The emergence of photoluminescent carbon-based nanomaterials has shown exciting potential in the development of benign nanoprobes. However, the in vivo kinetic behaviors of these particles that are necessary for clinical translation are poorly understood to date. In this study, fluorescent carbon dots (C-dots) were synthesized and the effect of three injection routes on their fate in vivo was explored by using both near-infrared fluorescence (NIRF) and positron emission tomography (PET) imaging techniques. We found that C-dots are efficiently and rapidly excreted from the body after all three injection routes. The clearance rate of C-dots is ranked as: intravenous > intramuscular > subcutaneous. The particles had relatively low retention in the reticuloendothelial system (RES) and showed high tumor-to-background contrast. Furthermore, different injection routes also resulted in different blood clearance patterns and tumor uptakes of C-dots. These results satisfy the need for clinical translation and should promote efforts to further investigate the possibility of using carbon-based nanoprobes in a clinical setting. More broadly, we provide a testing blueprint for in vivo behavior of nanoplatforms under various injection routes, an important step forward towards safety and efficacy analysis of nanoparticles.

Various approaches to improve the efficiency of solar cells have followed the integration of nanomaterials into Si-based photovoltaic devices. Here, we achieve 13.8% efficiency solar cells by combining carbon nanotubes and Si and doping with dilute HNO(3). Acid infiltration of nanotube networks significantly boost the cell efficiency by reducing the internal resistance that improves fill factor and by forming photoelectrochemical units that enhance charge separation and transport. Compared to conventional Si cells, the fabrication process is greatly simplified, simply involving the transfer of a porous semiconductor-rich nanotube film onto an n-type crystalline Si wafer followed by acid infiltration.

18F-FPPRGD2, which was approved for clinical study recently, has favorable properties for integrin targeting and showed potential for antiangiogenic therapy and early response monitoring. However, the time-consuming multiple-step synthesis may limit its widespread applications in the clinic. In this study, we developed a simple lyophilized kit for labeling PRGD2 peptide (18F-AlF-NOTA-PRGD2, denoted as 18F-alfatide) using a fluo-ride–aluminum complex that significantly simplified the labeling procedure. Methods Nine patients with a primary diagnosis of lung cancer were examined by both static and dynamic PET imaging with 18F-alfatide, and 1 tuberculosis patient was investigated using both 18F-alfatide and 18F-FDG imaging. Standardized uptake values were measured in tumors and other main organs at 30 min and 1 h after injection. Kinetic parameters were calculated by Logan graphical analysis. Immunohisto-chemistry and staining intensity quantification were performed to confirm the expression of integrin αvβ3. Results Under the optimal conditions, the whole radiosynthesis including purifica-tion was accomplished within 20 min with a decay-corrected yield of 42.1% ± 2.0% and radiochemical purity of more than 95%. 18F-alfatide PET imaging identified all tumors, with mean standardized uptake values of 2.90 ± 0.10. Tumor-to-muscle and tumor-to-blood ratios were 5.87 ± 2.02 and 2.71 ± 0.92, respectively. Conclusion 18F-alfatide can be produced with excellent radiochemical yield and purity via a simple, 1-step, lyophilized kit. PET scanning with 18F-alfatide allows specific imaging of αvβ3 expression with good contrast in lung cancer patients. This technique might be used for the assessment of angiogene-sis and for planning and response evaluation of cancer therapies that would affect angiogenesis status and integrin expression levels.