Nanoscale Confinement and Fluorescence Effects of Bacterial Light Harvesting Complex LH2 in Mesoporous Silicas

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• 作者：Hideki Ikemoto ; Sumera Tubasum ; T枚nu Pullerits ; Jens Ulstrup ; Qijin Chi
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：February 14, 2013
• 年：2013
• 卷：117
• 期：6
• 页码：2868-2878
• 全文大小：616K
• 年卷期：v.117,no.6(February 14, 2013)
• ISSN：1932-7455

文摘

Many key chemical and biochemical reactions, particularly in living cells, take place in confined space at the mesoscopic scale. Toward understanding of physicochemical nature of biomacromolecules confined in nanoscale space, in this work we have elucidated fluorescence effects of a light harvesting complex LH2 in nanoscale chemical environments. Mesoporous silicas (SBA-15 family) with different shapes and pore sizes were synthesized and used to create nanoscale biomimetic environments for molecular confinement of LH2. A combination of UV鈥搗is absorption, wide-field fluorescence microscopy, and in situ ellipsometry supports that the LH2 complexes are located inside the silica nanopores. Systematic fluorescence effects were observed and depend on degree of space confinement. In particular, the temperature dependence of the steady-state fluorescence spectra was analyzed in detail using condensed matter band shape theories. Systematic electronic-vibrational coupling differences in the LH2 transitions between the free and confined states are found, most likely responsible for the fluorescence effects experimentally observed.