Graphene quantum dots (GQDs) have various alluring properties and potential applications, but their large-scale applications are limited by current synthetic methods that commonly produce GQDs in small amounts. Moreover, GQDs usually exhibit polycrystalline or highly defective structures and thus poor optical properties. Here we report the gram-scale synthesis of single-crystalline GQDs by a facile molecular fusion route under mild and green hydrothermal conditions. The synthesis involves the nitration of pyrene followed by hydrothermal treatment in alkaline aqueous solutions, where alkaline species play a crucial role in tuning their size, functionalization and optical properties. The single-crystalline GQDs are bestowed with excellent optical properties such as bright excitonic fluorescence, strong excitonic absorption bands extending to the visible region, large molar extinction coefficients and long-term photostability. These high-quality GQDs can find a large array of novel applications in bioimaging, biosensing, light emitting diodes, solar cells, hydrogen production, fuel cells and supercapacitors.

River Scholar of China and the Foreign Academicians of the Russian Academy of Engineering and Russian Academy of Science. Her research interests mainly focus on bioeffects and safety evaluation of nanomaterials and environmental pollution analysis and control. Rui L. Reis obtained his Ph.D. and D.Sc. in polymer engineering-biomaterials & tissue engineering from the University of Minho, Portugal. He is vice president for Research and Innovation of UMinho and the director of the 3B's Research Group and ICVS/3B's Associate Laboratory. He is a full professor of Tissue Engineering, Regenerative Medicine and Stem Cells at UMinho and honorary professor in four different Asian Universities. His main area of research is the development of biomaterials from natural origin polymers, and using those in combination with different stem cells for several strategies for tissue engineering and regenerative medicine, applied to distinct human tissues.

Size, shape, and protein corona play a key role in cellular uptake and removal mechanisms of gold nanoparticles (Au NPs). The 15 nm nanoparticles (NP1), the 45 nm nanoparticles (NP2), and the rod‐shaped nanoparticles (NR) enter into cells via a receptor‐mediated endocytosis (RME) pathway. The star‐shaped nanoparticles (NS) adopt not only clathrin‐mediated, but also caveolin‐mediated endocytosis pathways. However, the 80 nm nanoparitcles (NP3) mainly enter into the cells by macropinocytosis pathway due to the big size. Furthermore, the results indicate that the presence of protein corona can change the uptake mechanisms of Au NPs. The endocytosis pathway of NP1, NP2, and NS changes from RME to macropinocytosis pathway and NR changes from RME to clathrin and caveolin‐independent pathway under the non‐fetal bovine serun (FBS)‐coated condition. Both FBS‐coated and non‐FBS‐coated of five types of Au NPs are released out through the lysosomal exocytosis pathway. The size, shape, and protein corona have an effect on the exocytosis ratio and amount, but do not change the exocytosis mechanism. The systematic study of the endocytosis and exocytosis mechanism of Au NPs with different sizes and shapes will benefit the toxicology evaluation and nanomedicine application of Au NPs.