title: In situ conversion of porphyrin microbubbles to nanoparticles for multimodality imaging.
abstract: Converting nanoparticles or monomeric compounds into larger supramolecular structures by endogenous or external stimuli is increasingly popular because these materials are useful for imaging and treating diseases. However, conversion of microstructures to nanostructures is less common. Here, we show the conversion of microbubbles to nanoparticles using low-frequency ultrasound. The microbubble consists of a bacteriochlorophyll-lipid shell around a perfluoropropane gas. The encapsulated gas provides ultrasound imaging contrast and the porphyrins in the shell confer photoacoustic and fluorescent properties. On exposure to ultrasound, the microbubbles burst and form smaller nanoparticles that possess the same optical properties as the original microbubble. We show that this conversion is possible in tumour-bearing mice and could be validated using photoacoustic imaging. With this conversion, our microbubble can potentially be used to bypass the enhanced permeability and retention effect when delivering drugs to tumours.
authors.affiliation: 1] Princess Margaret Cancer Center and Techna Institute, University Health Network, Toronto, Ontario M5G 2M9, Canada [2] Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Huynh
authors.affiliation: Sunnybrook Health Sciences Center, Toronto, Ontario M4N 3M5, Canada.
authors.forename: Ben Y C
authors.initials: BY
authors.lastname: Leung
authors.affiliation: 1] Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada [2] Sunnybrook Health Sciences Center, Toronto, Ontario M4N 3M5, Canada.
authors.forename: Brandon L
authors.initials: BL
authors.lastname: Helfield
authors.affiliation: 1] Princess Margaret Cancer Center and Techna Institute, University Health Network, Toronto, Ontario M5G 2M9, Canada [2] Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada.
authors.forename: Mojdeh
authors.initials: M
authors.lastname: Shakiba
authors.affiliation: Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada.
authors.forename: Julie-Anne
authors.initials: JA
authors.lastname: Gandier
authors.affiliation: 1] Princess Margaret Cancer Center and Techna Institute, University Health Network, Toronto, Ontario M5G 2M9, Canada [2] Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario M5S 3M2, Canada [3] Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5G 1L7, Canada.
authors.forename: Cheng S
authors.initials: CS
authors.lastname: Jin
authors.affiliation: Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada.
authors.forename: Emma R
authors.initials: ER
authors.lastname: Master
authors.affiliation: 1] Princess Margaret Cancer Center and Techna Institute, University Health Network, Toronto, Ontario M5G 2M9, Canada [2] Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Wilson
authors.affiliation: 1] Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada [2] Sunnybrook Health Sciences Center, Toronto, Ontario M4N 3M5, Canada.
authors.forename: David E
authors.initials: DE
authors.lastname: Goertz
authors.affiliation: 1] Princess Margaret Cancer Center and Techna Institute, University Health Network, Toronto, Ontario M5G 2M9, Canada [2] Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada [3] Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario M5S 3M2, Canada [4] Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5G 1L7, Canada.
authors.forename: Gang
authors.initials: G
authors.lastname: Zheng
mesh_terms: D007089:Image Enhancement / Q000379:methods; D008422:Materials Testing; D045423:Microbubbles; D008856:Microscopy, Fluorescence / Q000379:methods*; D064847:Multimodal Imaging / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D061088:Photoacoustic Techniques / Q000379:methods; D011166:Porphyrins / Q000737:chemistry* / Q000528:radiation effects; D014463:Ultrasonography / Q000379:methods*
chemical_list: D011166:Porphyrins