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Sotnikov SV, Markt PO, Malik V, Chekmareva NY, Naik RR, Sah A, Singewald N, Holsboer F, Czibere L, Landgraf R. Bidirectional rescue of extreme genetic predispositions to anxiety: impact of CRH receptor 1 as epigenetic plasticity gene in the amygdala. Transl Psychiatry 2014; 4:e359. [PMID: 24518397 PMCID: PMC3944631 DOI: 10.1038/tp.2013.127] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Accepted: 12/07/2013] [Indexed: 12/05/2022] Open
Abstract
The continuum of physiological anxiety up to psychopathology is not merely dependent on genes, but is orchestrated by the interplay of genetic predisposition, gene x environment and epigenetic interactions. Accordingly, inborn anxiety is considered a polygenic, multifactorial trait, likely to be shaped by environmentally driven plasticity at the genomic level. We here took advantage of the extreme genetic predisposition of the selectively bred high (HAB) and low anxiety (LAB) mouse model exhibiting high vs low anxiety-related behavior and tested whether and how beneficial (enriched environment) vs detrimental (chronic mild stress) environmental manipulations are capable of rescuing phenotypes from both ends of the anxiety continuum. We provide evidence that (i) even inborn and seemingly rigid behavioral and neuroendocrine phenotypes can bidirectionally be rescued by appropriate environmental stimuli, (ii) corticotropin-releasing hormone receptor 1 (Crhr1), critically involved in trait anxiety, shows bidirectional alterations in its expression in the basolateral amygdala (BLA) upon environmental stimulation, (iii) these alterations are linked to an increased methylation status of its promoter and, finally, (iv) binding of the transcription factor Yin Yang 1 (YY1) to the Crhr1 promoter contributes to its gene expression in a methylation-sensitive manner. Thus, Crhr1 in the BLA is critically involved as plasticity gene in the bidirectional epigenetic rescue of extremes in trait anxiety.
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Vasudev MC, Koerner H, Singh KM, Partlow BP, Kaplan DL, Gazit E, Bunning TJ, Naik RR. Vertically Aligned Peptide Nanostructures Using Plasma-Enhanced Chemical Vapor Deposition. Biomacromolecules 2014; 15:533-40. [DOI: 10.1021/bm401491k] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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78
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Zahran EM, Bedford NM, Nguyen MA, Chang YJ, Guiton BS, Naik RR, Bachas LG, Knecht MR. Light-Activated Tandem Catalysis Driven by Multicomponent Nanomaterials. J Am Chem Soc 2013; 136:32-5. [DOI: 10.1021/ja410465s] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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79
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Cung K, Han BJ, Nguyen TD, Mao S, Yeh YW, Xu S, Naik RR, Poirier G, Yao N, Purohit PK, McAlpine MC. Biotemplated synthesis of PZT nanowires. NANO LETTERS 2013; 13:6197-6202. [PMID: 24274657 DOI: 10.1021/nl4035708] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Piezoelectric nanowires are an important class of smart materials for next-generation applications including energy harvesting, robotic actuation, and bioMEMS. Lead zirconate titanate (PZT), in particular, has attracted significant attention, owing to its superior electromechanical conversion performance. Yet, the ability to synthesize crystalline PZT nanowires with well-controlled properties remains a challenge. Applications of common nanosynthesis methods to PZT are hampered by issues such as slow kinetics, lack of suitable catalysts, and harsh reaction conditions. Here we report a versatile biomimetic method, in which biotemplates are used to define PZT nanostructures, allowing for rational control over composition and crystallinity. Specifically, stoichiometric PZT nanowires were synthesized using both polysaccharide (alginate) and bacteriophage templates. The wires possessed measured piezoelectric constants of up to 132 pm/V after poling, among the highest reported for PZT nanomaterials. Further, integrated devices can generate up to 0.820 μW/cm(2) of power. These results suggest that biotemplated piezoelectric nanowires are attractive candidates for stimuli-responsive nanosensors, adaptive nanoactuators, and nanoscale energy harvesters.
