To examine the ability of NP-ICG-HA todetect cancer cells, CD44 expressing 4T1 cells50 were incubated with NP-ICG-HA, NP-ICG, or ICG at the sameICG fluorescence intensities for 2 h at 37 °C followed by thoroughwashing with PBS to remove the unbonded particles. Here, CD44 is linked to cancer.