Light

"Light has an increasing number of applications in biology and medicine – it can be used to stimulate cell growth, manipulate neural signals, and treat some cancers – but it doesn’t easily pass through tissue."https://news.stanford.edu/stories/2026/04/researchers-use-ultrasound-to-create-light-inside-the-body?utm_source=join1440&utm_medium=email&utm_placement=newsletter&user_id=66c4c92f5d78644b3ac5d5b4