Dark-Field Microscopic Study of Cellular Uptake of Carbon Nanodots: Nuclear Penetrability

Carbon nanodots are fascinating candidates for the field of biomedicine, in applications such as bioimaging and drug delivery. However, the nuclear penetrability and process are rarely studied and lack understanding, which limits their applications for drug carriers, single-molecule detection and live cell imaging. In this study, we attempt to examine the uptake of CNDs in cells with a focus on the potential nuclear penetrability using enhanced dark-field microscopy (EDFM) associated with hyperspectral imaging (HSI) to quantitatively determine the light scattering signals of CNDs in the cells. The effects of both CND incubation time and concentration are investigated, and plausible nuclear penetration involving the nuclear pore complex (NPC) is discussed. The experimental results and an analytical model demonstrate that the CNDs' uptake proceeds by a concentration-dependent three-stage behavior and saturates at a CND incubation concentration larger than 750 mu g/mL, with a half-saturated concentration of 479 mu g/mL. These findings would potentially help the development of CNDs' utilization in drug carriers, live cell imaging and other biomedical applications.

Automated summary

This study examines the uptake of carbon nanodots (CNDs) in cells and their potential nuclear penetrability using enhanced dark-field microscopy (EDFM) and hyperspectral imaging (HSI). The effects of CND incubation time and concentration on uptake are investigated, and the possible involvement of the nuclear pore complex (NPC) in nuclear penetration is discussed. Experimental results and an analytical model show that CND uptake follows a concentration-dependent three-stage behavior.