Encapsulation of Enzymes within Polymer Spheres To Create Optical Nanosensors for Oxidative Stress
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- 作者：Se-Hwa Kim ; Bumsang Kim ; Vamsi K. Yadavalli ; and Michael V. Pishko
- 刊名：Analytical Chemistry
- 出版年：2005
- 出版时间：November 1, 2005
- 年：2005
- 卷：77
- 期：21
- 页码：6828 - 6833
- 全文大小：738K
- 年卷期：v.77,no.21(November 1, 2005)
- ISSN：1520-6882
文摘
We describe the fabrication and characterization of poly(ethylene glycol) (PEG) hydrogel spheres containing theenzyme horseradish peroxidase (HRP) for application asoptical nanosensors for hydrogen peroxide. HRP wasencapsulated in PEG hydrogel spheres by reverse emulsion photopolymerization, yielding spheres with a sizerange from 250 to 350 nm. Encapsulated HRP activityand sensitivity to hydrogen peroxide were investigated bythe Amplex Red assay based on the fluorescence responseas a function of H2O2. These HRP-loaded spheres werethen introduced to murine macrophages with Amplex Redin the culture media. After phagocytosis, the biocompatibility of spheres was determined by live cell staining usingcalcein AM (5 
M). The HRP-loaded PEG hydrogelspheres were activated (i.e., fluorescent oxidized AmplexRed produced within the spheres) by oxidative stressessuch as exogenous H2O2 (100 M) and lipopolysaccharide (1 g/mL), which induced the production of endogenous peroxide inside macrophages. The results presented here indicate that after polymerization, the enzymeactivity of HRP was still maintained and that using theseHRP-containing nanospheres, peroxide production couldbe sensed locally within cells.
M). The HRP-loaded PEG hydrogelspheres were activated (i.e., fluorescent oxidized AmplexRed produced within the spheres) by oxidative stressessuch as exogenous H2O2 (100 M) and lipopolysaccharide (1 g/mL), which induced the production of endogenous peroxide inside macrophages. The results presented here indicate that after polymerization, the enzymeactivity of HRP was still maintained and that using theseHRP-containing nanospheres, peroxide production couldbe sensed locally within cells.