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Facile Synthesis of pH‐sensitive Germanium Nanocrystals with High Quantum Yield for Intracellular Acidic Compartment Imaging
Author(s) -
Li Feng,
Wang Jing,
Sun Shuqing,
Wang Hai,
Tang Zhiyong,
Nie Guangjun
Publication year - 2015
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201402743
Subject(s) - nanocrystal , photoluminescence , quantum yield , fluorescence , germanium , quantum dot , materials science , nanotechnology , biosensor , aqueous solution , chemical engineering , chemistry , optoelectronics , silicon , organic chemistry , physics , quantum mechanics , engineering
A green‐light emitting germanium nanocrystal‐based biosensor to monitor lysosomal pH changes is developed. The Ge nanocrystals are synthesized in an aqueous solution with a significantly enhanced photoluminescence quantum yield of 26%. This synthesis involves a facile solution based route which avoided the use of toxic or environmentally unfriendly agents. Importantly, the photoluminescence intensity of the synthesized Ge nanocrystals is particularly sensitive to changes in pH between 5 and 6. When incubated with cultured cells, the nanocrystals are internalized and subsequently translocated via the lysosomal pathway, and the Ge nanocrystals' fluorescence are greatly enhanced, even when the lysosomal pH is only slightly increased. These results reveal that the Ge nanocrystals possess high pH sensitivity compared to a commercially available dye, LysoSensor Green DND‐189. The fluorescent properties of the Ge nanocrystals are demonstrated to be dependent on both the crystal form and their surface chemistry. The superior fluorescence properties and bioapplicability of the Ge nanocrystals makes them a promising intracellular bioimaging probe for monitoring various pH‐sensitive processes in cells.