October 25 - 11:00 pm
Room 217D - Edifício Departamental
EDUARDO MENDES
Advanced Soft Matter Group (ASM), Dept. Chem. Eng. Delft - University of Technology
Multi-responsive gel cilia: bulk, actuating properties and limits to miniaturization
Host: Mário Eusébio
Abstract
Polymer gels are privileged materials to interface the macroscopic world with living matter. These wet materials that allow for fluid flow in their bulk, can be easily made biocompatible and, therefore, envisaged as a support for living matter or body implants. Furthermore, due to their appropriate physico-chemical and mechanical properties they can be finely tuned either to mimic a biological function or to exert mechanical action on a living tissue. Their mechanical response can be driven by small perturbations of various natures and they are easy to deform when subject to small external mechanical or environmental changes. A wide range of actuating gel interfaces can be envisaged exhibiting various morphologies and trigged by different mechanisms of sensing or actuation. Within this framework, we report on large arrays of micro-fabricated gel cilia as a concrete example of a multi-responsive gel interface, that express sensing and motility (actuation) at the same time. First, we investigate in detail the magneto rheological response of highly swollen polymer gels that contain ferromagnetic particles under external homogeneous magnetic fields [1-2]. In a second moment, the microfabrication of a large array of gel cilia able to respond to pH changes and electric or magnetic fields is demonstrated [3-4]. The various limitations to miniaturization and response at (sub)micrometer length scales of such gel interfaces are also discussed. As a resume, we demonstrate how it is possible to integrate various types of stimuli into (potentially) biocompatible gels controlling gel morphology at micrometer scales.
References:
[1] H. An, S.. J. Picken and E. Mendes “Enhanced Hardening of Soft Self-Assembled Copolymer Gels Under Homogeneous Magnetic Fields” Soft Matter, 2010, 6, 4497
[2] H, An, B. Sun, S. J. Picken and E. Mendes “Long Time Response of Soft Magnetorheological Gels” J. Phys. Chem. 2012 116(15) 4702-11
[3] P.J. Glazer, M. van Erp, A. Embrechts, S.G. Lemay, E. Mendes “Role of pH gradients in the actuation of electro-responsive polyelectrolyte gels”, Soft Matter, 2012, 8 (16), 4421 – 4426
[4] P.J. Glazer, S. Lemay and E. Mendes, “Multi-stimuli responsive hydrogel cilia” Advanced Functional Materials, 23, 2013 2964
Short Bio:
Eduardo Mendes has a background in physics with MSc degree on theory of quantum systems interacting with light. He received a PhD degree in Physics from University of Strasbourg (France) working on the structure of polymer gels under deformation using small-angle neutron scattering. Immediately after his PhD thesis, he joined the École de Physique et de Chimie Industrielles de la Ville de Paris (Paris Tech) as a CNRS fellow, where he developed studies on polymer blends also using neutron scattering techniques.
Years later, still as a CNRS fellow, he moved back to Strasbourg to join the Laboratoire de Dynamique des Fluides Complexes a CNRS-University lab, where he concentrated most of his research efforts on the study of worm-like surfactant and copolymer assemblies, using rheology and scattering techniques.
In the late 90’s he obtained an Habilitation a Diriger des Recherches, also from University of Strasbourg, on copolymer self-assembling.
In the early 2000’s he spent a sabbatical year as a Visiting Professor at Delft University of Technology and some time later he was offered a position as Associate Professor in the Chemical Engineering Department. In 2014 he was a visiting Professor at Cornell University, at the department of Materials Science and Engineering.
His research on "Functional Soft Matter" is of fundamental nature and focus on the use of soft matter as unique systems that are able to exert "active or passive" functions such as transporting hydrogen atoms through a fuel cell membrane (passive) or a soft gel that deforms strongly in the presence of an electric or magnetic fields (active).
In recent years, his interest in health related problems as well as actuation in confined geometries has increased considerably and he has been carrying out research on the interface of Soft Matter and living cells such as gel actuation for cardio-vascular applications, nano carriers for drug delivery, imaging and alpha-therapy, or soft responsive gels in interaction with living cells.