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Dickerson MB, Fillery SP, Koerner H, Singh KM, Martinick K, Drummy LF, Durstock MF, Vaia RA, Omenetto FG, Kaplan DL, Naik RR. Dielectric Breakdown Strength of Regenerated Silk Fibroin Films as a Function of Protein Conformation. Biomacromolecules 2013; 14:3509-14. [DOI: 10.1021/bm4008452] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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81
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Akdim B, Pachter R, Kim SS, Naik RR, Walsh TR, Trohalaki S, Hong G, Kuang Z, Farmer BL. Electronic properties of a graphene device with peptide adsorption: insight from simulation. ACS APPLIED MATERIALS & INTERFACES 2013; 5:7470-7477. [PMID: 23869852 DOI: 10.1021/am401731c] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this work, to explain doping behavior of single-layer graphene upon HSSYWYAFNNKT (P1) and HSSAAAAFNNKT (P1-3A) adsorption in field-effect transistors (GFETs), we applied a combined computational approach, whereby peptide adsorption was modeled by molecular dynamics simulations, and the lowest energy configuration was confirmed by density functional theory calculations. On the basis of the resulting structures of the hybrid materials, electronic structure and transport calculations were investigated. We demonstrate that π-π stacking of the aromatic residues and proximate peptide backbone to the graphene surface in P1 have a role in the p-doping. These results are consistent with our experimental observation of the GFET's p-doping even after a 24-h annealing procedure. Upon substitution of three of the aromatic residues to Ala in (P1-3A), a considerable decrease from p-doping is observed experimentally, demonstrating n-doping as compared to the nonadsorbed device, yet not explained based on the atomistic MD simulation structures. To gain a qualitative understanding of P1-3A's adsorption over a longer simulation time, which may differ from aromatic amino acid residues' swift anchoring on the surface, we analyzed equilibrated coarse-grain simulations performed for 500 ns. Desorption of the Ala residues from the surface was shown computationally, which could in turn affect charge transfer, yet a full explanation of the mechanism of n-doping will require elucidation of differences between various aromatic residues as dependent on peptide composition, and inclusion of effects of the substrate and environment, to be considered in future work.
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82
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Puddu V, Slocik JM, Naik RR, Perry CC. Titania binding peptides as templates in the biomimetic synthesis of stable titania nanosols: insight into the role of buffers in peptide-mediated mineralization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:9464-9472. [PMID: 23815089 DOI: 10.1021/la401777x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this Article, we report the unusual behavior of two peptides (Ti-1 (QPYLFATDSLIK) and Ti-2 (GHTHYHAVRTQT)) with high affinity for titania that efficiently promote titania mineralization from an aqueous titanium bisammonium lactatodihydroxide (TiBALDH) solution, yielding small (ca. 4 nm) titania nanoparticles. As a result, we were able to produce for the first time using a biomimetic approach highly stable sub-10-nm titania sols. Both sequences show a high titania mineralization activity per unit peptide concentration and a capacity to control particle size and stabilize nanoparticles through specific surface interactions. We also show that phosphate ions disrupt the controlled particle formation and stabilization achieved in the presence of the two peptides. The products obtained from phosphate buffered solutions are titanium-containing materials (not pure oxide) with poor morphological control similar to those previously reported by others. Our results provide important insights into understanding the mechanism of titania mineralization in a range of different aqueous media (water, Tris, and phosphate buffer).
