Soft Matter Blog

Read the most popular Review Articles of 2011 for free today

Self-assembly of amphiphilic peptides
I. W. Hamley
Soft Matter, 2011, 7, 4122-4138
DOI: 10.1039/C0SM01218A

Stimulus responsive core-shell nanoparticles: synthesis and applications of polymer based aqueous systems
Olivier J. Cayre , Nelly Chagneux and Simon Biggs
Soft Matter, 2011, 7, 2211-2234
DOI: 10.1039/C0SM01072C

Cellulose nanowhiskers: promising materials for advanced applications
Stephen J. Eichhorn
Soft Matter, 2011, 7, 303-315
DOI: 10.1039/C0SM00142B

Polylactide (PLA)-based amphiphilic block copolymers: synthesis, self-assembly, and biomedical applications
Jung Kwon Oh
Soft Matter, 2011, 7, 5096-5108
DOI: 10.1039/C0SM01539C

Morphology of polymer-based bulk heterojunction films for organic photovoltaics
Matthias A. Ruderer and Peter Müller-Buschbaum
Soft Matter, 2011, 7, 5482-5493
DOI: 10.1039/C0SM01502D

Stimulus responsive nanogels for drug delivery
Liusheng Zha , Brittany Banik and Frank Alexis
Soft Matter, 2011, 7, 5908-5916
DOI: 10.1039/C0SM01307B

Covalently cross-linked amphiphilic block copolymer micelles
Cornelus F. van Nostrum
Soft Matter, 2011, 7, 3246-3259
DOI: 10.1039/C0SM00999G

PNIPAM microgels for biomedical applications: from dispersed particles to 3D assemblies
Ying Guan and Yongjun Zhang
Soft Matter, 2011, 7, 6375-6384
DOI: 10.1039/C0SM01541E

Nanoparticles with targeting, triggered release, and imaging functionality for cancer applications
Kristin Loomis , Kathleen McNeeley and Ravi V. Bellamkonda
Soft Matter, 2011, 7, 839-856
DOI: 10.1039/C0SM00534G

Hydrophilic and superhydrophilic surfaces and materials
Jaroslaw Drelich , Emil Chibowski , Dennis Desheng Meng and Konrad Terpilowski
Soft Matter, 2011, 7, 9804-9828
DOI: 10.1039/C1SM05849E

To keep up-to-date with all the latest research, sign up for the Soft Matter e-Alert or RSS feeds or follow Soft Matter on Twitter or Facebook.

Growing up is a stressful process, particularly during embryonic development. The embryo starts out as a single symmetric cell. This cell can be considered as an active fluid bound by the cell membrane. Flow within this fluid leads to the build-up of stresses, the formation of patterns and asymmetries within the cell. Stephan Grill, at the Max-Planck Insitute for the Physics of complex systems and the Max-Planck Institute for Molecular Cell Biology and Genetics, Dresden, is interested in understanding how these flows lead to the polarisation observed in the Caenorhabditis elegans zygote.

Grill has shown that the changes in cell polarity are driven by myosin flow on the surface of the cell. The cortex can be considered as a dynamic self-contracting polymer gel surface, which lies underneath the cell membrane. This polymer gel layer behaves as a thin film of an active fluid. Passive advective transport of molecules – in this case myosin – embedded in the fluid can occur depending on the diffusivity and the flow velocities of the molecules.  In C. elegans the flows are fast enough that advection does play a role, influencing the distribution of the molecules as they diffuse on the cortex. Modelling shows that the passive advective transport by flow of such a mechanically active materials acts as a trigger for the segregation of the proteins, resulting in the polarisation of the zygote.

The movement of myosin across the surface of the cell also results in anisotropies in the cortical tension. These so called active stresses cause isolated sections of the cortex to self-contract. Grill has developed a novel method for locally determining the stresses, by cutting the cortex with a laser and measuring the recoil. The cortical tension is found to be greatest in the direction orthogonal to the flow.

Grill suggests that advective transport in active fluids is a general mechanism for the formation of patterns in developmental biology.

For more information see:

Goehring, N.W. et al., Polarization of PAR Proteins by Advective Triggering of a Pattern-Forming System, Science, 2011.

Bois, S, et al., Pattern Formation in Active Fluids, Phys. Rev. Lett., 2011.

Mayer. M, et al., Anisotropies in cortical tension reveal the physical basis of polarizing cortical flows, Nature, 2010.

The image above is taken from: Cyclodextrin/dextran based drug carriers for a controlled release of hydrophobic drugs in zebrafish embryos, Soft Matter, 2011, and shows C. elegans embryo 30hrs after fertilisation.