New insights into the safety assessment of quantum dots: potential release pathways, environmental transformations, and health risks† Qing Liu,a Xiaomeng Ding,a Yanting Pang,a Yuna Cao,a Jialin Lei,a Jiawei Wua and Ting Zhang *a Abstract Quantum dots (QDs), also known as “artificial atoms”, are a new class of engineering nanoparticles. They are semiconductor nanocrystals composed of a few atoms and have good optical, electrical, electrochemical, and catalytic properties.