Table 1

Representative NIR fluorophores for ex vivo and in vivo labeling

Class	Name	Type	Targets	Labeling mechanism	Reference(s)
Small-molecule fluorophores	DiX series	Heptamethine cyanine	Cell membrane	Membrane insertion	14 50
	CIR38M	Heptamethine cyanine	Amine group on cell membrane protein	NHS ester amine reaction	55
	IRDye800CW	Heptamethine cyanine	Biomarker PD-L1	Antibody affinity	74
	ESNF13	Pentamethine cyanine	Mitochondria	Structure inherent targeting	2 19
	SH1	Heptamethine cyanine	Monocyte in bone marrow	Structure inherent targeting	20
	CTNF126	Heptamethine cyanine	Lysosome	Structure inherent targeting	52
	CDg16	Aminoacridine	Activated macrophage (M2)	Structure inherent targeting	78
	CDnir7	Heptamethine cyanine	Macrophage	Structure inherent targeting	76
Nanoparticles	Quantum dot	Semiconductor crystal	Biomarker protein	Antibody affinity	41
Nanoparticles	Rare-earth nanoparticle	Rare-earth atoms	Biomarker protein	Antibody affinity	79

NHS, N-hydroxysuccinimide; NIR, near-infrared; PD-L1, programmed cell death ligand-1.