iNap sensor for NADPHPre made plasmids expressing iNaps, highly responsive sensors for NADPH. Variants of iNaps have different affinity, enabling them to be used in cells or subceullar organells with various NADPH levels. 1\iNap sensor. The original iNap sensors is excited by 420 and 485 nm and emit green fluorescence. The fluorescence ratio of iNap when excited at 420 and 485 nm reports NADPH redox state. iNaps fluorescence when excited at 485 nm is sensitive to pH,