Joint Fall 2021 Meeting of the Texas Sections of APS, AAPT, and SPS
Volume 66, Number 10
Thursday–Saturday, October 21–23, 2021;
Houston; Central Time
Session J03: Biological Physics and Medical Physics I
10:00 AM–12:00 PM,
Friday, October 22, 2021
Room: STEM 1200
Chair: Paul Withey, UHCL
Abstract: J03.00001 : Biomedical Imaging with Biocompatible Graphene Quantum Dots*
10:00 AM–10:36 AM
Preview Abstract
Abstract
Author:
ANTON NAUMOV
(Texas Christian University)
Due to a variety of their remarkable properties, nanomaterials serve a
plethora of applications in biomedicine including molecular sensing, drug
and gene delivery as well as photothermal and photodynamic therapy. Most of
these applications can benefit from additional modality of biomedical
imaging that is often performed by a dye attached to the nanomaterial.
Nanomaterial imaging agents are more rare due to the need of high quantum
yields and low toxicity at high concentrations which are complex to achieve
for nanostructures. In this work we utilize simple scalable one-step
hydrothermal synthesis to develop graphene quantum dots (GQDs) with high
biocompatibility (up to 2 mg/mL) and substantial (over 60{\%}) fluorescence
quantum yield in the visible. These GQDs show efficient cellular
internalization maximized at 12 h as well as remarkable biodegradability in
cell medium. Furthermore, their backbone can be doped with a variety of
heteroatoms during the synthetic process with minimum effect to their
biocompatibility. Such doping can serve to develop a number of beneficial
biomedical imaging applications. For instance, Gd or Mn doping can generate
magnetic resonance imaging capabilities allowing to perform joint
fluorescence and MR imaging for in vitro and in vivo detection respectively.
Nitrogen doping renders GQD fluorescence linearly sensitive to temperature
in the biological range allowing those to serve in nanothermometry imaging
applications. Rare earth metal doping makes these GQDs emissive in the
near-infrared (NIR), which is beneficial for therapeutic imaging in the NIR
water window, where biological tissue is more transparent. Several
NIR-emissive GQD structures are tested in our work for imaging in vitro as
well as in live sedated animals. Due to high NIR penetration depth, GQD
fluorescence was observed through the bodies of live mice injected
intravenously with GQD suspensions and imaged with diffuse 808 nm laser
excitation. Excised organs show NIR GQD emission from kidneys, liver, spleen
and intestine with GQDs also detected in single organ slices indicating
their location within the particular organ. Based on the variety of observed
imaging modalities, we suggest these biocompatible GQDs as a novel
modifiable imaging platform that can be further doped and tailored for
specific bioapplications.
*Authors Acknowledge NIH R15 grant #EB031528-01