(Nanowerk News) Wearable medical devices, such as a soft exoskeleton providing support for stroke patients or a controlled drug delivery patch, must be made of materials that can adapt intelligently and independently to the movement of the wearer and to changing environmental conditions.
It is a type of autonomously transferable polymer material recently developed by materials scientists at the University of Stuttgart and pharmacists at the University of Tübingen, whose research findings have been reported in Advanced Material Technology (“Automatic Adaptation of Intelligent Moisture Programmed Hydrogel Patches for Adjustable Stiffness and Drug Release”).
The collaboration group, chaired by Prof. Sabine Ludwigs (Institute of Polymer Chemistry) and Prof. Holger Steeb (Institute of Mechanics, MIB) at the University of Stuttgart and Prof. Dominique Lunter (in the Pharmacy Department of the University of Tübingen Technology), have published a paper in which they demonstrate how smart polymeric materials can be produced, where the word “smart” refers to the fact that the properties of materials can adapt independently to the environmental conditions in which they are used.
The stiffness of the material in question can change by more than four orders of magnitude depending on humidity and temperature, and can undergo elastic changes even when subjected to large deformations, allowing the mechanical properties to adapt to individual applications.
Very high degree of adaptability
One of the paper’s authors, Sabine Ludwigs, calls this material an “Intelligent Rubber Material” and explains that: “This high degree of adaptability makes our polymer suitable for robots made of soft organic materials, such as those used in biomedical or on missions. search and rescue – the key word here is ‘soft robot’. This polymer is also very suitable for use in smart skin applications, such as exoskeleton made of soft, flexible fabrics.”
For both applications, the material must allow both fast and slow motion, meaning it must have adaptable viscoelastic properties. “That’s what the materials we’ve developed are capable of,” says Holger Steeb.
In addition, the material’s hydro adaptability and reversible water absorption capacity make it suitable for use as a patch for controlled drug release through the skin. The researchers specifically conducted experiments with the release of the painkiller diclofenac in skin models. “The main mechanism is the patch itself which controls the release of the active ingredient in response to varying wound moisture levels, i.e. depending on fluid seeping out of the wound,” says Dominique Lunter, a pharmacist. expert based in Tübingen, Germany.
The relevant research was carried out as part of the recently established cross-faculty Soft Functional Materials Laboratory (FSM Lab) at the University of Stuttgart’s Cluster of Excellence Data-integrated Simulation Science (EXC 2075, SimTech). It is the result of a highly successful collaboration between two research groups led by Sabine Ludwigs who specializes in polymer chemistry, and Holger Steeb, whose work focuses on the mechanics and functions of intelligent polymeric materials.
Vision: materials that respond to active triggers
Going forward, researchers at the University of Stuttgart plan to investigate multifunctional material systems, which are able to adapt independently to their environment and react to active triggers, such as electrical stimuli. They also plan to use simulation as a basis for modeling and predicting complex architectures. Thus, the research results of polymeric materials are also of benefit to studies carried out by the university’s “Data-Integrated Simulation Science” (SimTech) excellence cluster.