Standoff Optical Glucose Sensing in Photosynthetic Organisms by a Quantum Dot Fluorescent Probe

Abstract

Glucose is a major product of photosynthesis and a key energy source for cellular respiration in organisms. Herein, we enable in vivo optical glucose sensing in wild-type plants using a quantum dot (QD) ratiometric approach. The optical probe is formed by a pair of QDs: thioglycolic acid-capped QDs which remain invariable to glucose (acting as an internal fluorescent reference control) and boronic acid (BA)-conjugated QDs (BA-QD) that quench their fluorescence in response to glucose. The fluorescence response of the QD probe is within the visible light window where photosynthetic tissues have a relatively low background. It is highly selective against other common sugars found in plants and can be used to quantify glucose levels above 500 μM in planta within the physiological range. We demonstrate that the QD fluorescent probe reports glucose from single chloroplast to algae cells ( Chara zeylanica) and plant leaf tissues ( Arabidopsis thaliana) in vivo via confocal microscopy and to a standoff Raspberry Pi camera setup. QD-based probes exhibit bright fluorescence, no photobleaching, tunable emission peak, and a size under plant cell wall porosity offering great potential for selective in vivo monitoring of glucose in photosynthetic organisms in situ.

Facile Non-Enzymatic Electrochemical Sensing for Glucose Based on Cu2O–BSA Nanoparticles Modified GCE

“…Many methods have been used for glucose sensing, including electrochemical [2,3,4,5,6,7,8,9,10], chemiluminescence [11,12,13], colorimetry [2,14], Raman spectra [15,16], and fluorescence spectrometry [17,18,19,20,21]. In these methods, electrochemical glucose sensors are very important, because this method is simple and selective, along with having low detection limit, fast response time, good stability and low cost [2,3,4,5,6,7,8,9,10].…”

Targeted delivery of nanomaterials with chemical cargoes in plants enabled by a biorecognition motif

“…The β-CD molecular basket composed of seven cyclic oligosaccharides enables "hostguest" formation with ascorbic acid or methyl viologen 36,37 and can form inclusion complexes with a broad range of biomolecules 12,17,38,39 . Furthermore, QD have a high and stable fluorescence enabling in vivo tracking within plant tissues and cellular compartments 40 . The Chl-QD fluorescence peak was tuned to 540 nm to reduce interference with leaf background and fluorescent dyes used in this study (Fig.…”

“…All confocal microscopy images were analyzed using FIJI (ImageJ) in which QD, DHE, and chloroplast images were evenly divided by drawing six lines of the region of interest (ROI), with the same length and distance between each ROI line 26,40 . The corresponding fluorescence intensity profiles of QD and DHE fluorescence and chloroplast autofluorescence were then measured across the six ROI line sections and reported as a subset of the image showing signal intensity plot.…”

The Emergence of Plant Nanobionics and Living Plants as Technology

“…Although the target analyte was exogenously introduced, the demonstration showcased the potential of engineered nanoparticles as sensitive and versatile optical probes for the detection of short‐lived molecules in planta. Besides SWNT‐based nanosensors, Li et al used quantum dots probes to monitor glucose in plants that was exogenously supplied . The principle of operation relies on fluorescent quenching upon glucose binding to boronic acid‐conjugated quantum dots.…”

“…Besides SWNT-based nanosensors, Li et al used quantum dots probes to monitor glucose in plants that was exogenously supplied. [30] The principle of operation relies on fluorescent quenching upon glucose binding to boronic acid-conjugated quantum dots. Glucose determines growth and developmental processes in plants, being a key signaling molecule.…”