Tiny, biocompatible, self-powered nanogenerators could soon offer a wearable solution to boost healing through electrotherapy. Natural wound healing involves molecular interactions triggered by the weak electrical charge present in some types of biological tissue. 

External electric currents have been used to speed up the natural healing process since the mid-1900s. Seeking to replace the bulky electrodes used in older electrotherapy procedures, current research has focused on developing flexible, lightweight piezoelectric and triboelectric nanogenerators, such as this biodegradable triboelectric bone implant.

In January, scientists at the National Tsing Hua University in Taiwan published a paper that provides a broad overview of current designs and medical applications of self-powered piezoelectric and triboelectric nanogenerators. This review, published in the journal Science and Technology of Advanced Materials, offers insight into current challenges, potential applications, and the eventual commercialization of wearable nanotechnology for wound healing.

Piezoelectric materials generate an electric current under mechanical stress; this is the same process that creates a spark in a household propane grill lighter. The paper explores research into piezoelectric nanogenerators (PENGs) made of natural materials, including crystals, rubber, silk, wood, bone, and hair, as well as synthetic materials such as ceramics, polymers, and quartz analogs. The review determined that non-toxic, bendable synthetics offer the most promising results for accelerated tissue healing. A polyurethane/polyvinylidene fluoride (PU-PVDF) PENG implanted in rats accelerated wound fibrosis, a natural process involved in tissue remodeling.

Placing certain dissimilar materials together and then separating them will also produce an electric current, a process called “triboelectrification”. The review discusses triboelectric nanogenerators (TENGs) made of synthetic polymers. A wearable patch that combines TENGs with topical antibiotics to address infection can generate electricity from breathing movements. Rat studies show that the patch successfully accelerated wound healing in rats.

Further development is needed to address customized fitting and potential corrosion issues before PENGs and TENGs can reliably be used for wound healing. When biocompatible, self-powered nanogenerators do enter the market, they have great potential to provide cost-effective and efficient wound care.