Flexible and Scalable Dry Conductive Elastomeric Nanocomposites for Surface Stimulation Applications.

OBJECTIVE: The study describes the development and testing of a dry surface stimulation flexible electrode (herein referred to as Flexatrode), a low-cost, flexible, and scalable elastomeric nanocomposite using carbon black (CB) and polydimethylsiloxane (PDMS). METHODS: Flexatrodes composed of CB and PDMS were developed and tested for mechanical and functional stability up to 7 days. Uniform CB distribution was achieved by optimizing the dispersion process using toluene and methyl-terminated PDMS. Electromechanical testing in the through thickness directions over a long-term duration demonstrated stability of Flexatrode. Thermal stability of Flexatrode for up to a week was tested and validated, thus mitigating concerns of heat generation and deleterious skin reactions such as vasodilation or erythema. RESULTS: 25 wt.% CB was determined to be the optimal concentration. Electrical and thermal stability were demonstrated in the through thickness direction. CONCLUSION: Flexatrode provides stable electrical properties combined with high flexibility and elasticity. Electrotherapy treated chronic wounds were 81.9% smaller than baseline at day 10. Wounds that received an inactive device (device without any electrical stimulation) were 58.1% smaller than baseline and wounds that received standard of care treatment were 62.2% smaller than baseline. SIGNIFICANCE: The increasing need for wearable bioelectronics requiring long-term monitoring/treatment has highlighted the limitations of sustained use of gel-based electrodes. These can include skin irritation, bacterial overgrowth at the electrode site, gel dehydration over time, and signal degradation due to eccrine sweat formation. Flexatrode provides stable performance in a nanocomposite with scalable fabrication, thus providing a promising platform technology for wearable bioelectronics.

An Absorbent, Flexible, Transparent, and Scalable Substrate for Wound Dressings.

Objective: Wound dressings that create and maintain a moist environment provide the optimal conditions for wound healing by increasing the rate of epithelialization and angiogenesis. However, current wound dressings require periodic removal which exposes the wound to the surrounding environment, thereby increasing the likelihood for infection and drying out the wound itself. There remains an unmet medical need for the development of an absorbent, flexible, and transparent wound dressing that can conform to the irregular geometry of the wound for a long-term duration. Herein, we report the development of AFTIDerm, an Absorbent, Flexible, Transparent, and Inexpensive moisture-management wound dressing using Polyvinyl alcohol (PVA) as the host material. Methods:AFTIDerm substrates of varying glycerol concentrations (1 wt%, 3 wt%, 5 wt%, 7 wt%, and 10 wt%) were fabricated and tested. The mechanical, absorption, and biological properties of AFTIDerm were evaluated. Results: We found that 5% glycerol served as the optimal concentration for AFTIDerm. The biocompatibility, absorptive capabilities, and scalability render PVA/glycerol an ideal material composition for wound dressings. Benchtop experimentation and pre-clinical testing demonstrate AFTIDerm as a platform for use in wound dressings. Discussion/Conclusion: The development of AFTIDerm broadens the translational utility of this materials platform not only as a material for wound dressings to minimize dressing changes in low to moderate exudate environments, but also as a potential substrate material for smart bandages. Clinical and Translational Impact Statement- AFTI Derm, an absorbent, flexible, and transparent wound dressing, maintains the moist environment required for healing while enabling monitoring of healing without removal and disruption to the wound bed.