title: Biocompatible polypyrrole nanoparticles as a novel organic photoacoustic contrast agent for deep tissue imaging.
abstract: Photoacoustic tomography (PAT) has emerged as a hybrid, nonionizing imaging modality because of its satisfactory spatial resolution and high soft tissue contrast. Here, we demonstrate the application of a novel organic PAT contrast agent based on polypyrrole nanoparticles (PPy NPs). Monodisperse PPy NPs are ∼46 nm in diameter with strong absorption in the near-infrared (NIR) range, which allowed visualization of PPy NP-containing agar gel embedded in chicken breast muscle at a depth of ∼4.3 cm. Compared with PAT images based on the intrinsic optical contrast in mice, the PAT images acquired within 1 h after intravenous administration of PPy NPs showed the brain vasculature with greater clarity than hemoglobin in blood. Preliminary results showed no acute toxicity to the vital organs (heart, liver, spleen, lungs and kidneys) in mice following a single imaging dose of PPy NPs. Our results indicate that PPy NPs are promising contrast agents for PAT with good biocompatibility, high spatial resolution and enhanced sensitivity.
authors.affiliation: School of Life Sciences and Technology, Harbin Institute of Technology, Harbin 150080, China.
authors.forename: Zhengbao
authors.initials: Z
authors.lastname: Zha
authors.forename: Zijian
authors.initials: Z
authors.lastname: Deng
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Li
authors.forename: Changhui
authors.initials: C
authors.lastname: Li
authors.forename: Jinrui
authors.initials: J
authors.lastname: Wang
authors.forename: Shumin
authors.initials: S
authors.lastname: Wang
authors.forename: Enze
authors.initials: E
authors.lastname: Qu
authors.forename: Zhifei
authors.initials: Z
authors.lastname: Dai
mesh_terms: D000818:Animals; D001921:Brain / Q000098:blood supply / Q000473:pathology; D002533:Cerebral Angiography / Q000379:methods*; D002560:Cerebrovascular Circulation; D002645:Chickens; D003287:Contrast Media / Q000737:chemistry / Q000494:pharmacology; D008422:Materials Testing; D051379:Mice; D018482:Muscle, Skeletal / Q000098:blood supply / Q000473:pathology; D053758:Nanoparticles / Q000737:chemistry*; D061088:Photoacoustic Techniques / Q000379:methods*; D011108:Polymers / Q000737:chemistry / Q000494:pharmacology; D011758:Pyrroles / Q000737:chemistry / Q000494:pharmacology; D041622:Tomography, Optical / Q000379:methods*; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media; D011108:Polymers; D011758:Pyrroles; C067635:polypyrrole