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. Author manuscript; available in PMC: 2011 Dec 6.
Published in final edited form as: Mol Pharm. 2010 Oct 29;7(6):2006–2019. doi: 10.1021/mp100280b

Figure 6.

Figure 6

Change in fluorescence intensity in the core (0.25r), intermediate layers (0.50r and 0.75r), and surface (1.00r) of MCF-7 spheroids by FITC-loaded, 40 nm particles with carboxylic acid surface groups and exposed to pulsed US at (A) 10% DC, (B) 20 % DC, (C) 40% DC, and (D) 50% DC compared to spheroids that were not exposed to US. Fifty μl of Optison microbubbles were added to the spheroids' solution before US exposure. All results are the average of 15 samples ± the standard error of the mean. The * indicates p < 0.05, ** p < 0.01, and *** p < 0.005 when comparing the test and control groups. (E) A representative phase contrast image of MCF-7 spheroids suspended in PBS, mixed with 40 nm FITC-loaded particles and 50 μl of Optison microspheres, and exposed to US (center frequency 1 MHz, acoustic pressure 0.5 MPa, pulse repition frequency 10 Hz, and duty cycle 50%) for 60 seconds. The image clearly shows the fragmentation and loss of integrity of the irradiated spheroid.