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83
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Coppage R, Slocik JM, Ramezani-Dakhel H, Bedford NM, Heinz H, Naik RR, Knecht MR. Exploiting Localized Surface Binding Effects to Enhance the Catalytic Reactivity of Peptide-Capped Nanoparticles. J Am Chem Soc 2013; 135:11048-54. [DOI: 10.1021/ja402215t] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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84
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Slocik JM, Crouse CA, Spowart JE, Naik RR. Biologically tunable reactivity of energetic nanomaterials using protein cages. NANO LETTERS 2013; 13:2535-2540. [PMID: 23713514 DOI: 10.1021/nl400590k] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The performance of aluminum nanomaterial based energetic formulations is dependent on the mass transport, diffusion distance, and stability of reactive components. Here we use a biologically inspired approach to direct the assembly of oxidizer loaded protein cages onto the surface of aluminum nanoparticles to improve reaction kinetics by reducing the diffusion distance between the reactants. Ferritin protein cages were loaded with ammonium perchlorate (AP) or iron oxide and assembled with nAl to create an oxidation-reduction based energetic reaction and the first demonstration of a nanoscale biobased thermite material. Both materials showed enhanced exothermic behavior in comparison to nanothermite mixtures of bulk free AP or synthesized iron oxide nanopowders prepared without the use of ferritin. In addition, by utilizing a layer-by-layer (LbL) process to build multiple layers of protein cages containing iron oxide and iron oxide/AP on nAl, stoichiometric conditions and energetic performance can be optimized.
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85
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Kim SS, Hisey CL, Kuang Z, Comfort DA, Farmer BL, Naik RR. The effect of single wall carbon nanotube metallicity on genomic DNA-mediated chirality enrichment. NANOSCALE 2013; 5:4931-4936. [PMID: 23624632 DOI: 10.1039/c3nr00458a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Achieving highly enriched single wall carbon nanotubes (SWNTs) is one of the major hurdles today because their chirality-dependent properties must be uniform and predictable for use in nanoscale electronics. Due to the unique wrapping and groove-binding mechanism, DNA has been demonstrated as a highly specific SWNT dispersion and fractionation agent, with its enrichment capabilities depending on the DNA sequence and length as well as the nanotube properties. Salmon genomic DNA (SaDNA) offers an inexpensive and scalable alternative to synthetic DNA. In this study, SaDNA enrichment capabilities were tested on SWNT separation with varying degrees of metallicity that were formulated from mixtures of commercial metallic (met-) and semiconducting (sem-) abundant SWNTs. The results herein demonstrate that the degree of metallicity of the SWNT sample has a significant effect on the SaDNA enrichment capabilities, and this effect is modeled based on deconvolution of the near-infrared (NIR) absorption spectra and verified with photoluminescence emission (PLE) measurements. Using molecular dynamics and circular dichroism, the preferential SaDNA mediated separation of the (6, 5) sem-tube is shown to be largely influenced by the presence of met-SWNTs.
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86
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Vasudev MC, Anderson KD, Bunning TJ, Tsukruk VV, Naik RR. Exploration of plasma-enhanced chemical vapor deposition as a method for thin-film fabrication with biological applications. ACS APPLIED MATERIALS & INTERFACES 2013; 5:3983-94. [PMID: 23668863 DOI: 10.1021/am302989x] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Chemical vapor deposition (CVD) has been used historically for the fabrication of thin films composed of inorganic materials. But the advent of specialized techniques such as plasma-enhanced chemical vapor deposition (PECVD) has extended this deposition technique to various monomers. More specifically, the deposition of polymers of responsive materials, biocompatible polymers, and biomaterials has made PECVD attractive for the integration of biotic and abiotic systems. This review focuses on the mechanisms of thin-film growth using low-pressure PECVD and current applications of classic PECVD thin films of organic and inorganic materials in biological environments. The last part of the review explores the novel application of low-pressure PECVD in the deposition of biological materials.
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87
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Mannoor MS, Tao H, Clayton JD, Sengupta A, Kaplan DL, Naik RR, Verma N, Omenetto FG, McAlpine MC. Erratum: Corrigendum: Graphene-based wireless bacteria detection on tooth enamel. Nat Commun 2013. [DOI: 10.1038/ncomms2843] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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88
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Abbas A, Brimer A, Slocik JM, Tian L, Naik RR, Singamaneni S. Multifunctional analytical platform on a paper strip: separation, preconcentration, and subattomolar detection. Anal Chem 2013; 85:3977-83. [PMID: 23425068 DOI: 10.1021/ac303567g] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We report a plasmonic paper-based analytical platform with functional versatility and subattomolar (<10(-18) M) detection limit using surface-enhanced Raman scattering as a transduction method. The microfluidic paper-based analytical device (μPAD) is made with a lithography-free process by a simple cut and drop method. Complex samples are separated by a surface chemical gradient created by differential polyelectrolyte coating of the paper. The μPAD with a starlike shape is designed to enable liquid handling by lateral flow without microchannel patterning. This design generates a rapid capillary-driven flow capable of dragging liquid samples as well as gold nanorods into a single cellulose microfiber, thereby providing an extremely preconcentrated and optically active detection spot.
