Optical detection of indocyanine green encapsulated biocompatible poly (lactic-co-glycolic) acid nanoparticles with photothermal optical coherence tomography

Department of Biomedical Engineering, Oregon Health and Science University, 3303 SW Bond Ave., Portland, Oregon 97239, USA.
Optics Letters (Impact Factor: 3.29). 03/2012; 37(5):981-3. DOI: 10.1364/OL.37.000981
Source: PubMed


We describe a functional imaging paradigm that uses photothermal optical coherence tomography (PT-OCT) to detect indocyanine green (ICG)-encapsulated biocompatible poly(lactic-co-glycolic) acid (PLGA) nanoparticles embedded in highly scattering tissue phantoms with high resolution and sensitivity. The ICG-loaded PLGA nanoparticles were fabricated using a modified emulsification solvent diffusion method. With a 20 kHz axial scan rate, PT-OCT based on spectral-domain interferometric configuration at 1310 nm was used to detect phase changes induced by a 808 nm photothermal excitation of ICG-encapsulated PLGA nanoparticles. An algorithm based on Fourier transform analysis of differential phase of the spectral interferogram was developed for detecting the depth resolved localized photothermal signal. Excellent contrast difference was observed with PT-OCT between phantoms containing different concentrations of ICG-encapsulated PLGA nanoparticles. This technique has the potential to provide simultaneous structural and molecular-targeted imaging with excellent signal-to-noise for various clinical applications.

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    • "Functional extensions of OCT, including magneto-motive (MMOCT) [3,4], spectroscopic [5–7], pump-probe [8,9], and photothermal OCT (PT-OCT), have demonstrated molecular contrast. Specifically, PT-OCT has recently received much attention [10–19] for a number of reasons. First, PT-OCT is able to identify and separate absorbing targets from the scattering background through active detection of photothermal heating [20] (which is also independent of tissue mechanical properties, unlike MMOCT). "
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