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Topical administration of drugs in a timely manner according to the physiological need at the wound site can enhance the healing rate of chronic wounds. Herein, an electronic wound dressing that enables active topical drug delivery in response to electrically induced pH change is demonstrated for potential treatment of chronic wounds. In this platform, the pH of the dressing is controlled using an electrical field. This allows precise electrical control over the temporal profile of pH-mediated drug release. This engineered dressing is comprised of microfabricated electrodes serving as anode and cathode, a pH sensitive hydrogel, and controlled electronic circuitry. The anode is coated with a pH sensitive poly(ethylene glycol)-diacrylate/Laponite hydrogel layer containing drug loaded chitosan nanoparticles (ChPs). Applying a DC voltage between the electrodes results in a local change in pH near the electrodes. In basic environments found near the anode, the ChPs release their drug due to the dehydration process, while in acidic environments the release profile is negligible. Turning off the DC voltage results in immediate pH recovery and cessation of drug release. The biocompatibility of the dressing has also been confirmed-the pH shift resulting from application of DC voltage does not affect the wound pH significantly., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Current methods in treating chronic wounds have had limited success in large part due to the open loop nature of the treatment. We have created a localized 3D-printed smart wound dressing platform that will allow for real-time data acquisition of oxygen concentration, which is an important indicator of wound healing. This will serve as the first leg of a feedback loop for a fully optimized treatment mechanism tailored to the individual patient. A flexible oxygen sensor was designed and fabricated with high sensitivity and linear current output. With a series of off-the-shelf electronic components including a programmable-gain analog front-end, a microcontroller and wireless radio, an integrated electronic system with data readout and wireless transmission capabilities was assembled in a compact package. Using an elastomeric material, a bandage with exceptional flexibility and tensile strength was 3D-printed. The bandage contains cavities for both the oxygen sensor and the electronic systems, with contacts interfacing the two systems. Our integrated, flexible platform is the first step toward providing a self-operating, highly optimized remote therapy for chronic wounds.

Topical administration of drugs and growth factors in a controlled fashion can improve the healing process during skin disorders and chronic wounds. To achieve this goal, a dermal patch is engineered that utilizes thermoresponsive drug microcarriers encapsulated within a hydrogel layer attached to a flexible heater with integrated electronic heater control circuitry. The engineered patch conformally covers the wound area and enables controlled drug delivery by electronically adjusting the temperature of the hydrogel layer. The drugs are encapsulated inside microparticles in order to control their release rates. These monodisperse thermoresponsive microparticles containing active molecules are fabricated using a microfluidic device. The system is used to release two different active molecules with molecular weights similar to drugs and growth factors and their release profiles are characterized. This platform is a key step towards engineering smart and closed loop systems for topical applications.

Biodegradable nanofibrous polymeric substrates are used to fabricate suturable, elastic, and flexible electronics and sensors. The fibrous microstructure of the substrate makes it permeable to gas and liquid and facilitates the patterning process. As a proof-of-principle, temperature and strain sensors are fabricated on this elastic substrate and tested in vitro. The proposed system can be implemented in the field of bioresorbable electronics and the emerging area of smart wound dressings.