Special Issue "Molecular Self-Assembly 2011"

Guest Editor
Prof. Dr. Jurriaan Huskens
Molecular Nanofabrication Group, MESA+ Institute for Nanotechnology, University of Twente, TNW/MNF, PO Box 217, 7500AE Enschede, The Netherlands
Website: http://mnf.tnw.utwente.nl/
E-Mail:
Phone: +31 53 4892995
Fax: +31 53 4894645
Interests: host-guest chemistry; cyclodextrins; multivalency; supramolecular surface chemistry; supramolecular materials; nanolithography; soft lithography

Dear Colleagues,

Self-assembly provides a unique paradigm to obtain complex and functional molecular architectures in a spontaneous process from small building blocks. These building blocks are designed and preprogrammed with information which ensures the proper thermodynamic and structural properties of the resulting assembly. Essential features are therefore the tuning of inter- (and sometimes intra-) molecular interactions, the collective behavior of multiple interactions (multivalency, cooperativity), reversibility (potentially triggered by external stimuli) which allows error correction, and the expression of a function of the final assembly.

Self-assembly at surfaces can be particularly rewarding since the inherent immobilization and positioning allow characterization by surface analytical, amongst others single molecule, techniques and potential embedding in a device structure. Surfaces and interfaces play an ever larger role in supramolecular chemistry as this establishes the eminent position of supramolecular chemistry as a key enabler in nanotechnology.

The 2011 issue on molecular self-assembly invites the submission of papers on molecular self-assembly in the widest possible sense, ranging from solution systems to the assembly on surfaces and the application-oriented use of assembly in nanotechnology.

Prof. Dr. Jurriaan Huskens
Guest Editor

Related Special Issues

Molecular Self-Assembly in IJMS

Submission

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• self-assembly
• supramolecular chemistry
• nanotechnology
• interfacial assembly
• cooperativity
• multivalency
• dynamics

Type of Paper: Article
Title: Syntheses and Self-Assembling Behaviors of Pentagonal Conjugates of Tryptophane Zipper-Forming Peptides
Authors: Kazunori Matsuura, Kazuya Murasato and Nobuo Kimizuka
Affiliation: Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Japan;
E-Mail: ma2ra-k@mail.cstm.kyushu-u.ac.jp (K.M.)
Abstract: Pentagonal conjugates of tryptophane zipper-forming peptides (CKTWTWTE) with a pentaazacyclopentadecane core (Pentagonal-Gly-Trpzip and Pentagonal-Ala-Trpzip) were synthesized and their self-assembling behaviors were investigated in water. Pentagonal-Gly-Trpzip self-assembled into nanofibers with the width of about 5 nm in neutral water (pH 7) via formation of formation of tryptophane zipper, which irreversibly converted to nanoribbon by heat process. In contrast, Pentagonal-Ala-Trpzip formed irregular aggregates in water.

Type of Paper: Article
Title: pH Dependent Molecular Self-assembly of the Octaphosphonate Porphyrin of Nanoscale Dimensions: Spherical and Tubular Aggregation
Authors: Sheshanath V. Bhosale ¹, Mohan B. Kalyankar ^1,2, Santosh V. Nalage ², Cecilia H. Lalander ¹, Sidhanath V. Bhosale ², Steven J. Langford ¹
and Ruth F. Oliver ²
Affiliations: ¹ School of Chemistry, Monash University, Wellington road, Clayton Victoria-3800, Australia; E-Mail: sheshanath.bhosale@monash.edu (S.V.B.)
² Department of Organic Chemistry, North Maharashtra University, Jalgaon-425 001, India; E-Mail: sidhanath2003@yahoo.co.in (S.V.B.)
Abstract: Self-assembly of tetraphenylporphyrin with octaphosphonate (OctPor) side chains is statistical orientation with respect to the plane porphyrin showed spherical particles with diameters ranging from 70-80 nm at pH 5-7 in water, furthermore these particles self-organized and form nanorods at pH 8.5. Self-assembly only occurs in pH 5-9 was confirmed by fluorescence spectroscopy, as in pH range 3-5, the emission of OctPor was diminished, which may be due to the protonation of phosphonate end groups and the two nitrogen atoms of the core, AFM gives clear evidence for formation or larger aggregates than spherical and tubular aggregates. Nanostructes were characterized by UV/vis absorbance, fluorescence AFM and TEM microscopy. This interesting pH dependent self-assembly phenomenon could provide basis for development of novel biomaterials.