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89
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Dickerson MB, Sierra AA, Bedford NM, Lyon WJ, Gruner WE, Mirau PA, Naik RR. Keratin-based antimicrobial textiles, films, and nanofibers. J Mater Chem B 2013; 1:5505-5514. [DOI: 10.1039/c3tb20896f] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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90
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Nergiz SZ, Slocik JM, Naik RR, Singamaneni S. Surface defect sites facilitate fibrillation: an insight into adsorption of gold-binding peptides on Au(111). Phys Chem Chem Phys 2013; 15:11629-33. [DOI: 10.1039/c3cp50972a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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91
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Ramezani-Dakhel H, Mirau PA, Naik RR, Knecht MR, Heinz H. Stability, surface features, and atom leaching of palladium nanoparticles: toward prediction of catalytic functionality. Phys Chem Chem Phys 2013; 15:5488-92. [DOI: 10.1039/c3cp00135k] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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92
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Nagraj N, Slocik JM, Phillips DM, Kelley-Loughnane N, Naik RR, Potyrailo RA. Selective sensing of vapors of similar dielectric constants using peptide-capped gold nanoparticles on individual multivariable transducers. Analyst 2013; 138:4334-9. [DOI: 10.1039/c3an00088e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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93
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Kreit E, Mäthger LM, Hanlon RT, Dennis PB, Naik RR, Forsythe E, Heikenfeld J. Biological versus electronic adaptive coloration: how can one inform the other? J R Soc Interface 2012; 10:20120601. [PMID: 23015522 DOI: 10.1098/rsif.2012.0601] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Adaptive reflective surfaces have been a challenge for both electronic paper (e-paper) and biological organisms. Multiple colours, contrast, polarization, reflectance, diffusivity and texture must all be controlled simultaneously without optical losses in order to fully replicate the appearance of natural surfaces and vividly communicate information. This review merges the frontiers of knowledge for both biological adaptive coloration, with a focus on cephalopods, and synthetic reflective e-paper within a consistent framework of scientific metrics. Currently, the highest performance approach for both nature and technology uses colourant transposition. Three outcomes are envisioned from this review: reflective display engineers may gain new insights from millions of years of natural selection and evolution; biologists will benefit from understanding the types of mechanisms, characterization and metrics used in synthetic reflective e-paper; all scientists will gain a clearer picture of the long-term prospects for capabilities such as adaptive concealment and signaling.
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94
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Qin G, Dennis PB, Zhang Y, Hu X, Bressner JE, Sun Z, Crookes-Goodson WJ, Naik RR, Omenetto FG, Kaplan DL. Recombinant reflectin-based optical materials. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/polb.23204] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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95
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Potyrailo RA, Nagraj N, Surman C, Boudries H, Lai H, Slocik JM, Kelley-Loughnane N, Naik RR. Wireless sensors and sensor networks for homeland security applications. Trends Analyt Chem 2012; 40:133-145. [PMID: 23175590 DOI: 10.1016/j.trac.2012.07.013] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
New sensor technologies for homeland security applications must meet the key requirements of sensitivity to detect agents below risk levels, selectivity to provide minimal false-alarm rates, and response speed to operate in high throughput environments, such as airports, sea ports, and other public places. Chemical detection using existing sensor systems is facing a major challenge of selectivity. In this review, we provide a brief summary of chemical threats of homeland security importance; focus in detail on modern concepts in chemical sensing; examine the origins of the most significant unmet needs in existing chemical sensors; and, analyze opportunities, specific requirements, and challenges for wireless chemical sensors and wireless sensor networks (WSNs). We further review a new approach for selective chemical sensing that involves the combination of a sensing material that has different response mechanisms to different species of interest, with a transducer that has a multi-variable signal-transduction ability. This new selective chemical-sensing approach was realized using an attractive ubiquitous platform of battery-free passive radio-frequency identification (RFID) tags adapted for chemical sensing. We illustrate the performance of RFID sensors developed in measurements of toxic industrial materials, humidity-independent detection of toxic vapors, and detection of chemical-agent simulants, explosives, and strong oxidizers.
