Although we have heard that electrical stimulation can accelerate wound healing, the electronic devices themselves usually cannot be implanted in soft tissue, according to foreign media reports. However, thanks to the development of a new "piezoelectric chip", this situation may soon change. If the implant is too hard or rigid or made of toxic materials, the body's immune system will see it as a foreign object. As a result, it becomes covered with scar tissue and reduces its functionality.

Scientists from the University of Wisconsin, led by Professor Wang, have developed a patch-like tissue-stimulating implant that could solve this type of problem. The implant, called a piezoelectric wafer, contains crystals of the non-toxic amino acid lysine. Through a self-assembly process, these crystals are formed and arranged between two pieces of flexible, biocompatible, biodegradable polymer polyvinyl alcohol (PVA).

The crystals are known to be piezoelectric, so this means they generate an electrical charge when subjected to mechanical stress. When some of the crystal/PVA wafers were implanted in the chest and legs of rats, the researchers found that the animals' regular muscle movements were sufficient to produce a measurable electrical output. Conceivably, this electrical current could one day be used to stimulate biological tissue in adjacent injured human patients to aid in the healing process.

In addition, blood tests showed that when the wafers eventually dissolved in the rats, they had no harmful effects," Wang said. "We believe this technology opens up a huge range of possibilities, which include real-time sensing, accelerated healing of wounds and other types of injuries, and electrical stimulation for pain and other neurological disorders. Importantly, our rapid self-assembly technology dramatically reduces the cost of such devices, which has the potential to greatly expand the use of this very promising form of medical intervention." Wang has previously developed a frictional electrical patch that can be placed on fractured bones to help them heal, plus he has created an external bandage to stimulate wounds that is powered by the movement of the patient's chest as they breathe.