(a) Molecular structures of the porphyrin–phospholipid conjugates 39 investigated by Lovell et al. (167), Jin et al. (168), Ng et al. (169) and 40 investigated by Huynh et al. (101, 170); (b - e) In vivo imaging in a KB tumor xenograft 10–30 seconds post intravenous injection of bimodal (b, c) and trimodal (d, e) microbubbles derived from 40. US B-mode images show the soft tissue contrast of the tumor, US contrast mode and PA images illustrate the infusion of microbubbles (Scale bar 1 mm). Reproduced with permission from ref. 170. Copyright 2014 American Chemical Society.