Wang, LinAcosta, Miguel A.Leach, Jennie B.Carrier, Rebecca L.2018-12-172018-12-172013-04-21Lin Wang, Miguel A. Acosta, Jennie B. Leach and Rebecca L. Carrier, Spatially monitoring oxygen level in 3D microfabricated cell culture systems using optical oxygen sensing beads , Lab Chip. 2013 Apr 21; 13(8): 1586–1592. doi: 10.1039/c3lc41366g10.1039/c3lc41366ghttp://hdl.handle.net/11603/12287Capability of measuring and monitoring local oxygen concentration at the single cell level (tens of microns scale) is often desirable but difficult to achieve in cell culture. In this study, biocompatible oxygen sensing beads were prepared and tested for their potential for real-time monitoring and mapping of local oxygen concentration in 3D micro-patterned cell culture systems. Each oxygen sensing bead is composed of a silica core loaded with both an oxygen sensitive Ru(Ph₂phen₃)Cl₂ dye and oxygen insensitive Nile blue reference dye, and a poly-dimethylsiloxane (PDMS) shell rendering biocompatibility. Human intestinal epithelial Caco-2 cells were cultivated on a series of PDMS and type I collagen based substrates patterned with micro-well arrays for 3 or 7 days, and then brought into contact with oxygen sensing beads. Using an image analysis algorithm to convert florescence intensity of beads to partial oxygen pressure in the culture system, tens of microns-size oxygen sensing beads enabled the spatial measurement of local oxygen concentration in the microfabricated system. Results generally indicated lower oxygen level inside wells than on top of wells, and local oxygen level dependence on structural features of cell culture surfaces. Interestingly, chemical composition of cell culture substrates also appeared to affect oxygen level, with type-I collagen based cell culture systems having lower oxygen concentration compared to PDMS based cell culture systems. In general, results suggest that oxygen sensing beads can be utilized to achieve real-time and local monitoring of microenvironment oxygen level in 3D microfabricated cell culture systems.13 pagesen-USThis 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.spatially monitoring3D microfabricated celloptical oxygensensing beadsan image analysis algorithm to convert florescence intensity of beads to partial oxygen pressureText