Type of Paper: Review
Title: Self-Assembly of Guanosine Derivatives in Solution
Authors: Irena Drevensek-Olenik, Lea Spindler, P. Mariani and G.P. Spada
Affiliation: Department for Complex Matter, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia; E-Mail: irena.drevensek@ijs.si (I.D.-O.)
Abstract: Guanosine derivatives show a remarkable ability to self-assemble into highly complex structures. The basic aggregation unit is the G-quartet, a hydrogen bonded array of four guanosine molecules, which is formed by a variety of guanosine derivatives and also in G-rich DNA and RNA sequences. Stacking of G-quartets leads to the formation of helical structures known as G-quadruplexes. The extent of stacking, and consequently the length of these supramolecular structures, is very sensitive to external parameters such as temperature, pH of solution, and added ions. Other self-assembling motifs, like G-ribbons, were also identified in solutions of lipophilic guanosine derivatives. Switching between G-ribbon and G-quadruplex structures was observed as a function of the solvent and cations in the solution. During the last years many research efforts focused on investigating the details of these self-assembly processes, from atomic scale conformation of the quadruplex, over dimer and G-quartet assembly, to guanosine based quadruplexes with lenths up to 50 nm. These recent results and discoveries will be reviewed in the paper.

Type of Paper: Review
Title: Self-Assembly on Gold Surfaces of Membrane Protein Scaffolds Engineered for Improved Monoclonal Immunoglobulin G Binding
Authors: Anton P. Le Brun ^1,#, Deepan S. H. Shah ², Dale Athey ², Stephen A. Holt ³ and Jeremy H. Lakey ¹
Affiliations: ¹ Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK; E-Mail: j.h.lakey@ncl.ac.uk
² Orla Protein Technologies Ltd, Biosciences Centre, International Centre for Life, Times Square, Newcastle upon Tyne, NE1 4EP, UK
³ Bragg Institute, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
^# Current address: Bragg Institute, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia;
E-Mail: abn@ansto.gov.au (A.P.L.B.)
Abstract: Bacterial outer membrane proteins, along with a filling lipid molecule can be modified to form stable self-assembled monolayers on gold [Terrettaz et al (2002) Protein Sci. 11, 1917-1925]. The transmembrane section of Escherichia coli outer membrane protein A has been engineered to create a scaffold protein to which functional motifs can be fused to it. We have fused the Z domain of Staphylococcus aureus protein A to the scaffold protein to create an antibody-binding array and its structure and assembly has been described [Le Brun et al (2011) Biomaterials in press]. Whilst the binding of rabbit polyclonal immunoglobulin G to the array is very strong, mouse monoclonal immunoglobulin G dissociates from the array easily. This is a problem in the creation of miniaturised diagnostic devices as monoclonal immunoglobulins are used due to their specificity for a single epitope. Here we describe a strategy to develop an antibody-binding array that will bind mouse monoclonal immunoglobulin G to the array with lowered dissociation rates. Fused to the scaffold protein are two double Z domains linked by polypeptide spacer thus allowing both Z domain binding sites of the immunoglobulin to be bound simultaneously. The new protein was expressed in Escherichia coli as inclusion bodies and was purified. The comparatively large array protein was refolded into a functional structure. Using surface plasmon resonance the self-assembly of the new protein on gold is shown and the improved binding of mouse monoclonal IgG is demonstrated.

Type of Paper: Article
Title: Enhanced Chiral Recognition by β-Cyclodextrin Dimers
Authors: Jens Voskuhl and Bart Jan Ravoo
Affiliation: Organic Chemistry Institute and CeNTech, Westfälische Wilhelms Universität Münster, Corrensstraße 40, 48149 Münster, Germany;
E-Mail: b.j.ravoo@uni-muenster.de (B.J.R.)
Abstract: In this paper we investigate the effect of multivalency in chiral recognition. To this end, we measured the host-guest interaction of a β-cyclodextrin dimer with divalent chiral guests. We describe the synthesis of carbohydrate-based water soluble chiral guests functionalized with two borneol, menthol, or isopinocampheol units in either (+) or (-)-configuration. We determined the chiral recognition of these divalent guests by a β-cyclodextrin dimer using isothermal titration calorimetry (ITC). It was found that – in comparison to β-cyclodextrin - the cyclodextrin dimer binds to guest dimers with an increased enantioselectivity, which clearly reflects the effect of multivalency.

Type of Paper: Article
Title: Controlled Placement of Sexithiophene Molecules on Silicon Oxide Templates
Authors: Cristiano Albonetti, Fabiola Liscio, Silvia Milita, Massimiliano Cavallini, Jean Francoise Moulin and Fabio Biscarini
Affiliation: Istituto per lo Studio dei Materiali Nanostrutturati, Consiglio Nazionale delle Ricerche, Sezione di Bologna, Via P. Gobetti 101, I-40129 Bologna, Italy; E-Mails: c.albonetti@bo.ismn.cnr.it (C.A.); f.biscarini@bo.ismn.cnr.it (F.B.)
Abstract: Nanoscale fabrication of ordered monolayer films of conjugated organic molecules is presented. The process makes it possible to grow sexithiophene monolayers (T6) at precise locations on a silicon substrate with a high degree of order. The process is based on the integration of parallel local anodic oxidation of the substrate and template growth of the molecular thin film. The former is used to fabricate silicon oxide arrays of parallel lines (400 nm in width) and grids on large area (1cm^2). The monolayer film of organic molecules is conformal to the features of the fabricated motives. This effect has been investigated by Atomic Force Microscopy and in situ X-ray diffraction.