Provided is a removable tattoo ink that is composed of colored micro-particles that create permanent tissue markings, such as tattoos. The micro-particles include an inner core housing a bio-absorbable chromophore and an outer shell, which includes polystyrene sulfonate and polyallylamine hydrochloride and is designed for rupture with ultrasonic energy. The micro-particles can be implanted in the tissue of a subject, for example to create a tattoo and ruptured in situ by the application of ultrasonic energy to remove the tattoo. Also provided are methods of making the colored micro-particles.
