Biophotonics is that the study of optical processes in biological systems, both people who occur naturally and in bioengineered materials. A particularly important aspect of this field is imaging and sensing cells and tissue. This includes injecting fluorescent markers into a biological system to trace cell dynamics and drug delivery. The term biophotonics denotes a mixture of biology and photonics, with photonics being the science and technology of generation, manipulation, and detection of photons, quantum units of light. Photonics is related to electronics and photons.