A near-infrared optical nanosensor for measuring aerobic respiration in microbial systems

Abstract

We developed a ratiometric optical oxygen nanosensor using a near-infrared oxygen indicator and a stable reference dye. We demonstrated its applicability through a microwell plate assay in which we observed oxygen consumption in brewing yeast.

Sensors in a Flash! Oxygen Nanosensors for Microbial Metabolic Monitoring Synthesized by Flash Nanoprecipitation

“…Variations between the two oxygen consumption curves in Figure 5 match previous oxygen consumption trends between the two yeast strains as previously observed. 21 Thus, the nanosensors can continuously monitor oxygen consumption with adequate reversibility capabilities.…”

“…The nanosensors were also tested to monitor oxygen consumption in Saccharomyces cerevisiae fermentations with potassium metabisulfite (PMB) as an antimicrobial agent to halt metabolic activityan approach described by Saccomano et al As seen in Figure , once PMB is added 42 h after yeast incubation, a noticeable decline in the ratiometric signal is observed with both yeast strains, though the Kolsch strain showed a more dramatic initial drop post-PMB addition. The decrease in ratiometric signal indicates a decrease in yeast oxygen consumption and an increase in ambient oxygen concentration indicating the efficacy of the antimicrobial agent as expected.…”

“…Oxygen sensing was used for testing, as it has been well characterized with other nanosensor formulation methods, and it has applications in tracking metabolic activity from various organisms, including P. aeruginosa and S. cerevisiae (brewing yeast). 16 , 21 , 40 Because FNP has applications in scalable manufacturing, FNP can be used to improve the scalability and replicability of nanosensors for more widespread diagnostic and exploratory applications.…”

“…For more detail on ratiometric approaches, please see Doussineau et al The incorporation of these sensing components into a polymeric matrix creates what we call a nanosensor. The ratio of these two dyes remains fixed once encapsulated, which enables analyte measurements in complex biological systems by adjusting for nanoparticle concentration. ,, Nanosensors have been developed for a variety of biologically relevant parameters such as pH, electrolytes, glucose, heavy metal ions, and pesticides . A wide variety of analyte nanosensors can be made by simply changing sensing components while tuning the formulation for the concentration range of interest.…”

Development of optical chemosensors based on photochromic polymer nanocarriers

“…A wide range of photochromic compounds including spiropyran, 10,11 spiroxazine, 12 azobenzene, 13 fulgide, 14 naphthopyran, 15 oxazine 16,17 and diarylethene 18 were used in different applications, such as chemosensors, 19,20 anticounterfeiting systems, [21][22][23] drug delivery, 24 data storage, 25 biological sensors 26,27 and bioimaging. 28,29 These organic chromophores are mostly insoluble in aqueous media and also very sensitive toward environmental degradation. Polymeric carriers play a very important role in the preservation of photochromic properties from environmental destruction.…”