Fig. 3

Ultrasound enhancement imaging ability of O-CS-DOX NDs in vitro. a Schematic illustration of the in vitro imaging experimental setup; b ULtrasound contrast enhanced images of various concentrations of O-CS-DOX NDs. c Comparison of the contrast imaging abilities (signal to noise ratio, SNR) between various concentrations of O-CS-DOX NDs, asterisks (*) denote significant differences (**p < 0.01)