJ, Sowards LA, Hartgerink JD, Stone MO, Naik RR. Peptide-mediated formation of single-wall carbon nanotube composites. NANO LETTERS 2006; 6:40-4. [PMID: 16402784 DOI: 10.1021/nl051899r] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The formation of silica- and titania-coated single-wall carbon nanotubes (SWNTs) using a mutlifunctional peptide to both suspend SWNTs and direct the precipitation of silica and titania at room temperature is demonstrated.
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163
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Rauch ME, Graef HW, Rozenzhak SM, Jones SE, Bleckmann CA, Kruger RL, Naik RR, Stone MO. Characterization of microbial contamination in United States Air Force aviation fuel tanks. J Ind Microbiol Biotechnol 2005; 33:29-36. [PMID: 16328508 DOI: 10.1007/s10295-005-0023-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2004] [Accepted: 07/20/2005] [Indexed: 11/30/2022]
Abstract
Bacteria and fungi, isolated from United States Air Force (USAF) aviation fuel samples, were identified by gas chromatograph fatty acid methyl ester (GC-FAME) profiling and 16S or 18S rRNA gene sequencing. Thirty-six samples from 11 geographically separated USAF bases were collected. At each base, an above-ground storage tank, a refueling truck, and an aircraft wing tank were sampled at the lowest sample point, or sump, to investigate microbial diversity and dispersion within the fuel distribution chain. Twelve genera, including four Bacillus species and two Staphylococcus species, were isolated and identified. Bacillus licheniformis, the most prevalent organism isolated, was found at seven of the 11 bases. Of the organisms identified, Bacillus sp., Micrococcus luteus, Sphinogmonas sp., Staphylococcus sp., and the fungus Aureobasidium pullulans have previously been isolated from aviation fuel samples. The bacteria Pantoea ananatis, Arthrobacter sp., Alcaligenes sp., Kocuria rhizophilia, Leucobacter komagatae, Dietza sp., and the fungus Discophaerina fagi have not been previously reported in USAF aviation fuel. Only at two bases were the same organisms isolated from all three sample points in the fuel supply distribution chain. Isolation of previously undocumented organisms suggests either, changes in aviation fuel microbial community in response to changes in aviation fuel composition, additives and biocide use, or simply, improvements in isolation and identification techniques.
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164
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Slocik JM, Stone MO, Naik RR. Synthesis of gold nanoparticles using multifunctional peptides. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2005; 1:1048-52. [PMID: 17193392 DOI: 10.1002/smll.200500172] [Citation(s) in RCA: 168] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
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165
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Drummy LF, Phillips DM, Stone MO, Farmer BL, Naik RR. Thermally Induced α-Helix to β-Sheet Transition in Regenerated Silk Fibers and Films. Biomacromolecules 2005; 6:3328-33. [PMID: 16283762 DOI: 10.1021/bm0503524] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The structure of thin films cast from regenerated solutions of Bombyx mori cocoon silk in hexafluoroisopropyl alcohol (HFIP) was studied by synchrotron X-ray diffraction during heating. A solid-state conformational transition from an alpha-helical structure to the well-known beta-sheet silk II structure occurred at a temperature of approximately 140 degrees C. The transition appeared to be homogeneous, as both phases do not coexist within the resolution of the current study. Modulated differential scanning calorimetry (DSC) of the films showed an endothermic melting peak followed by an exothermic crystallization peak, both occurring near 140 degrees C. Oriented fibers were also produced that displayed this helical molecular conformation. Subsequent heating above the structural transition temperature produced oriented beta-sheet fibers very similar in structure to B. mori cocoon fibers. Heat treatment of silk films at temperatures well below their degradation temperature offers a controllable route to materials with well-defined structures and mechanical behavior.
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166
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Kramer RM, Sowards LA, Pender MJ, Stone MO, Naik RR. Constrained iron catalysts for single-walled carbon nanotube growth. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:8466-70. [PMID: 16114958 DOI: 10.1021/la0506729] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The diameter of single walled carbon nanotubes (SWNTs) determines the electronic properties of the nanotube. The diameter of carbon nanotubes is dictated by the diameter of the catalyst particle. Here we describe the use of iron nanoparticles synthesized within the Dps protein cage as catalysts for the growth of single-walled carbon nanotubes. The discrete iron particles synthesized within the Dps protein cages when used as catalyst particles gives rise to single-walled carbon nanotubes with a limited diameter distribution.
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167
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Tomczak MM, Glawe DD, Drummy LF, Lawrence CG, Stone MO, Perry CC, Pochan DJ, Deming TJ, Naik RR. Polypeptide-Templated Synthesis of Hexagonal Silica Platelets. J Am Chem Soc 2005; 127:12577-82. [PMID: 16144405 DOI: 10.1021/ja0524503] [Citation(s) in RCA: 198] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several studies have demonstrated the use of biomimetic approaches in the synthesis of a variety of inorganic materials. Poly-L-lysine (PLL) promotes the precipitation of silica from a silicic acid solution within minutes. The molecular weight of PLL was found to affect the morphology of the resulting silica precipitate. Larger-molecular weight PLL produced hexagonal silica platelets, whereas spherical silica particles were obtained using low-molecular weight PLL. Here we report on the polypeptide secondary-structure transition that occurs during the silicification reaction. The formation of the hexagonal silica platelets is attributed to the PLL helical chains that are formed in the presence of monosilicic acid and phosphate ions. Hexagonal PLL crystals can also serve as templates in directing the growth of the silica in a manner that generates a largely mesoporous silica phase that is oriented with respect to the protein crystal template.
