Fig. 1

Preparation of cellulose-based ratiometric fluorescent materials. a Synthetic routes of CA-FITC and CA-PpIX. b Cellulose-based dual-emission solid fluorescent materials with different mix ratio of CA-PpIX to CA-FITC (w/w), namely 1:0, 5:1, 3:1, 2.5:1, 1.5:1, 1:1, 1:2, 1:3, 0:1, respectively, under 365 nm UV light