Upconversion nanoparticles possess unique optical properties, making them attractive for applications in bioimaging, sensing, and medical treatments. However, their potential toxicity remains a significant concern. This review aims to provide a thorough analysis of the toxicity linked with upconversion nanoparticles. It examines various aspects, in

Zinc oxide is a mineral renowned for its remarkable strength to protect delicate skin. This gentle element has long been employed in a number of skincare products, from sunscreens to diaper rash creams, due to its remarkable protective characteristics. Creating a physical barrier on the skin's surface, zinc oxide effectively absorbs harmful radia