Printed graphene circuit could control stem cell differentiation

American engineers have used electricity applied across a printed graphene circuit to encourage stem cells to differentiate into other cells which protect nerves. Their method could have applications in nerve regeneration research and therapies.

Nerve damage is excruciatingly painful, debilitating and often irreparable. While more and more researchers have been studying the regeneration of nervous tissue and hoping for a breakthrough, they are limited by a scarcity of resources.

Schwann cells – a type of cell which forms protective sheaths around nerve cells and promotes their health – are precious resources for researchers, but hard to come by in useful numbers.

Currently, Schwann cells are produced using a standard chemical process to differentiate bone marrow stem cells into Schwann cells. While bone marrow cells are readily available, the chemical process is lengthy, difficult and costly, requiring expensive growth factors.

A conversation on campus at Iowa State University between chemical engineers working on nerve regeneration and nanoengineers working on printed graphene technologies identified a possible new approach to the problem: using printed graphene circuits to harvest Schwann cells.

The team of nanoengineers – led by Jonathan Claussen, an assistant professor at the university – had developed a method for creating highly conductive graphene circuits. This uses a laser to effectively ‘stitch together’ the graphene flakes within the printed circuit. The treatment reduces the graphene oxide to graphene and improves electrical conductivity of the graphene more than a thousand times.

After treatment, the circuit’s rough, raised surface proved an ideal surface for bone marrow stem cells to adhere to and grown on. By adding small, regular doses of electricity – 100mV for 10 minutes every day over 15 days – the stem cells differentiated into Schwann-like cells.

Using the treated graphene circuit, the researchers found that 85 per cent of the stem cells differentiated into Schwann-like cells, compared with 75 per cent by the standard chemical process. The new method also yielded more nerve growth factor.

The group’s findings were featured on the front cover of Advanced Healthcare Materials.

“This technology could lead to a better way to differentiate stem cells,” said Dr Metin Uz, one of the study’s first authors. “There is huge potential here.”

This method could do away with the arduous steps of chemical processing, eliminate the need for expensive growth factors, create a framework for nerve damage repairs, and potentially increase control over stem cell differentiation with precise electrical stimulation.

The authors report that their new method could lead to changes in how nerve injury is treated inside the body.

“These results help pave the way for in vivo peripheral nerve regeneration where the flexible graphene electrodes could conform to the injury site and provide intimate electrical stimulation for nerve cell regrowth,” they write.

New possibilities opened up by the success of this method could include technology to create dissolvable or absorbable nerve regeneration materials that could be surgically placed in a person’s body and safely left inside.

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