Fluorescent microparticles for sensing cell microenvironment oxygen levels within 3D scaffolds
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Miguel A. Acosta, Patrick Ymele-Leki, Yordan V. Kostov, Jennie B. Leach, Fluorescent microparticles for sensing cell microenvironment oxygen levels within 3D scaffolds, Biomaterials Volume 30, Issue 17, June 2009, Pages 3068-3074, https://doi.org/10.1016/j.biomaterials.2009.02.021
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Attribution-NonCommercial-NoDerivs 3.0 United States
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This item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.
Abstract
We present the development and characterization of fluorescent oxygen-sensing microparticles designed for measuring oxygen concentration in microenvironments existing within standard cell culture and transparent three-dimensional (3D) cell scaffolds. The microparticle synthesis employs poly(dimethylsiloxane) to encapsulate silica gel particles bound with an oxygen-sensitive luminophore as well as a reference or normalization fluorophore that is insensitive to oxygen. We developed a rapid, automated and non-invasive sensor analysis method based on fluorescence microscopy to measure oxygen concentration in a hydrogel scaffold. We demonstrate that the microparticles are non-cytotoxic and that their response is comparable to that of a traditional dissolved oxygen meter. Microparticle size (5–40 μm) was selected for microscale-mapping of oxygen concentration to allow measurements local to individual cells. Two methods of calibration were evaluated and revealed that the sensor system enables characterization of a range of hypoxic to hyperoxic conditions relevant to cell and tissue biology (i.e., pO₂ 10–160 mm Hg). The calibration analysis also revealed that the microparticles have a high fraction of quenched luminophore (0.90 ± 0.02), indicating that the reported approach provides significant advantages for sensor performance. This study thus reports a versatile oxygen-sensing technology that enables future correlations of local oxygen concentration with individual cell response in cultured engineered tissues.