Nitrogen and boron dual-doped graphene quantum dots for near-infrared second window imaging and photothermal therapy

Abstract

Fluorescence imaging of biological systems in the second near-infrared window (NIR-II) has recently drawn much attention because of its negligible background noise of autofluorescence and low tissue scattering. Here we present a new NIR-II fluorescent agent, graphene quantum dots dual-doped with both nitrogen and boron (N-B-GQDs). N-B-GQDs have an ultra-small size (~ 5 nm), are highly stable in serum, and demonstrate a peak fluorescent emission at 1000 nm and high photostability. In addition to the NIR-II imaging capability, N-B-GQDs efficiently absorb and convert NIR light into heat when irradiated by an external NIR source, demonstrating a photothermal therapeutic effect that kills cancer cells in vitro and completely suppresses tumor growth in a glioma xenograft mouse model. N-B-GQDs demonstrate a safe profile, prolonged blood half-life, and rapid excretion in mice, which are the characteristics favorable for in vivo biomedical applications.

Enhanced Chemotherapy for Glioblastoma Multiforme Mediated by Functionalized Graphene Quantum Dots

“…Previous studies pointed out the reduced tumorigenicity associated with DMF. Therefore, the functionalization of GQDs with DMF may be of interest for potential biomedical applications in cancer research [28]. Furthermore, the coadministration of GQDs and doxorubicin (Dox) is investigated.…”

Advances in fluorescent carbon dots for biomedical applications

“…The as-prepared B-N-CDs showed a photothermal efficiency of 32.3%, which is lower than that of the red emissive dots of Sun and coworkers [8], but these CDs were slightly more cytotoxic for SF-763 cells. In fact, SF-763 cells treated with B-N-CDs at 100 μg/mL for 2 h, showed 96% mortality when irradiated with NIR light (808 nm, 1.5 W/cm 2 ) for 5 min [97]. Astonishingly, non-irradiated cells treated with B-N-CDs displayed viability of 90%.…”

“…demonstrated near infrared-emissive CDs with a peak at 1000 nm. These CDs were doped with nitrogen and boron in order to achieve long wavelength emission and induce higher tissue penetration [97]. The as-prepared B-N-CDs showed a photothermal efficiency of 32.3%, which is lower than that of the red emissive dots of Sun and coworkers [8], but these CDs were slightly more cytotoxic for SF-763 cells.…”

“…The authors tested these Ce6-CDs on three cancer lines (4T1, HepG2, HeLa) and found no cytotoxic effects, while upon laser irradiation (671 nm, 500 mW cm −2 ) for 20 min at a concentration of 200 μg/ml the mortality rate varied between 80 and 90% for the different cancer lines [99]. Despite the fact that the mortality rate is not the highest found in the literature [97], the authors managed to induce high mortality rates in cancer cells by using low irradiation power and a small amount of Ce6 [99]. These results indicate that not only the Ce6-CDs can be employed for in vivo studies, but also for clinical applications since they treat the tumor area in a more effective and precise way than other already reviewed studies.…”

Graphene Quantum Dots for Optical Bioimaging

“…It could simultaneously produce NIR fluorescence and use as photoacoustic imaging in tumor diagnosis with advanced PTT effect. Recently, wang et al also successfully applied nitrogen‐ and boron‐doped GQDs (N‐B‐GQDs) for near‐infrared second window imaging and photothermal therapy …”