Photoacoustic detection of cancer cells using targeted gold nanorod loaded PLGA nanoparticles

In this study, a phase-change contrast agent made of biodegradable polymer PLGA and loaded with gold nanorods (GNRs) and perfluorohexane were conjugated to an anti-HER2 antibody (Herceptin) for specific binding to breast cancer cells that overexpress HER2 receptors. The mean size of the nanoparticles (NPs) was about 500 nm. The targeting specificity of PLGA-GNR-Herceptin NPs was examined using fluorescent imaging, flow cytometry, and photoacoustic (PA) imaging. Flow cytometry results demonstrated that 53% DiD-positive staining was found in HER2-positive BT474 cells after incubation with nanoparticle/antibody conjugates for one hour, while only 3.8% DiD-positive staining was found in HER2-negative MDA-MB-231 cells, indicating receptor-specific binding of the conjugated PLGA NPs. This binding was confirmed by fluorescent imaging. The PA image enhancement with a 19-fold increase in the signal-to-noise ratio was also demonstrated in vitro using targeted NPs. This particle can be loaded with chemo drugs and may be a potential cancer biomarker and therapeutic agent using PA imaging guidance.