Photoluminescence Response in Carbon Nanomaterials to Enzymatic Degradation

• Published in: Analytical chemistry (Washington) Vol. 92; no. 19; pp. 12880 - 12890
• Main Authors: He, Xiaoyun, White, David L, Kapralov, Alexandr A, Kagan, Valerian E, Star, Alexander
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 06.10.2020
• Subjects: Biocatalysis; Biodegradation; Carbon; Carboxymethylcellulose; Chemistry; Fluorescence; Graphene; Graphite - chemistry; Graphite - metabolism; HL-60 Cells; Humans; Hydrogen peroxide; Leukocytes (neutrophilic); Luminescence; Nanomaterials; Nanotechnology; Nanotubes; Nanotubes, Carbon - chemistry; Oxidation; Peroxidase; Peroxidase - chemistry; Peroxidase - metabolism; Photochemical Processes; Photoluminescence; Photons; Quantum dots; Sensors; Single wall carbon nanotubes; Sodium cholate; Surfactants
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/acs.analchem.0c01380

Myeloperoxidase (MPO), a key enzyme released by neutrophils during inflammation, has been shown to catalyze the biodegradation of carbon nanomaterials. In this work, we perform photoluminescence studies on the MPO-catalyzed oxidation of graphene oxide (GO) and surfactant-coated pristine (6,5) single-walled carbon nanotubes (SWCNTs). The enzymatic degradation mechanism involves the introduction of defects, which promotes further degradation. Interestingly, the photoluminescence responses of GO and SWCNTs to enzymatic degradation are counterposed. Although the near-infrared (NIR) fluorescence intensity of SWCNTs at 998 nm is either unchanged or decreases depending on the surfactant identity, the blue fluorescence intensity of GO at 440 nm increases with the progression of oxidation by MPO/H2O2/Cl– due to the formation of graphene quantum dots (GQDs). Turn-on GO fluorescence is also observed with neutrophil-like HL-60 cells, indicative of potential applications of GO for imaging MPO activity in live cells. Based on these results, we further construct two ratiometric sensors using SWCNT/GO nanoscrolls by incorporating surfactant-wrapped pristine SWCNTs as the internal either turn-off (with sodium cholate (SC)) or reference (with carboxymethylcellulose (CMC)) sensor. The ratiometric approach enables the sensors to be more stable to external noise by providing response invariant to the absolute intensity emitted from the sensors. Our sensors show linear response to MPO oxidative machinery and hold the promise to be used as self-calibrating carbon nanomaterial-based MPO activity indicators.