Table 3.

Summary of dual-labeled peptide agents for nuclear/NIRF imaging^a

Target	Chelator	NIRF Dye	Radionuclide	Reaction buffer	pH	Heating conditions	Dose prepared or administered	Optical stability (HPLC)	Spectral properties evaluated	Conclusions	Refs
Integrin αvβ3	DTPA	IRDye 800CW	In-111	0.1 M NaOAc	5.5	25°C, 15 min	Administered	NG	Ex/Em spectra	• Provided a comparative assessment of optical intensified charge-coupled device camera image in comparison with nuclear imaging	[37, 62]
							• Amount: 5 nmol			• Showed optical imaging is highly sensitive to photons emanating from superficial depths
							• Activity: 3.3 MBq			• Demonstration of feasibility of nuclear/NIRF imaging with a single agent and proposed path for translation of NIR fluorescence through dual-labeling
Integrin αvβ3	DFO	Cypate	Cold Ga, In, Cu	Water/acetonitrile	NG	NG	NG	NG	Extinction coefficient	• Developed a multifunctional imaging probe for NIRF imaging, delivery of DFO to tumor cells, and potential chelation of radiometals	[38]
									Ex/Em spectra	• Demonstrated that a targeted therapeutic that could be monitored by multimodal imaging
										• Developed a novel platform for optimization of multimodal imaging agents
Integrin αvβ3	DOTA	Cypate	In-111	0.1 M NaOAc	5.5	80°C, 1 h	Administered	NG	NG	• Developed a DOTA/NIRF RGD analog for dual-labeling	[39]
							• Amount: 140–800 pmol			• Agent was prepared in high specific activity and has potential use with different radiometals due to presence of DOTA as chelator
							• Activity: 1.5–7.4 MBq			• Tumors visualization by both nuclear/NIRF imaging concurred with reports from earlier studies.
SSTR	DOTA	Cypate	Cu-64, Lu-177	0.1 M NaOAc	5.5	25°C; 80°C for 80 min	Prepared (64Cu)	NG	Ex/Em spectra	• Developed a dual-labeled SSTR targeting agent for nuclear/NIRF imaging	[46]
							• Amount: 1 nmol		Quantum yield (performed after cold-labeling)	• Utilized therapeutic radionuclides in multi-modal monomolecular imaging agent (MOMIA) dual-labeling strategy
							• Activity: 12.3 MBq			• Fluorescent properties were retained after labeling with metal.
							Administered (64Cu)			• Excellent agreement between the optical and radiochemical biodistribution demonstrates the utility of MOMIA platform
							• Amount: 12 pmol
							• Activity: 0.2 MBq
MMP	DOTA	IRDye 800CW	Cu-64	0.1 M NaOAc	6	50°C, 1 h	Prepared	Yes	NG	• Application of multimodal imaging to detect new bone formation in vivo	[64]
							• Amount: 6–35 nmol			• PET/NIRF imaging served as an early indicator of new bone formation prior to anatomical changes being detectable by CT
							• Activity: 37–74 MBq
							Administered
							• Amount: 6 nmol
							• Activity: 7.4 MBq
MMP	DOTA	IRDye 800CW	Ga-68	0.1 M NaOAc	4	95°C, 10 min	Prepared	Yes	Extinction coefficient	• Developed a dual-labeled nuclear/NIRF imaging agent using generator-produced 68Ga	[49]
							• Amount: 35 nmol		Quantum yield (performed after radiolabeling)	• Chemical, radiochemical, and optical stability was shown
							• Activity: 55.5 MBq			• In vivo PET/NIRF imaging demonstrated feasibility of using 68Ga with NIRF as a dual-labeling strategy for peptides or small molecules
							Administered
							• Amount: 6 nmol
							• Activity: 7.4 MBq
Interleukin-11 receptor-α	DTPA	IR783	In-111	0.1 M NaOAc	NG	25°C, 30 min	Administered	NG	Ex/Em spectra	• Applied dual-labeling strategy for nuclear/NIRF imaging of IL-11Rα without altering targeting capability of peptide	[50]
							• Amount: 2 nmol			• 111In chelation showed no quenching of fluorescence
										• Preliminary imaging by optical and nuclear methods were consistent
Caspase-3	DOTA	LS-276	Cu-64	0.1 M NH4OAc	5.5	60°C, 30 min	Prepared	NG	NG	• Developed a multimodal imaging agent activated by enzymatic cleavage	[51]
							• Amount: 1.3 nmol			• Results demonstrate the feasibility of using radionuclide imaging for localizing and quantifying the distribution of molecular probes and optical imaging for reporting the functional status of diagnostic enzymes
							• Activity: 17.4 MBq
Hydroxyapatiteb	N3S	IRDye 800CW	Tc-99 m	DMSO	NG	25°C, 1 h	Prepared	NG	Ex/Em spectra	• Developed a bisphosphonate-based dual modality nuclear/NIRF contrast agent for detecting breast cancer microcalcifications	[52]
							• Specific activity: 6,250 Ci/mmol		Quantum yield	• Described 99mTc labeling effects on spectral properties of IRDye 800CW
							Administered			• Demonstrated nearly identical total body clearance compared to the nuclear “gold standard” 99mTc-MDP
							• Amount: 25 nmol
							• Activity: 18.5 MBq

^a NG not given

^bUsed a nonpeptide targeting moiety