Table 6.

Gold nanoparticles (AuNPs) in photoacoustic (PA) imaging.

AuNP	In Vitro Effects	In Vivo Effects	Ref.
Nanorod 45 nm × 15 nm, Aspect ratio 3:1 Peak absorption near 780 nm	None	Nanorods improved PA imaging contrast (GFP-expressing PC3N tumor, mouse dorsal window chamber).	[109]
Nanorod 10 × 35 nm	Au nanorod-MBs exhibited increased thermal expansion and over 10-fold greater amplitude of PA signal as compared with Au nanorods. Enhanced PA and pulse inversion images as compared with Au nanorods (gelatin flow phantom).	Enhanced PA and pulse inversion images (murine kidney model).	[115]
AuNP 3–4 nm Whole NP (αvβ3-Au nanobeacon) 150 nm	Characterization of the size of αvβ3-Au nanobeacon by DLS and AFM.	Sensitive and specific angiogenesis PA imaging (Matrigel-plug mouse model).	[116]

GFP, green fluorescent protein; MB, microbubble; DLS, dynamic light scattering; and AFM, atomic-force microscopy.