New polymer surface switches between capture and release

Biomedicines are produced by living cells, and can be used to treat cancer and autoimmune diseases, among other things. One challenge with biomedicines is that they are very expensive to produce, something that limits global access.

Now, researchers from Chalmers University of Technology in Sweden have invented a material that uses electrical signals to capture and release biomolecules. This new and efficient method may have a major impact on the development of biomedicines, and could pave the way for the creation of electronic pills and drug implants.

The new material is a polymer surface, which, in response to an electrical pulse, can change state from capturing to releasing biomolecules. This material has several possible applications, including use as a tool for the efficient separation of a biomedicine from the other biomolecules that cells create during the biomedicine production process. The researchers report this work in a paper in Angewandte Chemie.

Biomedicines are very expensive to produce due to the lack of an efficient separation technique. New techniques with a higher drug yield are thus required to reduce production costs and ultimately the cost of treating patients.

“Our polymer surfaces offer a new way of separating proteins by using electrical signals to control how they are bound to and released from a surface, while not affecting the structure of the protein,” says Gustav Ferrand-Drake del Castillo, who publicly defended his doctoral thesis in chemistry at Chalmers and is the lead author of the paper.

The conventional separation technique – chromatography – binds biomolecules tightly to the surface of a material, and strong chemicals are then required to release them. But many new biomedicines have proved to be highly sensitive to strong chemicals, which leads to losses and a poor yield.

The new polymer surfaces permit lower consumption of chemicals, benefiting the environment, while the fact that the surfaces can also be reused through several cycles is a key property. The process can be repeated hundreds of times without affecting the surface.

The material also functions in biological fluids with a buffering capacity, meaning fluids with the ability to counteract changes in pH value. This property is remarkable since it paves the way for the creation of a new technique for implants and electronic ‘pills’ that release medicine into the body via electronic activation.

“You can imagine a doctor, or a computer program, measuring the need for a new dose of medicine in a patient, and a remote-controlled signal activating the release of the drug from the implant located in the very tissue or organ where it’s needed,” says Ferrand-Drake del Castillo.

Local, activated drug release is available today via materials that change their state in the event of a change in the surrounding chemical environment. For example, tablets made from a pH-sensitive material are produced for releasing a drug in the gastrointestinal tract, which is an environment with natural variations in pH value. But in most of the body’s tissues there are no changes in pH value or other chemical parameters.

“Being able to control the release and uptake of proteins in the body with minimal surgical interventions and without needle injections is, we believe, a unique and useful property,” says Ferrand-Drake del Castillo. “The development of electronic implants is only one of several conceivable applications that are many years into the future. Research that helps us to link electronics with biology at a molecular level is an important piece of the puzzle in such a direction.”

Another advantage of the new method is that it does not require large amounts of energy. The low power consumption is due to the polymer layer on the surface of the electrode being very thin, on the nanometer scale. This means that the surface reacts immediately to small electrochemical signals.

“Electronics in biological environments is often limited by the size of the battery and the moving mechanical parts,” explains Ferrand-Drake del Castillo. “Activation at a molecular level reduces both the energy requirement and the need for moving parts.”

The research behind the technique was conducted during the period when Ferrand-Drake del Castillo was a doctoral student in Chalmers professor Andreas Dahlin’s research team in the Division of Applied Surface Chemistry. The project involved polymer surfaces that change state between being neutral and charged depending on the pH value of the surrounding solution. The researchers then succeeded in creating a material that was strong enough to stay on the surface when subject to repeated electrical signals, while also being thin enough to actually change pH value as a result of the electrochemistry on the surface.

“Shortly afterwards we discovered that we could use the electrical signals to control the binding and release of proteins and biomolecules, and that the electrode material works in biological solutions such as serum and centrifuged blood,” says Dahlin. “We believe and hope that our discoveries may be of great benefit in the development of new medicines.”

This story is adapted from material from Chalmers University of Technology, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.