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Ma X, Song H, Yan J. Electrochemically mediated gradient metallic film generation. NEW J CHEM 2021. [DOI: 10.1039/d1nj00030f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Metallic films with a controlled gradient can be fabricated on substrates via electrochemically induced metallic ion deposition.
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Affiliation(s)
- Xiaoqian Ma
- Key Laboratory of Energy Materials Chemistry
- Ministry of Education
- Key Laboratory of Advanced Functional Materials
- Autonomous Region
- Institute of Applied Chemistry
| | - Huan Song
- Key Laboratory of Energy Materials Chemistry
- Ministry of Education
- Key Laboratory of Advanced Functional Materials
- Autonomous Region
- Institute of Applied Chemistry
| | - Junfeng Yan
- Key Laboratory of Energy Materials Chemistry
- Ministry of Education
- Key Laboratory of Advanced Functional Materials
- Autonomous Region
- Institute of Applied Chemistry
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Nakamura S, Mitomo H, Sekizawa Y, Higuchi T, Matsuo Y, Jinnai H, Ijiro K. Strategy for Finely Aligned Gold Nanorod Arrays Using Polymer Brushes as a Template. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:3590-3599. [PMID: 32049537 DOI: 10.1021/acs.langmuir.9b03835] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The development of a strategy for the assembly of nanoscale building blocks, in particular, anisotropic nanoparticles, into desired structures is important for the construction of functional materials and devices. However, control over the orientation of rod-shaped nanoparticles on a substrate for integration into solid-state devices remains challenging. Here, we report a strategy for the fabrication of finely aligned gold nanorod (GNR) arrays using polymer (DNA) brushes as a nanoscale template. The gold nanorods modified with cationic surface ligands were electrostatically adsorbed onto the DNA brush substrates under various conditions. The orientational behavior of the GNRs was examined by spectral analyses and transmission electron microtomography (TEMT). As a result, we found several important factors, such as moderate interaction between GNRs and polymers and polymer densities on the substrate, related to the vertical alignment of GNRs on the substrates. We also developed a purification method to remove the undesired adsorption of GNRs onto the arrays. Finally, we have succeeded in the fabrication of extensive vertical GNR arrays of high quality via the easy bottom-up process.
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Affiliation(s)
- Satoshi Nakamura
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-Ku, Sapporo 060-8628, Japan
| | - Hideyuki Mitomo
- Research Institute for Electronic Science, Hokkaido University, Kita 21, Nishi 10, Kita-Ku, Sapporo 001-0021, Japan
- Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Kita 21, Nishi 11, Kita-Ku, Sapporo 001-0021, Japan
| | - Yu Sekizawa
- Graduate School of Life Sciences, Hokkaido University, Kita 10, Nishi 8, Kita-Ku, Sapporo 060-0810, Japan
| | - Takeshi Higuchi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Yasutaka Matsuo
- Research Institute for Electronic Science, Hokkaido University, Kita 21, Nishi 10, Kita-Ku, Sapporo 001-0021, Japan
| | - Hiroshi Jinnai
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Kuniharu Ijiro
- Research Institute for Electronic Science, Hokkaido University, Kita 21, Nishi 10, Kita-Ku, Sapporo 001-0021, Japan
- Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Kita 21, Nishi 11, Kita-Ku, Sapporo 001-0021, Japan
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Bracha D, Karzbrun E, Daube SS, Bar-Ziv RH. Emergent properties of dense DNA phases toward artificial biosystems on a surface. Acc Chem Res 2014; 47:1912-21. [PMID: 24856257 DOI: 10.1021/ar5001428] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
CONSPECTUS: The expression of genes in a cell in response to external signals or internal programs occurs within an environment that is compartmentalized and dense. Reconstituting gene expression in man-made systems is relevant for the basic understanding of gene regulation, as well as for the development of applications in bio- and nanotechnology. DNA polymer brushes assembled on a surface emulate a dense cellular environment. In a regime of significant chain overlap, the highly charged nature of DNA, its entropic degrees of freedom, and its interaction with transcription/translation machinery lead to emergent collective biophysical and biochemical properties, which are summarized in this Account. First, we describe a single-step photolithographic biochip on which biomolecules can be immobilized. Then, we present the assembly of localized DNA brushes, a few kilo-base pairs long, with spatially varying density, reaching a DNA concentration of ∼10(7) base pairs/μm(3), which is comparable to the value in E. coli. We