text: Dopamine is one of neurotransmitters in the body which helps cells send impulses. Polydopamine (PDA) is obtained through the self-aggregation of dopamine to form a melanin-like substance under mild alkaline conditions. PDA has strong NIR absorption, good photothermal stability, excellent biocompatibility and biodegradability, and high photothermal conversion efficiency. Furthermore, with π conjugated structure and different active groups, PDA can be easily combined with various materials to achieve multifunction, such as fluorescence imaging, MRI, CT, PA, targeted therapy etc. In view of this, PDA and its composite nanomaterials have a broad application prospect in the biomedical field.
  Dopamine-melanin colloidal nanospheres is an efficient near-infrared photothermal therapeutic agent for in vivo cancer therapy. PDA can also be modified on the surface of other PTAs, such as gold nanorods, carbon-based materials, to enhance the photothermal stability and efficiency in vivo. For example, PDA-modified spiky gold nanoparticles (SGNP@PDAs) have been investigated for chemo-photothermal therapy.