Table 1.

Examples of melanin-like NPs for bioimaging applications.

Melanin-Like NPs Type	Size (nm)	Model	Modality	Reference
MNPs	<10 nm	U87MG/HT29 tumor	PAI/PET/MRI	[28]
89Zr-MMPP	4.5 nm	AKI mice	MRI/PET	[29]
OMVMel	20–100 nm	4T1	PAI	[31]
Melanin-free acid	6.9 ± 1.2 nm	Breast cancer	PAI	[47]
PDA	48 ± 12 nm	mice	PAI	[50]
PDA	130 nm	B16 melanoma	PAI	[51]
MNPs	40 nm	Osteoarthritis	PAI	[52]
PDA-FONs	A broad scale	HIN-3T3 cells	FI	[56]
F-PDA	60 ± 10 nm	Hela cells	FI	[57]
PDA	~50 nm	A549 cells	FI	[58]
Fe3+-MelNPs	98/318/570 nm	mice	MRI	[67]
Fe3+,64Cu2+-MNPs	16.4 nm	HT29	PET/MRI/PAI	[68]
Mn2+-MNP	~5.6 nm	HeP-2 tumor	MRI	[69]
MnEMNPs	40–150 nm	U87MG	PAI/MRI	[70]
Gd3+,64Cu2+-MNPs	13 nm	Nude mice	MRI/PET/PAI	[71]
64Cu2+-MNPs	~60 nm	HepG2 tumor	PET/PAI	[72]
MNP-Ag-131I	12 nm	PC3 tumor	SPECT	[73]