title: Ischemic brain imaging using fluorescent gold nanoprobes sensitive to reactive oxygen species.
abstract: Fluorescein-labeled hyaluronic acids (HA) were immobilized on gold nanoparticles for reactive oxygen species (ROS) detection. The efficacy of HA immobilized gold nanoparticles (HHAuNPs) was evaluated in a stroke animal model. The stroke rat model was produced by transient middle cerebral artery occlusion (MCAO), which induced transient ischemia and reperfusion (I/R) in the brain. The increase of ROS in the I/R brain was confirmed by TBARS assay with the brain extracts. For brain imaging, HHAuNPs were injected into the rat brain 1 h before transient MCAO. Five hours after the injection, the rats were sacrificed and the brains were subjected to imaging analysis. The results showed that stronger signals were detected in the I/R brains than in the normal brains. To identify the time window for effective detection of ROS, HHAuNPs were injected into the post-ischemic rat brains at various time points. The results showed that ROS level reached a maximum at 24 h after the transient MCAO. Also, a live imaging study was performed with HHAuNPs in the normal and I/R animals. The results confirmed that ROS level increased in the I/R animal group with time, while the signal was decreased in the normal animal group. Together, our results suggest that HHAuNPs may be useful to monitor ROS level in the ischemic brain and to identify the infarct areas in ischemic brains for the treatment of stroke.
authors.affiliation: Department of Bioengineering, College of Engineering, Hanyang University, Seoul 133-791, Republic of Korea.
authors.forename: Hyesun
authors.initials: H
authors.lastname: Hyun
authors.forename: Kyuri
authors.initials: K
authors.lastname: Lee
authors.forename: Kyung Hyun
authors.initials: KH
authors.lastname: Min
authors.forename: Pureum
authors.initials: P
authors.lastname: Jeon
authors.forename: Kwangmeyung
authors.initials: K
authors.lastname: Kim
authors.forename: Seo Young
authors.initials: SY
authors.lastname: Jeong
authors.forename: Ick Chan
authors.initials: IC
authors.lastname: Kwon
authors.forename: Tae Gwan
authors.initials: TG
authors.lastname: Park
authors.forename: Minhyung
authors.initials: M
authors.lastname: Lee
mesh_terms: D000818:Animals; D001921:Brain / Q000098:blood supply / Q000378:metabolism; D002545:Brain Ischemia / Q000378:metabolism* / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D005453:Fluorescence; D006046:Gold / Q000008:administration & dosage* / Q000737:chemistry; D006820:Hyaluronic Acid / Q000737:chemistry; D020244:Infarction, Middle Cerebral Artery; D008297:Male; D053768:Metal Nanoparticles / Q000008:administration & dosage* / Q000737:chemistry; D061848:Optical Imaging; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D017392:Thiobarbituric Acid Reactive Substances; D006046:Gold; D006820:Hyaluronic Acid
keywords: Ischemia–reperfusion; Live imaging; Nanoparticles; Reactive oxygen species; Stroke