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96
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Dennis PB, Walker AY, Dickerson MB, Kaplan DL, Naik RR. Stabilization of organophosphorus hydrolase by entrapment in silk fibroin: formation of a robust enzymatic material suitable for surface coatings. Biomacromolecules 2012; 13:2037-45. [PMID: 22651251 DOI: 10.1021/bm300358g] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Organophosphates are some of the most acutely toxic compounds synthesized on an industrial scale, and organophosphorus hydrolase (OPH) has the ability to hydrolyze and inactivate a number of these chemicals. However, OPH activity is vulnerable to harsh environmental conditions that would accompany its practical utility in the field; a limitation that can also be extended to conditions required for incorporation of OPH into useful materials. Here we present evidence that entrapment of OPH in silk fibroin leads to stabilization of OPH activity under a variety of conditions that would otherwise reduce free enzyme activity, such as elevated temperature, UV light exposure and the presence of detergent. Silk fibroin entrapment of OPH also allowed for its dispersal into a polyurethane-based coating that retained organophosphate hydrolysis activity after formulation, application and drying. Together, the data presented here demonstrate the utility of silk fibroin entrapment for the protection of OPH activity under a variety of environmental conditions.
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Abstract
The development of a miniaturized sensing platform tailored for sensitive and selective detection of a variety of biochemical analytes could offer transformative fundamental and technological opportunities. Due to their high surface-to-volume ratios, nanoscale materials are extremely sensitive sensors. Likewise, peptides represent robust substrates for selective recognition due to the potential for broad chemical diversity within their relatively compact size. Here we explore the possibilities of linking peptides to nanosensors for the selective detection of biochemical targets. Such systems raise a number of interesting fundamental challenges: What are the peptide sequences, and how can rational design be used to derive selective binders? What nanomaterials should be used, and what are some strategies for assembling hybrid nanosensors? What role does molecular modeling play in elucidating response mechanisms? What is the resulting performance of these sensors, in terms of sensitivity, selectivity, and response time? What are some potential applications? This Account will highlight our early attempts to address these research challenges. Specifically, we use natural peptide sequences or sequences identified from phage display as capture elements. The sensors are based on a variety of nanomaterials including nanowires, graphene, and carbon nanotubes. We couple peptides to the nanomaterial surfaces via traditional surface functionalization methods or self-assembly. Molecular modeling provides detailed insights into the hybrid nanostructure, as well as the sensor detection mechanisms. The peptide nanosensors can distinguish chemically camouflaged mixtures of vapors and detect chemical warfare agents with sensitivities as low as parts-per-billion levels. Finally, we anticipate future uses of this technology in biomedicine: for example, devices based on these sensors could detect disease from the molecular components in human breath. Overall, these results provide a novel platform for the development of highly sensitive and selective "nanoelectronic noses".
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98
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Katoch J, Kim SN, Kuang Z, Farmer BL, Naik RR, Tatulian SA, Ishigami M. Structure of a peptide adsorbed on graphene and graphite. NANO LETTERS 2012; 12:2342-2346. [PMID: 22471315 DOI: 10.1021/nl300286k] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Noncovalent functionalization of graphene using peptides is a promising method for producing novel sensors with high sensitivity and selectivity. Here we perform atomic force microscopy, Raman spectroscopy, infrared spectroscopy, and molecular dynamics simulations to investigate peptide-binding behavior to graphene and graphite. We studied a dodecamer peptide identified with phage display to possess affinity for graphite. Optical spectroscopy reveals that the peptide forms secondary structures both in powder form and in an aqueous medium. The dominant structure in the powder form is α-helix, which undergoes a transition to a distorted helical structure in aqueous solution. The peptide forms a complex reticular structure upon adsorption on graphene and graphite, having a helical conformation different from α-helix due to its interaction with the surface. Our observation is consistent with our molecular dynamics calculations, and our study paves the way for rational functionalization of graphene using biomolecules with defined structures and, therefore, functionalities.
