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Ionov L.,Leibniz Institute of Polymer Research
Materials Today | Year: 2014

The rapid development of microtechnology in recent times has increased the necessity for the development of devices, which are able to perform mechanical work on the micro- and macroscale. Among all kinds of actuators, the ones based on stimuli-responsive hydrogels, which are three-dimensional polymer networks strongly imbibed with water, deserve particular attention. This paper aims to provide a brief overview of stimuli-responsive hydrogel actuators with respect to their sensitivity to different stimuli, different kinds of deformation, the possibilities of generating different types of movement, as well as their applications. © 2014 Elsevier Ltd. All rights reserved.

Pompe T.,Leibniz Institute of Polymer Research
Nature protocols | Year: 2010

Surface- and matrix-bound signals modulate stem cell fate in vivo and in vitro. This protocol enables the immobilization of a wide range of biomolecules that contain primary amino groups to different types of solid carriers, including glass substrates and standard polystyrene well plates. We describe how thin polymer coatings of poly(octadecene-alt-maleic anhydride) can be used to covalently attach growth factors directly, or through poly(ethylene glycol) spacers, to solid supports at defined concentrations. Surface-immobilized growth factors can be presented over a wide range of concentrations (5-150 ng cm(-2)), as we have previously shown for leukemia inhibitory factor and stem cell factor. Cell activation can be achieved in the presence of adhesion-promoting extracellular matrix proteins. Depending on the methods used, the overall procedure takes 1.5-3 d. In general, the approach can be used to investigate the effect of defined amounts of immobilized growth factors on stem cells and on the maintenance, growth and differentiation of other cell types.

Ionov L.,Leibniz Institute of Polymer Research
Soft Matter | Year: 2011

Fabrication of 3D objects using folding of thin films is a novel and very attractive research field. The manuscript overviews recent advances in development and application of polymer films, which are able to fold and form 3D structures. © 2011 The Royal Society of Chemistry.

Ionov L.,Leibniz Institute of Polymer Research
Journal of Materials Chemistry | Year: 2010

This review addresses recent developments in actively moving materials based on stimuli-responsive polymers on the scale from single molecules to polymer networks. The examples of application of stimuli-responsive polymers for design of actuators, sensors, active elements in microfluidic devices, materials with switchable optical properties as well as biomaterials are discussed. Emphasis is given to biohybrid materials consisting of synthetic and living components as well as stimuli-responsive materials inspired by nature. © The Royal Society of Chemistry 2010.

Ionov L.,Leibniz Institute of Polymer Research
Advanced Functional Materials | Year: 2013

Active motion is intrinsic to all kinds of living organisms from unicellular ones to humans and inspires development of synthetic actively moving materials. Hydrogels, which are three dimensional polymer networks imbibed with aqueous solutions, mimic the swelling/shrinking behavior of plant cells and produce macroscopic actuation upon swelling and shrinking. This Feature Article covers basic principles of design as well as recent advances in the development of hydrogel based actuating systems. It is discussed how simply swelling can be used to generate very complex multistep motion, which can be used to develop new optical devices, sensors, biomaterials, smart surface, etc. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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