title: A general strategy for biocompatible, high-effective upconversion nanocapsules based on triplet-triplet annihilation.
abstract: A general strategy for constructing high-effective upconversion nanocapsules based on triplet-triplet annihilation (TTA) was developed by loading both sensitizer and annihilator into BSA-dextran stabilized oil droplets. This strategy can maintain high translational mobility of the chromophores, avoid luminescence quenching of chromophore by aggregation, and decrease the O2-induced quenching of TTA-based upconversion emission. Pt(II)-tetraphenyl-tetrabenzoporphyrin (PtTPBP) and BODIPY dyes (BDP-G and BDP-Y with the maximal fluorescence emission at 528 and 546 nm, respectively) were chosen as sensitizer/annihilator couples to fabricate green and yellow upconversion luminescent emissive nanocapsules, named UCNC-G and UCNC-Y, respectively. In water under the atmospheric environment, interestingly, UCNC-G and UCNC-Y exhibit intense upconversion luminescence (UCL) emission (λex = 635 nm) with the quantum efficiencies (ΦUCL) of 1.7% and 4.8%, respectively, whereas very weak UCL emission (ΦUCL < 0.1%) was observed for the corresponding previous reported SiO2-coating nanosystems because of aggregation-induced fluorescence quenching of annihilators. Furthermore, application of theses upconversion nanocapsules for high-contrast UCL bioimaging in vivo of living mice without removing the skin was demonstrated under 635-nm excitation with low power density of 12.5 mW cm(-2).
authors: Department of Chemistry & The State Key Laboratory of Molecular Engineering of Polymers & Institute of Biomedicine Science, Fudan University , Shanghai, 200433, P. R. China.
authors: Qian
authors: Q
authors: Liu
authors: Baoru
authors: B
authors: Yin
authors: Tianshe
authors: T
authors: Yang
authors: Yongchao
authors: Y
authors: Yang
authors: Zhen
authors: Z
authors: Shen
authors: Ping
authors: P
authors: Yao
authors: Fuyou
authors: F
authors: Li
mesh_terms: D000818:Animals; D001896:Boron Compounds / Q000737:chemistry*; D002214:Capsules / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D049408:Luminescent Agents / Q000737:chemistry; D051379:Mice; D046529:Microscopy, Electron, Transmission; D057054:Molecular Imaging; D015394:Molecular Structure; D053769:Nanocapsules / Q000737:chemistry*; D009821:Oils / Q000737:chemistry; D010984:Platinum / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D012995:Solubility; D013024:Soybean Oil / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D001896:Boron Compounds; D002214:Capsules; D049408:Luminescent Agents; D053769:Nanocapsules; D009821:Oils; D014867:Water; D010984:Platinum; D012822:Silicon Dioxide; D013024:Soybean Oil