The variety of nanoparticles developed by numerous investigators has presented a diverse platform for various optical imaging applications in biomedicine. We have previously reported that the FDA-approved chromophore Indocyanine Green (ICG) can be successfully encapsulated by cross-linked poly-allylamine hydrochloride (PAH)-Disodium Monophosphate (Na₂HPO₄) to form a nanoparticle for near-infrared imaging applications. The diameter of the constructs is dependent on the charge ratio between the polymer and salt used to encapsulate the chromophore. Modifications of the synthesis methods can alter the photophysical properties of the capsules, either through the adjustment of the charge ratio between PAH and Na₂HPO₄ or concentration of ICG successfully impregnated into the capsule. Through understanding the effects of tuning the nanoparticle properties, the photophysical characteristics of the constructs can be optimized. Here we present the results of adjusting the diameter of the nanoparticle and amount of ICG on the hydrodynamic diameters, absorption and fluorescence characteristics, and the relative fluorescence quantum yield. Optimizing the photophysical properties of the constructs can lead to increased imaging sensitivity and contrast for potential translational applications, including tumor imaging, which may utilize these nanoconstructs.

Date Published: 5 March 2014
PDF: 6 pages
Proc. SPIE 8956, Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications VI, 89560W (5 March 2014); doi: 10.1117/12.2042298

Published in SPIE Proceedings Vol. 8956:
Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications VI
Samuel Achilefu; Ramesh Raghavachari, Editor(s)