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. 2021 Feb 1;12:724. doi: 10.1038/s41467-020-20639-6

Fig. 1. Development of a glucose meter interface for cell-free, gene circuit-based sensors.

Fig. 1

a Concept schematic of glucose generation by reporter enzymes upon the activation of gene circuit sensors. b Expression of different reporter enzymes can be used to generate glucose using their respective substrates. c Using a glucose meter for measurement, glucose is generated from the expression of three enzymes: trehalase (Tre), lactase (Lac), phosphatase (Phos). 5 ng/µL plasmid DNA used for expression, reactions incubated for 16 h. Control reactions (-) were identical, but lacked DNA encoding an enzyme. d Cell-free protein expression reactions were also analyzed for glucose production using a colorimetric GDH-NAD absorbance-based assay. e Using the expression of GDH and a titration of NAD concentration, glucose can be selectively removed from samples. Negative controls (−), without GDH and/or NAD, show no background glucose degradation. GDH DNA added to 10 ng/µL. All data presented are the mean of N = 3 independent experiments (as indicated by dot plots) ±SD. Statistical analysis: one-way ANOVA, ns = not significant. Source data are provided as a Source Data file.