Combining wireless stimulation and biosensors, smart bandage promotes seamless wound repair

Wireless smart bandage on human arm. Image source: Stanford University

Researchers at Stanford University in the United States published a paper in Nature Biotechnology on the 24th saying that they have developed a wireless smart bandage that accelerates the repair of injured tissue by monitoring the wound healing process and treating the wound. The researchers said that this bandage can promote faster wound closure, increase new blood flow to injured tissue, and promote skin recovery by significantly reducing scar formation.

The smart bandage consists of wireless circuits that use impedance/temperature sensors to monitor the progress of wound healing. If the wound is healing slowly or an infection is detected, the sensor notifies the central processing unit to apply more electrical stimulation to the wound to speed up tissue closure and reduce infection. The researchers were able to track the sensor data wirelessly in real time on a smartphone.

The bandage's electronics layer, which includes a microcontroller unit, radio antenna, memory, electrical stimulator, biosensors and other components, is just 100 micrometers thick, about the thickness of a layer of latex paint.

All of these circuits are mounted on a cleverly designed hydrogel that is integrated to deliver therapeutic electrical stimulation to injured tissue and collect real-time biosensing data.

The polymers in the hydrogel are engineered to adhere firmly to the wound surface when needed, but to pull away cleanly and gently without harming the wound when heated to just a few degrees above body temperature.

Electrical stimulation accelerates the migration of keratinocytes to the wound site, limiting bacterial infection and preventing biofilm formation on the wound surface, thereby actively promoting tissue growth and aiding tissue repair. The researchers took a well-studied technology and integrated it with real-time biosensor data to provide a new automated treatment modality informed by biosensors.

The biosensing capabilities of the smart bandage monitor biophysical changes in the local environment, providing a real-time, rapid, robust, and extremely accurate method to measure wound conditions.

The researchers will next investigate why and how electrical stimulation heals wounds faster. They believe that electrical stimulation promotes the activation of pro-regeneration genes, such as anti-inflammatory genes that aid in pathogen clearance and wound repair, and genes that increase muscle and soft tissue growth. Similarly, electrical stimulation increases the number of white blood cells by recruiting more M2 anti-inflammatory macrophages, which have important pro-regeneration effects.

We may not feel the benefits of a smart bandage if we have a small cut on our finger, but for serious wounds, ordinary bandages are obviously insufficient. The most critical point is that you cannot check the healing of the wound in real time. The longer the recovery period required for the wound, the more inconvenient it is, because in order to check the healing condition, medical staff can only remove the bandage frequently, and this operation will cause secondary damage to the fragile tissue. Technically speaking, smart bandages can well sense the changes in the conductivity and temperature of the skin during wound healing. The electrical impedance increases as the wound heals, and the local temperature decreases as the inflammation subsides. It not only promotes healing and prevents infection, but also can cope with different types of trauma.