Targeted photopolymerization is the basis for multiple diagnostic and cell encapsulation technologies. While eosin is used in conjunction with tertiary amines as a water-soluble photoinitiation system, eosin is not widely sold as a conjugate with antibodies and other targeting biomolecules. Here we evaluate the utility of fluorescein-labeled bioconjugates to photopolymerize targeted coatings on live cells. We show that although fluorescein conjugates absorb approximately 50% less light energy than eosin in matched photopolymerization experiments using a 530 nm LED lamp, appreciable polymer thicknesses can still be formed in cell compatible environments with fluorescein photosensitization. At low photoinitiator density, eosin allows more sensitive initiation of gelation. However at higher functionalization densities, the thickness of fluorescein polymer films begins to rival that of eosin. Commercial fluorescein-conjugated antibodies are also capable of generating conformal, protective coatings on mammalian cells with similar viability and encapsulation efficiency as eosin systems.
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This work was partially supported by R01 HL127682-01 and the National Science Foundation under Award CBET-1351531 to Brad Berron. The authors acknowledge the financial support from the National Cancer Institute (NCI) Grant R25CA153954 and a National Cancer Institute Cancer Nanotechnology Training Center (NCI-CNTC) Traineeship.
Lilly, Jacob L.; Gottipati, Anuhya; Cahall, Calvin F.; Agoub, Mohamed; and Berron, Brad J., "Comparison of Eosin and Fluorescein Conjugates for the Photoinitiation of Cell-Compatible Polymer Coatings" (2018). Chemical and Materials Engineering Faculty Publications. 51.
Plot of concentration vs. UV-vis spectral absorbance at 280 nm of streptavidin prepared in PBS 1X used to prepare standard curve by linear regression. https://doi.org/10.1371/journal.pone.0190880.s001
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Plot of concentration vs. UV-vis spectral absorbance at 530 nm of eosin-isothiocyanate prepared in PBS 1X used to prepare standard curve by linear regression. https://doi.org/10.1371/journal.pone.0190880.s002
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Plot of concentration vs. UV-Vis spectral absorbance at 495 nm of fluorescein-isothiocyanate prepared in PBS 1X used to prepare standard curve by linear regression. https://doi.org/10.1371/journal.pone.0190880.s003
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Plot of concentration vs. UV-Vis spectral absorbance at 550 nm of Cy3 prepared in PBS 1X used to prepare standard curve by linear regression. https://doi.org/10.1371/journal.pone.0190880.s004
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Calibration of Cy3 fluor per μm2 vs. scanner signal intensity for Cy3 microarray calibration slide (Full Moon BioSystems). https://doi.org/10.1371/journal.pone.0190880.s005
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Individual data points in an .xlsx file for Figs 3 and 4. https://doi.org/10.1371/journal.pone.0190880.s006
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Individual data points in an .xlsx format for Fig 5. https://doi.org/10.1371/journal.pone.0190880.s007
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Individual data points in an .xlsx format for S1 Fig, S2 Fig, S3 Fig, S4 Fig, and S5 Fig. https://doi.org/10.1371/journal.pone.0190880.s008