Polydopamine (PDA) is the end product of the dopamine monomer's self-oxidation polymerization process. PDA is gaining popularity in diagnostic and therapeutic purposes because of its unique properties like excellent biocompatibility, biodegradability, surface functionalization, adhesion, and photothermal, which can help in various biomedical applications. Many researchers have been working on polydopamine nanocomposites in recent years. PDA has been used to modify various structures, such as metal nanoparticles, in order to improve the nanosystem's stability and applicability. This review attempts to cover extremely recent works from 2018 to the present in light of recent developments in PDA nanocomposites. The development of novel PDA nanocomposites for therapeutic applications, such as PDA-metal, PDA-drug, PDA-photosensitizers, and PDA-biomolecules, has been covered in this review. The multiple biomedical applications highlighted in this review include the treatment of cancer, antimicrobial infections, and neurological disorders, as well as wound healing and biosensing. This review will not only help the new researcher to build their base but also for experts to extend their views in this field. © 2022 John Wiley & Sons Ltd.