OLED catheters for inner-body phototherapy: A case of type 2 diabetes mellitus improved via duodenal photobiomodulation.

Phototherapeutics has shown promise in treating various diseases without surgical or drug interventions. However, it is challenging to use it in inner-body applications due to the limited light penetration depth through the skin. Therefore, we propose an organic light-emitting diode (OLED) catheter as an effective photobiomodulation (PBM) platform useful for tubular organs such as duodenums. A fully encapsulated highly flexible OLED is mounted over a round columnar structure, producing axially uniform illumination without local hotspots. The biocompatible and airtight OLED catheter can operate in aqueous environments for extended periods, meeting the essential requirements for inner-body medical applications. In a diabetic Goto-Kakizaki (GK) rat model, the red OLED catheter delivering 798 mJ of energy is shown to reduce hyperglycemia and insulin resistance compared to the sham group. Results are further supported by the subdued liver fibrosis, illustrating the immense potential of the OLED-catheter-based internal PBM for the treatment of type 2 diabetes and other diseases yet to be identified.

The effect of proto-type wearable light-emitting devices on serum 25-hydroxyvitamin D levels in healthy adults: a 4-week randomized controlled trial.

BACKGROUND: Many people in modern society have insufficient exposure to ultraviolet B (UVB) sunlight, which may lead to vitamin D deficiency. We aimed to investigate the effect of a proto-type wearable light-emitting diode (LED) device emitting UVB light on serum 25-hydroxyvitamin D levels. METHODS: A total of 136 healthy adults were randomly assigned to receive either an active device emitting UVB light with a peak wavelength of 285 nm (n = 64) or a sham device emitting visible light (n = 72). All participants wore the device for a total of two minutes, one minute on each forearm, every day for 4 weeks. Serum 25-hydroxyvitamin D levels were assessed at baseline, 2, and 4 weeks of intervention, and 2 weeks after the end of the intervention. RESULTS: A significant difference was found between the experimental and control groups in changes in serum 25-hydroxyvitamin D levels from baseline after two (0.25 ± 3.10 ng/mL vs. -1.07 ± 2.68 ng/mL, p = 0.009) and 4 weeks of intervention (0.75 ± 3.98 ng/mL vs. -1.75 ± 3.04 ng/mL, p < 0.001). In the experimental group, the dropout rate due to mild, self-limiting adverse skin reactions was 11.8% (9/76). The mean total 25-hydroxyvitamin D production after UVB exposure was estimated at 0.031 ng/mL per 1 cm2 of skin area. CONCLUSIONS: A prototype wearable LED UVB device was effective for improving 25-hydroxyvitamin D status. The development of a safer wearable LED device for phototherapy may provide a novel daily, at-home option for vitamin D supplementation.