One of nature’s best strategies for movement at the cellular scale involves powerful molecular motors: complex molecules that transform chemical energy into mechanical energy to complete tasks such as transporting components within the cell, contracting muscle fibers and snipping apart strands of DNA.A newly designed molecular motor tackles both these challenges by switching between rotation and fluorescence when hit by different light wavelengths, according to a study published in Science Advances.Pshenichnikov and his colleagues, under the guidance of Groningen organic chemist and 2016 Nobel Prize winner Ben Feringa, created the double-function molecule by attaching a chemical called triphenylamine to a basic molecular motor.Additionally, unlike typical molecular motors driven by tissue-damaging ultraviolet light, this new compound responded to shades of infrared that can penetrate deeper under the skin without damage.Salma Kassem, a chemist at the City University of New York, who was not involved in the study, says the design is an important step toward light-driven pharmacology: “It’s challenging to combine self-reporting and functionality in one small molecule without the two properties interfering with each other."