then summarize the response of brush height to changes in density and mono- and divalent ionic strength. The balance between entropic elasticity and swelling forces leads to a rich phase behavior. At no added salt, polymers are completely stretched due to the osmotic pressure of ions, and at high salt they assume a relaxed coil conformation. Midrange, the brush height scales with ratio of density and ionic strength to the third power, in agreement with the general theory of polyelectrolyte brushes. In response to trivalent cations, DNA brushes collapse into macroscopic dendritic condensates with hysteresis, coexistence, and a hierarchy of condensation with brush density. We next present an investigation of RNA transcription in the DNA brush. In general, the brush density entropically excludes macromolecules, depleting RNA polymerase concentration in the brush compared to the bulk, therefore reducing transcription rate. The orientation of transcription promoters with respect to the surface also affects the rate with a lower value for outward compared to inward transcription, likely due to local changes of RNA polymerase concentrations. We hypothesize that equalizing the macromolecular osmotic pressure between bulk and brush with the addition of inert macromolecules would overcome the entropic exclusion of DNA associated proteins, and lead to enhanced biochemical activity. Finally, we present protein synthesis cascades in DNA brushes patterned at close proximity, as a step toward biochemical signaling between brushes. Examining the synthesis of proteins polymerizing into crystalline tubes suggests that on-chip molecular traps serve as nucleation sites for protein assembly, thereby opening possibilities for reconstituting nanoscale protein assembly pathways.
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Affiliation(s)
- Dan Bracha
- Department of Materials and
Interfaces Weizmann Institute of Science, Rehovot 76100, Israel
| | - Eyal Karzbrun
- Department of Materials and
Interfaces Weizmann Institute of Science, Rehovot 76100, Israel
| | - Shirley S. Daube
- Department of Materials and
Interfaces Weizmann Institute of Science, Rehovot 76100, Israel
| | - Roy H. Bar-Ziv
- Department of Materials and
Interfaces Weizmann Institute of Science, Rehovot 76100, Israel
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Bracha D, Bar-Ziv RH. Dendritic and Nanowire Assemblies of Condensed DNA Polymer Brushes. J Am Chem Soc 2014; 136:4945-53. [DOI: 10.1021/ja410960w] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Dan Bracha
- Department
of Materials and
Interfaces, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Roy H. Bar-Ziv
- Department
of Materials and
Interfaces, The Weizmann Institute of Science, Rehovot 76100, Israel
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Daube SS, Bar-Ziv RH. Protein nanomachines assembly modes: cell-free expression and biochip perspectives. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2013; 5:613-28. [DOI: 10.1002/wnan.1234] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 06/24/2013] [Accepted: 06/26/2013] [Indexed: 12/19/2022]
Affiliation(s)
- Shirley S. Daube
- Materials and Interfaces; Weizmann Institute of Science; Rehovot Israel
| | - Roy H. Bar-Ziv
- Materials and Interfaces; Weizmann Institute of Science; Rehovot Israel
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Abstract
Cell-free gene expression in localized DNA brushes on a biochip has been shown to depend on gene density and orientation, suggesting that brushes form compartments with partitioned conditions. At high density, the interplay of DNA entropic elasticity, electrostatics, and excluded volume interactions leads to collective conformations that affect the function of DNA-associated proteins. Hence, measuring the collective interactions in dense DNA, free of proteins, is essential for understanding crowded cellular environments and for the design of cell-free synthetic biochips. Here, we assembled dense DNA polymer brushes on a biochip along a density gradient and directly measured the collective extension of DNA using evanescent fluorescence. DNA of 1 kbp in a brush undergoes major conformational changes, from a relaxed random coil to a stretched configuration, following a universal function of density to ionic strength ratio with scaling exponent of 1/3. DNA extends because of the swelling force induced by the osmotic pressure of ions, which are trapped in the brush to maintain local charge neutrality, in competition with the restoring force of DNA entropic elasticity. The measurements reveal in DNA crossover between regimes of osmotic, salted, mushroom, and quasineutral brush. It is surprising to note that, at physiological ionic strength, DNA density does not induce collective stretch despite significant chain overlap, which implies that excluded volume interactions in DNA are weak.
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