title: CdSe/CdS-quantum rods: fluorescent probes for in vivo two-photon laser scanning microscopy.
abstract: CdSe/CdS-Quantum-dots-quantum-rods (QDQRs) with an aspect ratio of ∼ 6 are prepared via the seeded growth method, encapsulated within a shell of crosslinked poly(isoprene)-block-poly(ethylene glycol) (PI-b-PEG) diblock copolymer, and transferred from the organic phase into aqueous media. Their photoluminescence quantum yield (PLQY) of 78% is not compromised by the phase transfer. Within a period of two months the PLQY of QDQRs in aqueous solution at neutral pH decreases only slightly (to ∼ 65%). The two-photon (TP) action cross sections of QDQRs (∼ 10(5) GM) are two orders of magnitude higher than those of CdSe/CdS/ZnS-core/shell/shell quantum dots (QDs, ∼ 10(3) GM) with comparable diameter (∼ 5 nm). After applying PI-b-PEG encapsulated QDQRs onto the small intestinal mucosa of mice in vivo, their strong red fluorescence can easily be observed by two-photon laser scanning microscopy (TPLSM) and clearly distinguished from autofluorescent background. Our results demonstrate that PI-b-PEG encapsulated CdSe/CdS-QDQRs are excellent probes for studying the uptake and fate of nanoparticles by two-photon imaging techniques in vivo.
authors: Institute of Physical Chemistry, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany. tobias.vossmeyer@chemie.uni-hamburg.de horst.weller@chemie.uni-hamburg.de.
authors: Jelena
authors: J
authors: Dimitrijevic
authors: Lisa
authors: L
authors: Krapf
authors: Christopher
authors: C
authors: Wolter
authors: Christian
authors: C
authors: Schmidtke
authors: Jan-Philip
authors: JP
authors: Merkl
authors: Tobias
authors: T
authors: Jochum
authors: Andreas
authors: A
authors: Kornowski
authors: Anna
authors: A
authors: Schüth
authors: Andreas
authors: A
authors: Gebert
authors: Gereon
authors: G
authors: Hüttmann
authors: Tobias
authors: T
authors: Vossmeyer
authors: Horst
authors: H
authors: Weller
mesh_terms: D000818:Animals; D019187:Cadmium Compounds / Q000737:chemistry; D005456:Fluorescent Dyes / Q000138:chemical synthesis; D007422:Intestines / Q000166:cytology; D008422:Materials Testing; D051379:Mice; D018613:Microscopy, Confocal / Q000379:methods*; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry / Q000648:ultrastructure; D010316:Particle Size; D011108:Polymers / Q000737:chemistry; D045663:Quantum Dots; D015203:Reproducibility of Results; D018036:Selenium Compounds / Q000737:chemistry; D012680:Sensitivity and Specificity; D013440:Sulfides / Q000737:chemistry; D013499:Surface Properties
chemical_list: D019187:Cadmium Compounds; D005456:Fluorescent Dyes; D011108:Polymers; D018036:Selenium Compounds; D013440:Sulfides; C034939:cadmium sulfide; C058667:cadmium selenide