New “smart” composite material for implants

Researchers of the Immanuel Kant Baltic Federal University, together with their colleagues, tested a new "smart" composite material based on a thermosensitive polymer poly-N-isopropylacrylamide (PNIPAM). The uniqueness of this polymer's properties lies in the ability to change significantly its physicochemical properties in the temperature range close to the human body temperature. The creation of composites on its basis, combined with magnetocaloric materials, will allow contactless magnetic field control of the properties of a temperature-sensitive polymer. The proposed concept will help in the development of new composite materials for bioactive "smart" implants, the properties of which can be controlled through a magnetic field, which will improve their functionality and establishment. Results of the research were published in the Materials Letters journal.

Functional materials are in great demand in various fields due to their ability to change properties under the influence of external factors: pressure, temperature, magnetic field etc. Their use in medicine is especially important: for example, when placing an implant made of artificial materials into the body, one often has to deal with inflammatory processes, long tissue encrustation, and so on. This can be cured by special substances that suppress undesirable effects and promote, for instance, the differentiation of local stem cells into a specific mature type. One of the effective solutions in this case is the drug implementation into the implant with its subsequent release into the body under the influence of either heat or other external factors (magnetic field, ultrasound, etc.)

This solution is consistent with the "delayed" treatment approach, which allows the required amount of the drug to be injected at the right time.

"In this work, we investigated material based on the thermosensitive polymer poly-N-isopropylacrylamide (PNIPAM). It is interesting in that the so-called critical solution temperature—a reversible transition from the gel-like hydrophilic state to the wrinkled hydrophobic one—is approximately 32°C," says one of the authors of the project Christina Gritsenko, Research Associate at the Research and Education Center "Smart Materials and Biomedical Applications"at the Baltic Federal Immanuel Kant University.

Scientists from the Immanuel Kant Baltic Federal University (Kaliningrad) together with colleagues from the Kh.I. Amirkhanov Institute of Physics of the Dagestan Federal Research Center of the Russian Academy of Sciences, Pavel Josef Shafarik University (Košice) and the Lomonosov Moscow State University (Moscow) developed the "smart" composite material based on the PNIPAM thermosensitive polymer and magnetocaloric material gadolinium, which serves as both a cooler and a heater. To test this idea, the authors assembled a setup that allows real-time monitoring of changes in the properties of the temperature-sensitive polymer by applying a magnetic field. The experiments have demonstrated the possibility for a reversible control of polymer properties by applying a magnetic field.

"Our idea of controlling the properties of the thermosensitive polymer using a magnetic field has worked. This can help to develop new technologies for medicine, thanks to which it would be possible to perform a non-invasively release of the drug implemented into the implant with a required dose, using a magnetic field created by a commercial MRI machine," added the research author Abdulkarim Amirov.

Provided by Immanuel Kant Baltic Federal University