Efficient Two-Photon Luminescence for Bioimaging Using Polymer Conjugations of Graphene Quantum Dots Based Materials

In this study, examination results revealed that conjugated polymers containing nitrogen and sulfur atoms lead to a higher quantum confinement of emissive energy trapped on the surface of material (graphene quantum dot (GQD)-polymers), resulting in a high luminescence quantum yield and impressive two-photon properties. Additionally, the GQD-polymers generated nonreactive oxygen species-dependent oxidative stress on cells. Furthermore, we demonstrated the effective use of two-photon excitation-mediated high two-photon luminescence intensity in an acidic environment enableed GQD-polymers to act as a promising contrast probe. When cancer cells are labeled with specific antibody GQD-polymers conjugates, molecular-specific imaging can be performed deep into a tissue phantom with extremely high signal-to-noise ratios. In situations in which imaging depths are limited by the maximum available power that can be delivered to the three-dimensional (3D) bioimaging plane without causing damage to tissue, GQD-polymers might provide sufficient brightness to extend the maximum depth of imaging. Moreover, we demonstrated that the use of GQD-polymers can expand the capabilities of two-photon imaging to allow noninvasive 3D bioimaging of a variety of new molecular signatures.