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99
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Akdim B, Pachter R, Day PN, Kim SS, Naik RR. On modeling biomolecular-surface nonbonded interactions: application to nucleobase adsorption on single-wall carbon nanotube surfaces. NANOTECHNOLOGY 2012; 23:165703. [PMID: 22460916 DOI: 10.1088/0957-4484/23/16/165703] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In this work we explored the selectivity of single nucleobases towards adsorption on chiral single-wall carbon nanotubes (SWCNTs) by density functional theory calculations. Specifically, the adsorption of molecular models of guanine (G), adenine (A), thymine (T), and cytosine (C), as well as of AT and GC Watson-Crick (WC) base pairs on chiral SWCNT C(6, 5), C(9, 1) and C(8, 3) model structures, was analyzed in detail. The importance of correcting the exchange-correlation functional for London dispersion was clearly demonstrated, yet limitations in modeling such interactions by considering the SWCNT as a molecular model may mask subtle effects in a molecular-macroscopic material system. The trend in the calculated adsorption energies of the nucleobases on same diameter C(6, 5) and C(9, 1) SWCNT surfaces, i.e., G > A > T > C, was consistent with related computations and experimental work on graphitic surfaces, however contradicting experimental data on the adsorption of single-strand short homo-oligonucleotides on SWCNTs that demonstrated a trend of G > C > A > T (Albertorio et al 2009 Nanotechnology 20 395101). A possible role of electrostatic interactions in this case was partially captured by applying the effective fragment potential method, emphasizing that the interplay of the various contributions in modeling nonbonded interactions is complicated by theoretical limitations. Finally, because the calculated adsorption energies for Watson-Crick base pairs have shown little effect upon adsorption of the base pair farther from the surface, the results on SWCNT sorting by salmon genomic DNA could be indicative of partial unfolding of the double helix upon adsorption on the SWCNT surface.
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100
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Feng J, Slocik JM, Sarikaya M, Naik RR, Farmer BL, Heinz H. Influence of the shape of nanostructured metal surfaces on adsorption of single peptide molecules in aqueous solution. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2012; 8:1049-1059. [PMID: 22323430 DOI: 10.1002/smll.201102066] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Indexed: 05/31/2023]
Abstract
Self-assembly and function of biologically modified metal nanostructures depend on surface-selective adsorption; however, the influence of the shape of metal surfaces on peptide adsorption mechanisms has been poorly understood. The adsorption of single peptide molecules in aqueous solution (Tyr(12) , Ser(12) , A3, Flg-Na(3) ) is investigated on even {111} surfaces, stepped surfaces, and a 2 nm cuboctahedral nanoparticle of gold using molecular dynamics simulation with the CHARMM-METAL force field. Strong and selective adsorption is found on even surfaces and the inner edges of stepped surfaces (-20 to -60 kcal/mol peptide) in contrast to weaker and less selective adsorption on small nanoparticles (-15 to -25 kcal/mol peptide). Binding and selectivity appear to be controlled by the size of surface features and the extent of co-ordination of epitaxial sites by polarizable atoms (N, O, C) along the peptide chain. The adsorption energy of a single peptide equals a fraction of the sum of the adsorption energies of individual amino acids that is characteristic of surface shape, epitaxial pattern, and conformation constraints (often β-strand and random coil). The proposed adsorption mechanism is supported and critically evaluated by earlier sequence data from phage display, dissociation constants of small proteins as a function of nanoparticle size, and observed shapes of peptide-stabilized nanoparticles. Understanding the interaction of single peptides with shaped metal surfaces is a key step towards control over self-organization of multiple peptides on shaped metal surfaces and the assembly of superstructures from nanostructures.
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