Facile and cost-effective fabrication of wearable alpha-naphtholphthalein-based halochromic sensor for wound pH monitoring

Abstract

The sensor, designed to be worn directly on the skin, is suitable for real-time monitoring of the recovery level of not only general wounds, but also difficult-to-heal wounds, such as those with chronic inflammation. Notably, healthy skin has a pH range of 4–6. When a wound occurs, the pH is known to be approximately 7.4. In this study, alpha-naphtholphthalein (Naph) was immersed in a cotton-blended textile to produce a wearable halochromic sensor that clearly changed color depending on the pH of the skin in the range 6–9, including pH 7.4, which is the skin infection state. The coating was performed without using an organic solvent by dissolving it in micelle form using cetyltrimethylammonium bromide, a surfactant, in water. Naph-based halochromic sensor shows light yellow, which is the dye's own color, at pH 6, which is a healthy skin condition, and gradually showed a clear color change to light green-green-blue as pH increased. Even after washing and drying by rubbing with regular tap water, the color change due to pH was maintained more than 10 times. Naph-based halochromic sensors use a simple solution production and coating method and are not only reusable sensors that can be washed with water but also use environmentally friendly water, making them very suitable for developing commercial products for wound pH monitoring. In addition, it can be easily applied to medical supplies, such as medical gauze, patient clothes, and compression bandages, as well as everyday wear, such as clothing, gloves, and socks. Therefore, it is expected to be widely used as a wound pH sensor, allowing real-time monitoring of the skin condition of individuals with chronic skin inflammation, including patients requiring wound recovery.

Enhancing wound healing through deep reinforcement learning for optimal therapeutics

“…As discussed in Zlobina et al [9], the function f can be an unmanageable nonlinear function that defines different cell transitions during wound healing. The nonlinear state x associated with wound healing surveyed in the literature may include variables such as pH, temperature [32][33][34][35][36][37] or visual representations captured through images of the wound [38]. We assume that x can be measured by some sensor, but f is unknown to the control algorithm.…”