Fig. 6

Monitoring different nanoprobe accumulation with photoacoustic imaging. A Heat map of NP accumulation in tumors in PA-US overlay images respectively with different nanoprobe into mice bearing 4T1 tumors after 0 h, 2 h, 6 h, 8 h and 24 h (n = 3). B In vivo ultrasound image of a subcutaneous implanted 4T1 tumor. C Heat map of PA signals from targeted nanoprobe injected in mice implanted with 4T1 tumor (green). D Heat map of oxygenated hemoglobin (red) and deoxygenated hemoglobin (blue) of the same 4T1 tumor. E Overlaid with ultrasound image and targeted nanoprobe, oxygenated hemoglobin, and deoxygenated hemoglobin PA signals. F Average PA intensity increment at 850 nm as a function post-injection time with different nanoprobe into mice bearing 4T1 tumors after 0 h, 2 h, 4 h, 6 h, 8 h, 24 h, and 48 h (n = 3). Error bars represent standard deviation. *p < 0.05. G In vivo T1WI and T2WI of 4T1 tumors at various time points after intravenous injection of Au@FePt nanoprobe and FePt nanoprobe