Related Experiment Video
Updated: Jun 3, 2026
Pulsed Laser Diode-Based Desktop Photoacoustic Tomography for Monitoring Wash-In and Wash-Out of Dye in Rat Cortical Vasculature
Published on: May 30, 2019
Near-infrared dye-loaded PLGA nanoparticles prepared by spray drying for photoacoustic applications
Yvonne Kohl1, Christian Kaiser, Wolfgang Bost
1Fraunhofer Institute for Biomedical Engineering, St Ingbert, Germany.
Introduction:
Nanoparticulate contrast agents are of great interest for diagnostic applications with high resolution in medicine. Here we present polymer-based degradable nanoparticles exhibiting a near infrared (NIR) absorption suitable for photoacoustic imaging.
Methods:
The nanoparticles were prepared by incorporation of indocyanine green (ICG) as NIR dye in poly[(rac-lactide)-co-glycolide] (PLGA) via an optimized spray drying process. By application of a multi-step centrifugation protocol, two different size fractions were achieved. The biocompatibitilty of the nanoparticles was tested in 2D cell cultures (human hepatocarcinoma cells and monkey kidney cells) using WST-1, BrdU and LDH assay.
Results:
Spherical particles were obtained with a good yield (>81%), showing a high NIR-dye encapsulation efficiency (>98%). By multi-step centrifugation, two different size fractions with a mean diameter of 640 nm and 390 nm were obtained. Cytotoxicity studies of the synthesized ICG-loaded PLGA particles were performed. No cytotoxic effect on metabolic activity, proliferation, or membrane integrity was observed.
Conclusion:
The high optical absorption at the relevant NIR-wavelength around 800 nm in combination with absence of cytotoxicity qualifies the ICG-loaded PLGA particles as promising candidates for degradable photoacoustic contrast agents.
