Table 3.

Representative exogenous PA contrast agents with applications in drug delivery and monitoring.

Photoacoustic Agent	Description	Wavelength (nm)	Target	Image-Guided Outcome	Reference
Semiconducting Polymer Nanoparticles	Photothermal SPNs doped with fullerene	750	Breast Tumor	Photothermal therapy	Lyu et al. 2016 119
Nanonaps	Frozen micelles of hydrophobic, napthalocyanine dyes (~20 nm diameter)	600, 707, 793, 863 (Tunable)	Intestine	Diagnosis/treatment of intestinal motility disorders	Zhang et al. 2014 120
MoS2 Nanosheets	PEGylated, 2-D nanosheets loaded with photodynamic Ce6	800	Breast Tumor	Photothermal therapy, photodynamic therapy	Liu et al. 2014 121
RbxWO3 Nanorods	Rubidium tungsten bronze nanorods with doxorubicin payload, 20-40 nm x 5 nm	808	Breast Tumor	Combined chemo/photo-thermal therapy	Tian et al. 2014 122
Gold Nanocages	Gold nanocages loaded with1-tetradecanol (phase-change)and organic dyes	750	Non-specific	HIFU/Temperature-triggered drug release and monitoring	Moon et al. 2011 123
Fucoidan CappedGold Nanoparticles	Gold nanoparticles coatedwith fucoidan and doxorubicin	566	Breast Tumor	Chemotherapy	Manivasagan et al. 2016 124
Perfluorocarbon Nanodroplets	Perfluorocarbon nanodropletsloaded with gold nanorods and paclitaxel	770	Cervical Tumor	Combined chemo/photo-acoustic therapy	Zhong et al. 2016 125
Porphyrinoid-LoadedPLGA Nanoparticles	Poly(lactic-co-glycolic) acid nanoparticles loaded withporphyrinoid macrocycles	910	Uranium	Quantification of in vivo uranium exposure	Ho et al. 2015 126
Optode Nanosensors	Intradermal injectable nanosensorcontaining a crown ether ionophoreand a chromoionophore	515, 660	Lithium	Drug monitoring of systemiclithium dose	Cash et al. 2015 127
Methylene Blue or Nile Blue	Cellulose-based, PEG-infused substrates containing Nile Blue	680	Heparin	Drug monitoring of systemic heparin dose	Jeevarathinam et al. 2018 128