Monitoring Plant Health with Near-Infrared Fluorescent H₂O₂ Nanosensors

Abstract

Near-infrared (nIR) fluorescent single-walled carbon nanotubes (SWCNTs) were designed and interfaced with leaves of Arabidopsis thaliana plants to report hydrogen peroxide (H2O2), a key signaling molecule associated with the onset of plant stress. The sensor nIR fluorescence response (>900 nm) is quenched by H2O2 with selectivity against other stress-associated signaling molecules and within the plant physiological range (10–100 H2O2 μM). In vivo remote nIR imaging of H2O2 sensors enabled optical monitoring of plant health in response to stresses including UV-B light (−11%), high light (−6%), and a pathogen-related peptide (flg22) (−10%), but not mechanical leaf wounding (<3%). The sensor’s high biocompatibility was reflected on similar leaf cell death (<5%) and photosynthetic rates to controls without SWCNT. These optical nanosensors report early signs of stress and will improve our understanding of plant stress communication, provide novel tools for precision agriculture, and optimize the use of agrochemicals in the environment.

Transport and programmed release of nanoscale cargo from cells by using NETosis

“…56 As a second functional nanomaterial, we employed hemin-aptamer-functionalized SWCNTs, 57,58 which are known to decrease their fluorescence in the presence of H 2 O 2 . [57][58][59] In both cases, SWCNTs were taken up by neutrophils and their responses were measured via consecutive nIR imaging either while they were carried by non-activated cells or after NETotic membrane rupture. Here, the addition of 100 nM dopamine led to an instantaneous increase of the sensors' intensity for disrupted cells.…”

“…The sequence of the hemin-binding aptamer was (5′-AGT GTG AAA TAT CTA AAC TAA ATG TGG AGG GTG GGA CGG GAA GAA GTT TAT TTT TCA CAC T-3′). 57,59…”

Quantendefekte als Werkzeugkasten für die kovalente Funktionalisierung von Kohlenstoffnanoröhren mit Peptiden und Proteinen

“…[5] Folglich fanden SWCNTs bereits Anwendung in verschiedenen Bereichen, die von der In-vivo-NIR-Bildgebung [6][7][8] über die gesteuerte Wirkstofffreisetzung [9,10] bis hin zu optischen NIR-Sensoren reichen. [11][12][13][14][15][16][17][18][19][20] Um ihre gewünschte Funktion in diesen wichtigen Anwendungen erfüllen zu kçnnen, muss die Kohlenstoffnanorçhre z. B. mit der zu transportierenden Fracht oder einer Erkennungseinheit modifiziert werden, die eine Spezifitätfürden zu detektierenden Analyten vermittelt.…”

Quantum Defects as a Toolbox for the Covalent Functionalization of Carbon Nanotubes with Peptides and Proteins

“…[5] Consequently,SWCNTs already found application in diverse settings ranging from in vivo NIR imaging [6][7][8] over drug delivery vehicles [9,10] to NIR optical sensors. [11][12][13][14][15][16][17][18][19][20] In order to carry out their desired function in these important applica-tions,t he pure carbon tube has to be modified with, for example,t he cargo to be carried or ar ecognition unit imparting specificity for the analyte to be detected. Furthermore,c arbon nanotubes are not water-soluble,p reventing applications in aqueous systems unless the hydrophobic surface is coated with an amphiphilic surfactant.…”