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- Eleftheriou, Nikolas, et al.
(författare)
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Entrapment of Living Bacterial Cells in Low-Concentration Silica Materials Preserves Cell Division and Promoter Regulation
- 2013
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Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 25:23, s. 4798-4805
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Tidskriftsartikel (refereegranskat)abstract
- The entrapment of bacterial cells within inorganic silica materials was reported almost 20 years ago. However, almost all studies to date have shown that these entrapped cells are unable to divide and thus should be expected to have reduced promoter activity. In view of the importance of bacteria as model systems for both fundamental and applied biological studies, it is crucial that immobilized cells retain solutionlike properties, including the ability to divide and display normal promoter activity. Herein we report on a method to immobilize bacterial cells within low-density inorganic silica-based materials, where the cells retain both cell division and promoter activity. Sol gel processing was used to entrap Escherichia coli cells carrying a variety of green fluorescent protein-linked promoters into sodium silicate-derived materials that were formed in microwell plates. Using a series of assays, we were able to demonstrate that (1) the entrapped cells can divide within the pores of the silica matrix, (2) cellular pathways are regulated in a similar manner in both solution and the sol-gel-derived materials, and (3) promoters in entrapped cells can be specifically induced with small molecules (e.g., antimicrobial compounds) in a concentration-dependent manner to allow assessment of both potency and mode of action. This solid-phase assay system was tested using multiple antimicrobial pathways and should enable the development of solid-phase assays for the discovery of new small molecules that are active against bacteria.
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| 2. |
- Ge, Xin, et al.
(författare)
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Sol-Gel-Derived Materials for Production of Pin-Printed Reporter Gene Living-Cell Microarrays
- 2013
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 1520-6882 .- 0003-2700. ; 85:24, s. 12108-12117
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Tidskriftsartikel (refereegranskat)abstract
- We report the fabrication of three-dimensional living-cell microarrays via pin-printing of soft sol-gel-derived silica materials containing bacterial cells. Bacterial cells entrapped in the silica-glycerol microarray spots can express reporter genes and produce strong fluorescence signals. The signals responded to the presence and concentration of inducers or repressors as expected, indicating that the entrapped cells remained metabolically active. Microscopic imaging of individual microarray spots at different culture times suggests that the entrapped cells can grow and divide, phenomena further confirmed by experiments in bulk sol-gel materials that demonstrated the increases of entrapped cell density and fluorescence during incubation in culture media. The cell microarrays can also be printed into 96-well glass bottom microtiter plates in a multiplexed manner, and the fluorescence signals generated were able to quantitatively and selectively respond to the concentration of inducers, thus demonstrating the potential for multitarget biosensing and high-throughput/high-content cell-based screening. The signal levels of bacterial cells in silica were significantly higher than those in alginate arrays, presumably due to viability of the entrapped cells in silica sol-gels. Microarray stability assays proved that the entrapped cells retained their physiological activity after storage for four weeks. Given that a large number of fluorescent and luminescent protein-based cell assays have been developed, the reporter gene living-cell microarrays demonstrated in this paper are expected to be applicable to a wide variety of research areas ranging from bioanalysis and chemical biology to drug discovery and probing of cell-material interactions.
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