FITC Doped Rattle-Type Silica Colloidal Particle-Based Ratiometric Fluorescent Sensor for Biosensing and Imaging of Superoxide Anion

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• 作者：Ying Zhou ; Jie Ding ; Tingxizi Liang ; E. S. Abdel-Halim ; Liping Jiang ; Jun-Jie Zhu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：March 16, 2016
• 年：2016
• 卷：8
• 期：10
• 页码：6423-6430
• 全文大小：430K
• ISSN：1944-8252

文摘

Fluorescent nanosensors have been widely applied in recognition and imaging of bioactive small molecules; however, the complicated surface modification process and background interference limit their applications in practical biological samples. Here, a simple, universal method was developed for ratiometric fluorescent determination of general small molecules. Taking superoxide anion (O₂^•–) as an example, the designed sensor was composed of three main moieties: probe carrier, rattle-type silica colloidal particles (mSiO₂@hmSiO₂ NPs); reference fluorophore doped into the core of NPs, fluorescein isothiocyanate (FITC); fluorescent probe for superoxide anion, hydroethidine (HE). In the absence of O₂^•–, the sensor just emitted green fluorescence of FITC at 518 nm. When released HE was oxidized by O₂^•–, the oxidation product exhibited red fluorescence at 570 nm and the intensity was linearly associated with the concentration of O₂^•–, while that of reference element remained constant. Accordingly, ratiometric determination of O₂^•– was sensitively and selectively achieved with a linear range of 0.2–20 μM, and the detection limit was calculated as low as 80 nM. Besides, the technique was also successfully applied for dual-emission imaging of O₂^•– in live cells and realized visual recognition with obvious fluorescence color change in normal conditions or under oxidative stress. As long as appropriate reference dyes and sensing probes are selected, ratiometric biosensing and imaging of bioactive small molecules would be achieved. Therefore, the design could provide a simple, accurate, universal platform for biological applications.