In vivo multimodal multicolor nanotheranostic platform integrating magnetic enrichment, PA detection, PT therapy and real-time PA monitoring of PT therapeutic efficacy of circulating pathological cells, including circulating tumor cells (CTCs), circulating endothelial cells (CECs), circulating cancer stem cells (CCSCs), circulating bacterial cells (CBCs), emboli, and other biomolecules (i.e., DNA, RNA, exosomes and microparticles, etc.).