Fig. 3: NIR fluorescent sensor hydrogels.
From: Remote near infrared identification of pathogens with multiplexed nanosensors
a NIR image of a polyethylene glycol hydrogel (PEG-HG) with embedded/copolymerized nanosensors in three identical regions (discs). Images were acquired remotely (distance 25 cm) with an InGaAs camera (see Fig. 4a for a picture of the setup). Here, only sensors reporting protease activity (see panel b) are depicted, but the concept applies to all sensors (scale bar = 0.5 cm). Note that the different NIR intensities of the discs are due to slight differences in illumination/imaging (distance/angle between sample and camera). b Protein (bovine serum albumin, BSA) functionalized SWCNTs, incorporated into a porous PEG-HG, decrease their fluorescence in response to protease from Streptomyces griseus (n = 3 independent experiments with three technical replicates each, mean ± SD) and V8 protease from Staphylococcus aureus (Endoproteinase Glu-C, 13.5 U/mL ~ 18 µg/mL) (n = 3 independent experiments, mean ± SD). c Long, genomic DNA molecules (denatured calf thymus (CT)-DNA) on SWCNTs serve as substrate for nucleases. Incorporated into a porous HG, fluorescence decreases in response to native DNases I or S. aureus nucleases (11 UN/mL ~ 55 µg/mL) (n = 3 independent experiments with three technical replicates each, mean ± SD). d, e Tailored nanosensors (see Fig. 2) are still functional when incorporated into a hydrogel (n = 3 independent experiments with three technical replicates each, mean ± SD). f (GT)10-SWCNTs (as one of the generic DNA/SWCNT sensors) in a HG shows a pH-dependent fluorescence response (evaluated after 24 h) (n = 3 independent experiments with three technical replicates each, mean ± SD).
