Cationic polymer-derived carbon dots for enhanced gene delivery and cell imaging

Carbon dots have attracted rapidly growing interest in recent years. In this report, we prepared two cationic polymer-derived carbon dots (Taea-CD and Cyclen-CD, collectively called C-dots) via a hydrothermal method. Transmission electron microscopy (TEM) results show that the C-dots were sphere-like and the size distribution was 1.8 ± 0.4 nm for Taea-CD and 5.4 ± 2 nm for Cyclen-CD. The C-dots emitted bright blue fluorescence under UV light (365 nm). Confocal laser scanning microscopy (CLSM) assay indicates that the C-dots-mediated transfection process could be detected in real time, and their tunable fluorescence emission under different wavelengths could satisfy varying requirements. Luciferase assay indicates that the transformation from the polymer to CD is an effective strategy to improve the transfection efficiency (TE) of the materials. Moreover, the C-dots also exhibit higher serum tolerance and cell viability than commercially available polyethyleneimine (PEI). These results demonstrate that the preparation of carbon dots from polymers is a promising method for developing multifunctional gene vectors with high TE and biocompatibility.

Colloidal Nanobioconjugate with Complementary Surface Chemistry for Cellular and Subcellular Targeting

Chemically and biochemically functionalized colloidal nanoparticles with appropriate surface chemistry are essential for various biomedical applications. Although a variety of approaches are now available in making such functional nanoparticles and nanobioconjugates, the lack of complementary surface chemistry often leads to poor performance with respect to intended biomedical applications. This feature article will focus on our efforts to make colloidal nanobioconjugates with appropriate/complementary surface chemistry for better performance of a designed nanoprobe with respect to cellular and subcellular targeting applications. In particular, we emphasize polyacrylate-based coating chemistry followed by a conjugation strategy for transforming <10 nm inorganic nanoparticle to colloidal nanoprobe of 20-50 nm hydrodynamic size. We show that a colloidal nanoprobe can be chemically designed to control the cell-nanoparticle interaction, cellular endocytosis, and targeting/labeling of subcellular compartments. Further study should be directed to adapt this surface chemistry to different nanoparticles, fine tune the surface chemistry for targeting/imaging on the subcellular/molecular length scale, and develop a delivery nanocarrier for subcellular compartments.