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168
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Kramer RM, Li C, Carter DC, Stone MO, Naik RR. Engineered protein cages for nanomaterial synthesis. J Am Chem Soc 2005; 126:13282-6. [PMID: 15479082 DOI: 10.1021/ja046735b] [Citation(s) in RCA: 193] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Self-assembled particles of genetically engineered human L subunit ferritin expressing a silver-binding peptide were used as nanocontainers for the synthesis of silver nanoparticles. The inner cavity of the self-assembled protein cage displays a dodecapeptide that is capable of reducing silver ions to metallic silver. This chimeric protein cage when incubated in the presence of silver nitrate exhibits the growth of a silver nanocrystal within its cavity. Our studies indicate that it is possible to design chimeric cages, using specific peptide templates, for the growth of other inorganic nanoparticles.
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169
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Rozenzhak SM, Kadakia MP, Caserta TM, Westbrook TR, Stone MO, Naik RR. Cellular internalization and targeting of semiconductor quantum dots. Chem Commun (Camb) 2005:2217-9. [PMID: 15856101 DOI: 10.1039/b418454h] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Peptide-mediated internalization and organelle targeting of quantum dots.
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170
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Glawe DD, Rodríguez F, Stone MO, Naik RR. Polypeptide-mediated silica growth on indium tin oxide surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:717-720. [PMID: 15641845 DOI: 10.1021/la047964e] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Herein, we describe the formation of silica structures on indium tin oxide (ITO) surfaces using poly-L-lysine (PLL) to template the condensation of silicic acid. Precisely controlled electrostatic fields were used to preposition PLL onto ITO surfaces. Subsequent polypeptide-mediated silicification resulted in the formation of silica with concentration gradients that followed the pattern of the externally applied electrostatic field used in the deposition of the PLL. The resulting silica structures were securely attached to the ITO surface. The technique described here offers an inexpensive and rapid method for the deposition of polypeptides on surfaces.
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171
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Slocik JM, Naik RR, Stone MO, Wright DW. Viral templates for gold nanoparticle synthesis. ACTA ACUST UNITED AC 2005. [DOI: 10.1039/b413074j] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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172
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Phillips DM, Drummy LF, Naik RR, Long HCD, Fox DM, Trulove PC, Mantz RA. Regenerated silk fiber wet spinning from an ionic liquid solution. ACTA ACUST UNITED AC 2005. [DOI: 10.1039/b510069k] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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173
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Dickerson MB, Naik RR, Sarosi PM, Agarwal G, Stone MO, Sandhage KH. Ceramic nanoparticle assemblies with tailored shapes and tailored chemistries via biosculpting and shape-preserving inorganic conversion. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2005; 5:63-67. [PMID: 15762162 DOI: 10.1166/jnn.2005.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A novel biosynthetic paradigm is introduced for fabricating three-dimensional (3-D) ceramic nanoparticle assemblies with tailored shapes and tailored chemistries: biosculpting and shape-preserving inorganic conversion (BaSIC). Biosculpting refers to the use of biomolecules that direct the precipitation of ceramic nanoparticles to form a continuous 3-D structure with a tailored shape. We used a peptide derived from a diatom (a type of unicellular algae) to biosculpt silica nanoparticle based assemblies that, in turn, were converted into a new (nonsilica) composition via a shape-preserving gas/silica displacement reaction. Interwoven, microfilamentary silica structures were prepared by exposing a peptide, derived from the silaffin-1A protein of the diatom Cylindrotheca fusiformis, to a tetramethylorthosilicate solution under a linear shear flow condition. Subsequent exposure of the silica microfilaments to magnesium gas at 900 degrees C resulted in conversion into nanocrystalline magnesium oxide microfilaments with a retention of fine (submicrometer) features. Fluid(gas or liquid)/silica displacement reactions leading to a variety of other oxides have also been identified. This hybrid (biogenic/synthetic) approach opens the door to biosculpted ceramic microcomponents with multifarious tailored shapes and compositions for a wide range of environmental, aerospace, biomedical, chemical, telecommunications, automotive, manufacturing, and defense applications.
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174
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Putthanarat S, Eby R, Naik RR, Juhl SB, Walker MA, Peterman E, Ristich S, Magoshi J, Tanaka T, Stone MO, Farmer B, Brewer C, Ott D. Nonlinear optical transmission of silk/green fluorescent protein (GFP) films. POLYMER 2004. [DOI: 10.1016/j.polymer.2004.10.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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175
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Phillips DM, Drummy LF, Conrady DG, Fox DM, Naik RR, Stone MO, Trulove PC, De Long HC, Mantz RA. Dissolution and Regeneration of Bombyx mori Silk Fibroin Using Ionic Liquids. J Am Chem Soc 2004; 126:14350-1. [PMID: 15521743 DOI: 10.1021/ja046079f] [Citation(s) in RCA: 264] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this work, the suitability of imidazolium-based ionic liquid solvents is investigated for the dissolution and regeneration of silkworm (Bombyx mori) silk. Within an ionic liquid the anion plays a larger role in dictating the ultimate solubility of the silk. The dissolution of the silk in the ionic liquid is confirmed using wide-angle X-ray scattering. The dissolved silk is also processed into 100 mum-thick, two-dimensional films, and the structure of these films is examined. The rinse solvent, acetonitrile or methanol, has a profound impact on both the topography of the films and the secondary structure of the silk protein. The image depicts a silkworm cocoon dissolved in 1-butyl-3-methylimidazolium chloride and then regenerated as a film with birefringence.
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