Methods of treatment of tissue with electromagnetic radiation (EMR) to produce lattices of EMR-treated islets in the tissue are disclosed. Specifically, methods of treating internal hard and soft tissues, such as but not limited to organs, bones, muscles, tendons, ligaments, vessels and nerves, with such EMR-treated islets are described. Also disclosed are devices and systems for producing lattices of EMR-treated islets in tissue, and cosmetic and medical applications of such devices and systems.