Fig. 9. Acidic pH mediated activation of the photoacoustic property of pNIR@P@SA. pNIR@P@SA was spiked into sodium phosphate buffers (100 mM) of varying pH values pH 4.5–9.5 to a final concentration of 1 mg ml–1. Visual images and photoacoustic contrast for the solutions were recorded (A). The optoacoustic intensity was plotted over buffer pH (B).
