title: FITC Doped Rattle-Type Silica Colloidal Particle-Based Ratiometric Fluorescent Sensor for Biosensing and Imaging of Superoxide Anion.
abstract: 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.
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation of Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210093, P. R. China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation of Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210093, P. R. China.|Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, China-America Cancer Research Institute, Guangdong Medical University , Dongguan 523808, P. R. China.
authors.forename: Jie
authors.initials: J
authors.lastname: Ding
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation of Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210093, P. R. China.
authors.forename: Tingxizi
authors.initials: T
authors.lastname: Liang
authors.affiliation: Chemistry Department, College of Science, King Saud University , Riyadh 11451, P.O. Box 2455, Kingdom Saudi Arabia.
authors.forename: E S
authors.initials: ES
authors.lastname: Abdel-Halim
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation of Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210093, P. R. China.
authors.forename: Liping
authors.initials: L
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation of Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210093, P. R. China.
authors.forename: Jun-Jie
authors.initials: JJ
authors.lastname: Zhu
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D003102:Colloids; D016650:Fluorescein-5-isothiocyanate / Q000737:chemistry / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D057054:Molecular Imaging / Q000379:methods*; D012822:Silicon Dioxide / Q000737:chemistry / Q000494:pharmacology; D013481:Superoxides / Q000032:analysis / Q000378:metabolism
chemical_list: D003102:Colloids; D013481:Superoxides; D012822:Silicon Dioxide; D016650:Fluorescein-5-isothiocyanate
keywords: FITC@mSiO2@hmSiO2; bioactive small molecules; hydroethidine; ratiometric fluorescent sensor; superoxide anion