Effect of nano-encapsulation on photophysical properties of ICG

Abstract

Indocyanine green (ICG) is an FDA-approved infrared chromophore used for various biomedical applications such as cardiac and hepatic function evaluation, and ophthalmic angiography. Despite its clinical applications, freely dissolved ICG binds non-specifically to various plasma proteins resulting in changes in its near infrared (NIR) emission properties and rapid elimination from the vasculature. To overcome these shortcomings, we have encapsulated ICG within polymeric nano-constructs composed of poly allylamine hydrochloride (PAH) cross-linked with di-sodium hydrogen phosphate (Na 2 HPO 4 ). To optimize the photophysical properties of nano-encapsulated ICG (NE-ICG) for clinical imaging applications, we report measurements of fluorescent quantum yield (φ) of NE-ICG. Specifically, we constructed capsules of three different diameters (~130, ~240, and ~450 nm). Our preliminary results indicate that NE-ICG shows less quantum yield compared to freely-dissolved ICG. We determined that the 240 nm diameter capsule to have the highest φ and 450 nm diameter capsules to have the least φ at room temperature.

Formulation of long-wavelength indocyanine green nanocarriers

“…1(d)], which fall into the optical imaging window (700 to 1450 nm), its long history of use in humans, and its approval by the FDA. Therefore, there is considerable interest in incorporating ICG into nanoscale carriers such as liposomes, 25,26 micelles, 15,[27][28][29][30] nanocapsules, 31,32 and mesocapsules, 33 as well as in more complex formulations for dual purpose diagnostics and therapy, 11,34 multimodal imaging 35 systems that can enhance the apparent quantum yield (QY) of ICG to several times its natural QY in water, 34 ICG embedded within hydrophobic polymers, 36,37 and mesoporous materials. 38 ICG has been incorporated into these carriers either as the pure molecule, 28 as a complex with a hydrophobic cationic species, 29 or as a conjugate to polymers.…”

Development of anti-HER2 conjugated ICG-loaded polymeric nanoparticles for targeted optical imaging of ovarian cancer

“…ICG-NCs were synthesized by ionic cross-linking between Pollyallylamine hydrochloride chains and sodium phosphate and subsequent diffusion-mediated ICG loading, as reported in previous publications [8][9][10][11][12][13][14][15][16][17] . Before functionalization of ICG-NCs with anti-HER2, the surface of ICG-NCs was coated with single and double aldehyde terminated PEG 8 .…”

“…We have engineered polymer-based nanocapsules doped with Indocyanine green (ICG), an FDA approved chromophore [8][9][10][11][12][13][14][15][16][17] . Certain advances associated with our ICG-doped nanocapsules (ICG-NCs) are: 1) spontaneous selfassembly via green chemistry; 2) ability to produce capsules with a broad range of diameters from 60 nm to 1 µm; and 3) multi-functionality through covalent coupling of targeting moieties to the surface of ICG-NCs for site-specific, deep optical imaging, and laser-based phototherapy.…”

Gold nanoparticle-based nanoprobes with enhanced tumor targeting and photothermal/photodynamic response for therapy of osteosarcoma

“…The tricarbonyl cyanine dye, indocyanine green (ICG), is approved by the US Food and Drug Administration as a NIR photosensitizer for clinical imaging and diagnosis [21,22]. However, the ICG drug molecule has several inherent disadvantages, including poor stability and low thermal stability in the aqueous environment, rapid blood clearance, and low quantum yield [23][24][25]. These disadvantages severely limit the application of ICG in fluorescence imaging and photodynamic therapy.…”