Bacterial Sunscreen: Layer-by-Layer Deposition of UV-Absorbing Polymers on Whole-Cell Biosensors

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• 作者：D. Matthew Eby ; Svetlana Harbaugh ; Randi N. Tatum ; Karen E. Farrington ; Nancy Kelley-Loughnane ; Glenn R. Johnson
• 刊名：Langmuir
• 出版年：2012
• 出版时间：July 17, 2012
• 年：2012
• 卷：28
• 期：28
• 页码：10521-10527
• 全文大小：357K
• 年卷期：v.28,no.28(July 17, 2012)
• ISSN：1520-5827

文摘

UV-protective coatings on live bacterial cells were created from the assembly of cationic and UV-absorbing anionic polyelectrolytes using layer-by-layer (LbL) methodology. A cationic polymer (polyallylamine) and three different anionic polymers with varying absorbance in the UV range (poly(vinyl sulfate), poly(4-styrenesulfonic acid), and humic acid) were used to encapsulate Escherichia coli cells with two different green fluorescent protein (GFP) expression systems: constitutive expression of a UV-excitable GFP (GFPuv) and regulated expression of the intensely fluorescent GFP from amphioxus (GFPa1) through a theophylline-inducible riboswitch. Riboswitches activate protein expression after specific ligand鈥揜NA binding events. Hence, they operate as a cellular biosensor that will activate reporter protein synthesis after exposure to a ligand target. E. coli cells coated with UV-absorbing polymers demonstrated enhanced protection of GFP stability, metabolic activity, and viability after prolonged exposure to radiation from a germicidal lamp. The results show the effectiveness of LbL coatings to provide UV protection to living cells for biotechnological applications.