Fig. 4.

Bioluminescent response of NanoLuc protein expressed in CFPS reactions on paper substrate. 12 μL CFPS reagents were air-dried on blotting paper with the indicated amount of NanoLuc substrate. “(-)” indicates negative DNA template control. Reactions were rehydrated with 12 μL water and response was monitored over the course of 30 min. Bioluminescent response was photographed at regular intervals in a dark room with a camera shutter speed of 2 s and high ISO, which resulted in signal detection sensitivity only slightly higher than that of the naked eye of two observers. Reaction in which no substrate was added prior to rehydration had substrate added 20 min after reaction was initiated.