Next Article in Journal
Corrosion Inhibitor-Modified Plasma Electrolytic Oxidation Coatings on 6061 Aluminum Alloy
Next Article in Special Issue
Endogenous H2O2-Sensitive and Weak Acidic pH-Triggered Nitrogen-Doped Graphene Nanoparticles (N-GNMs) in the Tumor Microenvironment Serve as Peroxidase-Mimicking Nanozymes for Tumor-Specific Treatment
Previous Article in Journal
In Vitro Comparison between Metal Sleeve-Free and Metal Sleeve-Incorporated 3D-Printed Computer-Assisted Implant Surgical Guides

Graphene Quantum Dots as Intracellular Imaging-Based Temperature Sensors

Department of Physics and Astronomy, Texas Christian University, Fort Worth, TX 76129, USA
Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
Author to whom correspondence should be addressed.
Academic Editor: Anton Naumov
Materials 2021, 14(3), 616;
Received: 18 December 2020 / Revised: 23 January 2021 / Accepted: 26 January 2021 / Published: 29 January 2021
(This article belongs to the Special Issue Bio-Nanomaterials)
Non-invasive temperature sensing is necessary to analyze biological processes occurring in the human body, including cellular enzyme activity, protein expression, and ion regulation. To probe temperature-sensitive processes at the nanoscale, novel luminescence nanothermometers are developed based on graphene quantum dots (GQDs) synthesized via top-down (RGQDs) and bottom-up (N-GQDs) approaches from reduced graphene oxide and glucosamine precursors, respectively. Because of their small 3–6 nm size, non-invasive optical sensitivity to temperature change, and high biocompatibility, GQDs enable biologically safe sub-cellular resolution sensing. Both GQD types exhibit temperature-sensitive yet photostable fluorescence in the visible and near-infrared for RGQDs, utilized as a sensing mechanism in this work. Distinctive linear and reversible fluorescence quenching by up to 19.3% is observed for the visible and near-infrared GQD emission in aqueous suspension from 25 °C to 49 °C. A more pronounced trend is observed with GQD nanothermometers internalized into the cytoplasm of HeLa cells as they are tested in vitro from 25 °C to 45 °C with over 40% quenching response. Our findings suggest that the temperature-dependent fluorescence quenching of bottom-up and top-down-synthesized GQDs studied in this work can serve as non-invasive reversible/photostable deterministic mechanisms for temperature sensing in microscopic sub-cellular biological environments. View Full-Text
Keywords: graphene quantum dots; nanothermometry; fluorescence; in vitro; temperature sensing graphene quantum dots; nanothermometry; fluorescence; in vitro; temperature sensing
Show Figures

Graphical abstract

MDPI and ACS Style

Lee, B.H.; McKinney, R.L.; Hasan, M.T.; Naumov, A.V. Graphene Quantum Dots as Intracellular Imaging-Based Temperature Sensors. Materials 2021, 14, 616.

AMA Style

Lee BH, McKinney RL, Hasan MT, Naumov AV. Graphene Quantum Dots as Intracellular Imaging-Based Temperature Sensors. Materials. 2021; 14(3):616.

Chicago/Turabian Style

Lee, Bong H., Ryan L. McKinney, Md. T. Hasan, and Anton V. Naumov 2021. "Graphene Quantum Dots as Intracellular Imaging-Based Temperature Sensors" Materials 14, no. 3: 616.

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

Back to TopTop