Photoacoustic Flow System for the Detection of Ovarian Circulating Tumor Cells Utilizing Copper Sulfide Nanoparticles.

The development of cell-specific photoacoustic (PA) contrast agents within systems of fluidic flow provides opportunities for the accurate detection of early stage cancer metastasis. Despite the promise of exogenous contrast agents for use in clinical settings, applications are currently limited by both material biocompatibility and target specificity. In this study, folic acid functionalized copper sulfide nanoparticles (FA-CuS NPs) are synthesized to enable ovarian-cancer-specific binding and PA detection in a custom flow system. Folate receptors, known to be overexpressed on the surface of ovarian cancer cells, have remained an ideal candidate for specific targeting through functionalization on nanoparticles and other contrast agents. In combination with copper sulfide nanoparticles' strong absorbance in the near-infrared (NIR), these FA-CuS NPs are an ideal contrast agent capable of being detected by photoacoustic flow cytometry. For the first time, this study shows a potential PA contrast agent to accurately identify ovarian circulating tumor cells in flow.