title: Poly β-cyclodextrin/TPdye nanomicelle-based two-photon nanoprobe for caspase-3 activation imaging in live cells and tissues.
abstract: Two-photon excitation (TPE) with near-infrared (NIR) photons as the excitation source has important advantages over conventional one-photon excitation (OPE) in the field of biomedical imaging. β-cyclodextrin polymer (βCDP)-based two-photon absorption (TPA) fluorescent nanomicelle exhibits desirable two-photon-sensitized fluorescence properties, high photostability, high cell-permeability and excellent biocompatibility. By combination of the nanostructured two-photon dye (TPdye)/βCDP nanomicelle with the TPE technique, herein we have designed a TPdye/βCDP nanomicelle-based TPA fluorescent nanoconjugate for enzymatic activity assay in biological fluids, live cells and tissues. This sensing system is composed of a trans-4-[p-(N,N-diethylamino)styryl]-N-methylpyridinium iodide (DEASPI)/βCDP nanomicelle as TPA fluorophore and carrier vehicle for delivery of a specific peptide sequence to live cell through fast endocytosis, and an adamantine (Ad)-GRRRDEVDK-BHQ2 (black hole quencher 2) peptide (denoted as Ad-DEVD-BHQ2) anchored on the DEASPI/βCDP nanomicelle's surface to form TPA DEASPI/βCDP@Ad-DEVD-BHQ2 nanoconjugate by the βCD/Ad host-guest inclusion strategy. Successful in vitro and in vivo enzymatic activities assay of caspase-3 was demonstrated with this sensing strategy. Our results reveal that this DEASPI/βCDP@Ad-DEVD-BHQ2 nanoconjugate not only is a robust, sensitive and selective sensor for quantitative assay of caspase-3 in the complex biological environment but also can be efficiently delivered into live cells as well as tissues and act as a "signal-on" fluorescent biosensor for specific, high-contrast imaging of enzymatic activities. This DEASPI/βCDP@Ad-DEVD-BHQ2 nanoconjugate provides a new opportunity to screen enzyme inhibitors and evaluate the apoptosis-associated disease progression. Moreover, our design also provides a methodology model scheme for development of future TPdye/βCDP nanomicelle-based two-photon fluorescent probes for in vitro or in vivo determination of biological or biologically relevant species.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University , Changsha 410082, People's Republic of China.
authors.forename: Huijuan
authors.initials: H
authors.lastname: Yan
authors.forename: Leiliang
authors.initials: L
authors.lastname: He
authors.forename: Wenjie
authors.initials: W
authors.lastname: Zhao
authors.forename: Jishan
authors.initials: J
authors.lastname: Li
authors.forename: Yue
authors.initials: Y
authors.lastname: Xiao
authors.forename: Ronghua
authors.initials: R
authors.lastname: Yang
authors.forename: Weihong
authors.initials: W
authors.lastname: Tan
mesh_terms: D000818:Animals; D053148:Caspase 3 / Q000378:metabolism*; D002470:Cell Survival; D004789:Enzyme Activation; D005260:Female; D005456:Fluorescent Dyes / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008823:Micelles; D049329:Nanostructures / Q000737:chemistry*; D017785:Photons; D011409:Propylene Glycols; D002583:Uterine Cervical Neoplasms / Q000201:enzymology*; D047392:beta-Cyclodextrins
chemical_list: D005456:Fluorescent Dyes; D008823:Micelles; D011409:Propylene Glycols; D047392:beta-Cyclodextrins; C507884:poly(beta-cyclodextrin); D053148:Caspase 3