Project Summary/Abstract
Near-infrared (NIR) imaging is one of the most rapidly developing perspective techniques in
biomedical diagnostics enabling 10 - 100 times deeper tissue imaging than regular visible
fluorescence techniques. There is a significant clinical need for such imaging: high-depth CT and
MRI imaging strategies are complex and less suitable for low-depth biosensing and intraoperative
applications. Furthermore, in animal studies NIR imaging can enable in situ fluorescence tracking
of tested therapeutics or tumor visualization inside a living small animal. However, as NIR imaging
field is still developing, there is a lack of biocompatible and multifunctional platforms suitable for
imaging, sensing and even drug transport highly desired in animal studies.
In this project we will develop and test the feasibility of a novel NIR imaging platform based on
graphene quantum dots (GQDs) addressing the critical needs of NIR bioimaging: fluorescence in
the NIR (above 950 nm) with NIR excitation, high biocompatibility, photostability, and capabilities
for drug tracing and in vivo NIR imaging in live animal models. This will be implemented in 3 steps:
(1) synthesizing NIR-emissive GQDs via bottom-up and top-down approaches and characterizing
their optical and physical properties, (2) testing GQDs for NIR in vitro imaging and assessing their
biocompatibility and (3) performing in vivo imaging of GQD NIR fluorescence in live animals as well
as ex vivo organ tissue imaging quantifying GQD content in excised organs. We will concomitantly
assess potential adverse effects to select non-toxic GQD candidates. Throughout this process a variety
of synthesized GQD structures will undergo rigorous 3-step selection for the capabilities of (1) high
yield NIR fluorescence, (2) high biocompatibility and NIR imaging in cells, (3) NIR imaging inside a live
sedated animal with minimal/no toxicity. The selected GQD candidates will enable in vivo animal
testing of therapeutic delivery with noninvasive real-time image tracking reducing the number of
animals sacrificed. In a longer term, we expect these GQD platforms to become a basis of the
noninvasive NIR in vivo sensing in patients. As a result, the proposed initiative will address several
significant areas of biotechnology and its development will ultimately contribute to the
improvement of human health.