Modern tattoos are rapidly transforming from pure art into functional tools, blurring the lines between the human body and the digital world. If body art once served as a means of self-expression or a tribute to traditions, today we are witnessing the birth of a new era – the era of “smart” biometric tattoos capable of saving lives and replacing complex medical devices. These high-tech solutions turn the skin into an interactive interface that is always at hand, yet completely imperceptible in everyday life.