Not only is our body made of individual organs, our cells themselves are made of tiny organelles, a variety of separate compartments that fulfill different tasks. Such functional, nanostructured systems would also be useful for technical applications, such as biosensors, self-repairing materials, optoelectronic components, or nanocapsules.
However, it has not been possible to recreate structures with sufficient complexity in the lab. Researchers in the Netherlands, led by Jan van Esch at the Universities of Delft and Groningen as well as the BioMaDe Technology Foundation, are now pursuing a new angle. As they report in the journal Angewandte Chemie, they allow surfactants and gelators to form aggregates. These aggregates coexist without interfering with each other and thus make versatile, highly complex structures with separate compartments.
Cells contain various components, such as channels, “motors”, structural frameworks (cytoskeleton), and “power plants” (mitochondria). In order for these to form, their building blocks, mainly proteins and lipids, must “recognize” each other and form the correct assembly by self-aggregation. In addition, it is critical that compatible components do not separate into different phases: when proteins fold, the water-loving (hydrophilic) and water-repellent (hydrophobic) parts of the molecule stay far away from each other and aggregate with “like-minded” components. Biomembranes are formed when many small lipid molecules aggregate such that their hydrophobic “tails” face inward together and their hydrophilic “heads” point outward toward the aqueous medium.
The Dutch team imitated this concept by using two types of self-aggregating compounds: surfactants and gelators. Like the lipids in natural membranes, surfactants have a hydrophilic segment and a hydrophobic segment and aggregate into structures such as membrane-like double layers or vesicles (bubbles). To imitate the forces involved in protein folding—hydrogen-bridge bonds and hydrophobic interactions—the team used a disk-shaped gelator, in which hydrophobic and hydrophilic molecular components alternate in concentric rings. Just as for proteins, like attracts like. This causes the disks to stack together into columns, which forms long fibers, generating a three-dimensional network in the solution to make a gel.
The researchers allow their surfactants and gelators to aggregate together. In this process, the different components take no notice of each other. This independent formation of different supramolecular structures within a single system is called orthogonal self-aggregation. This results in the formation of novel, complex, compartmentalized architectures, for example, interpenetrating but independent networks or vesicle configurations that coexist with gel fibers.
Author: Jan van Esch, University of Delft (The Netherlands), http://www.tudelft.nl/live/pagina.jsp?id=32e323ab-be78-43e4-96db-e6452fc418e5&lang=en
Title: Preparation of Nanostructures by Orthogonal Self-Assembly of Hydrogelators and Surfactants
Angewandte Chemie International Edition 2008, 47, No. 11, 2063–2066, doi: 10.1002/anie.200704609
Jan van Esch | Angewandte Chemie
A Varied Menu
25.03.2019 | Albert-Ludwigs-Universität Freiburg im Breisgau
Key evidence associating hydrophobicity with effective acid catalysis
25.03.2019 | Tokyo Metropolitan University
DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.
The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...
Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.
The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...
Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.
Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...
The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.
A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...
Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.
"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...
11.03.2019 | Event News
01.03.2019 | Event News
28.02.2019 | Event News
25.03.2019 | Trade Fair News
25.03.2019 | Life Sciences
25.03.2019 | Information Technology