Biomimetic Reflectors Fabricated Using Self-Organising, Self-Aligning Liquid Crystal Polymers

1. Ariosto Matranga, 
2. Sarwat Baig, 
3. Jessica Boland, 
4. Christopher Newton, 
5. Timothy Taphouse, 
6. Gary Wells, 
7. Stephen Kitson^*

Article first published online: 8 NOV 2012

DOI: 10.1002/adma.201203182

The photograph shows a polymer reflector that mimics the colour and underlying molecular structure of a golden beetle. It is formed from self-organizing layers of photopolymerised liquid crystal. These require an aligning layer, but we show that a layer of the material can be used as to self-align subsequent coatings, enabling the construction of complex structures by sequential coating of engineered materials.

Superoleophobic Surfaces: Hierarchically Structured Superoleophobic Surfaces with Ultralow Contact Angle Hysteresis

1. Arun K. Kota¹, 
2. Yongxin Li¹, 
3. Joseph M. Mabry², 
4. Anish Tuteja^1,*

Article first published online: 8 NOV 2012

DOI: 10.1002/adma.201290266

Hierarchically structured, superoleophobic surfaces are demonstrated that display one of the lowest contact angle hysteresis values ever reported – even with extremely low-surface-tension liquids such as n-heptane. Consequently, these surfaces allow, for the first time, even ≈2 μL n-heptane droplets to bounce and roll-off at tilt angles. ≤ 2°.

High-Throughput Profiling of Peptide–RNA Interactions Using Peptide Microarrays

Jaeyoung Pai †, Taejin Yoon †, Nam Doo Kim ‡, Im-Soon Lee §, Jaehoon Yu *, and Injae Shin *†

^† National Creative Research Center for Biofunctional Molecules, Department of Chemistry, Yonsei University, Seoul 120-749, Korea

^‡ New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu 706-010, Korea

^§ Department of Biological Sciences, Konkuk University, Seoul 143-701, Korea

 Department of Chemistry and Education, Seoul National University, Seoul 151-742, Korea

J. Am. Chem. Soc., Article ASAP

DOI: 10.1021/ja309760g

Publication Date (Web): October 30, 2012

Copyright © 2012 American Chemical Society

A rapid and quantitative method to evaluate binding properties of hairpin RNAs to peptides using peptide microarrays has been developed. The microarray technology was shown to be a powerful tool for high-throughput analysis of RNA–peptide interactions by its application to profiling interactions between 111 peptides and six hairpin RNAs. The peptide microarrays were also employed to measure hundreds of dissociation constants (K_d) of RNA–peptide complexes. Our results reveal that both hydrophobic and hydrophilic faces of amphiphilic peptides are likely involved in interactions with RNAs. Furthermore, these results also show that most of the tested peptides bind hairpin RNAs with submicromolar K_d values. One of the peptides identified by using this method was found to have good inhibitory activity against TAR–Tat interactions in cells. Because of their great applicability to evaluation of nearly all types of RNA–peptide interactions, peptide microarrays are expected to serve as robust tools for rapid assessment of peptide–RNA interactions and development of peptide ligands against RNA targets.

Programmable Sub-nanometer Sculpting of Graphene with Electron Beams

Felix Börrnert †, Lei Fu ‡, Sandeep Gorantla †, Martin Knupfer †, Bernd Büchner †, and Mark H. Rümmeli *§

^† IFW Dresden, PF 27 01 16, 01171 Dresden, Germany

^‡ College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072, China

^§ Technische Universität Dresden, 01062 Dresden, Germany

ACS Nano, Article ASAP

DOI: 10.1021/nn304256a

Publication Date (Web): October 30, 2012

Copyright © 2012 American Chemical Society

Electron beams in transmission electron microscopes are very attractive to engineer and pattern graphene toward all-carbon device fabrication. The use of condensed beams typically used for sequential raster imaging is particularly exciting since they potentially provide high degrees of precision. However, technical difficulties, such as the formation of electron beam induced deposits on sample surfaces, have hindered the development of this technique. We demonstrate how one can successfully use a condensed electron beam, either with or without C_s correction, to structure graphene with sub-nanometer precision in a programmable manner. We further demonstrate the potential of the developed technique by combining it with an established route to engineer graphene nanoribbons to single-atom carbon chains.

Landing and Catalytic Characterization of Individual Nanoparticles on Electrode Surfaces

Steven E. F. Kleijn †, Stanley C. S. Lai ‡, Thomas S. Miller ‡, Alexei I. Yanson †, Marc T. M. Koper *†, andPatrick R. Unwin *‡

^† Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands

^‡ Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom

J. Am. Chem. Soc., Article ASAP

DOI: 10.1021/ja309220m

Publication Date (Web): October 26, 2012

Copyright © 2012 American Chemical Society

We demonstrate a novel and versatile pipet-based approach to study the landing of individual nanoparticles (NPs) on various electrode materials without any need for encapsulation or fabrication of complex substrate electrode structures, providing great flexibility with respect to electrode materials. Because of the small electrode area defined by the pipet dimensions, the background current is low, allowing for the detection of minute current signals with good time resolution. This approach was used to characterize the potential-dependent activity of Au NPs and to measure the catalytic activity of a single NP on a TEM grid, combining electrochemical and physical characterization at the single NP level for the first time. Such measurements open up the possibility of studying the relation between the size, structure and activity of catalyst particles unambiguously.

High-Performance Nanopapers Based on Benzenesulfonic Functionalized Graphenes

Wenyi Huang , Xilian Ouyang , and L. James Lee *

Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio 43210, United States

ACS Nano, Article ASAP

DOI: 10.1021/nn303917p

Publication Date (Web): October 25, 2012

Copyright © 2012 American Chemical Society

High-performance graphene nanopapers are prepared from an aqueous solution of functional graphenes with benzenesulfonic acid groups via covalent bonds. The formed hydrophobic graphene nanopapers showed the highest tensile strength of 360 MPa and Young’s modulus of 102 GPa for samples with 13.7 wt % functional group and annealed at 150 °C. These samples showed a high electrical conductivity of 4.45 × 10⁴ S/m after being annealed at 250 °C. The aforementioned properties of graphene nanopapers are much higher than any previously reported data. The properties of nanopapers depend on the degree of functionality on graphenes and the annealing temperatures, which are further evidenced by X-ray photoelectron spectroscopy, FTIR, and X-ray diffraction patterns. Such unique nanopapers can be easily bounded and sandwiched onto any solid surface to give rise to great potentials in many applications such as gas diffusion barriers, EMI shielding, thermal management, and anticorrosion.

Photo- and Thermoresponsive Polymersomes for Triggered Release†

1. Dr. Esther Amstad^1,‡, 
2. Prof. Dr. Shin-Hyun Kim^1,2,‡, 
3. Prof. Dr. David A. Weitz^1,*

Article first published online: 5 NOV 2012

DOI: 10.1002/anie.201206531

Microfluidics: Thermo- and photoresponsive polymersomes are assembled using capillary microfluidic devices. Encapsulants can be selectively released from the thermoresponsive polymersomes if they are incubated at and above temperatures of 40 °C, whereas the photoresponsive polymersomes selectively release encapsulants if illuminated with laser light (see picture; NP=nanoparticle).