Although the underlying origin is still vague, the fact that the C-dots keep its PL intensity at a relatively high level, going through the pH value from very acidic to neutral, shows promising advantages

in biological applications. Laser scanning confocal microscopy imaging in vitro Figure 4 shows the 2D images of Tozasertib nmr MGC-803 cells labeled with RNase A@C-dots. After co-incubation with RNase Palbociclib molecular weight A@C-dots, MGC-803 cells show bright green color over the entire cell upon excitation at 405 nm. The nuclei marked by PI, when excited at 536 nm, featured strong red fluorescence. A merge image clearly shows that the RNase A@C-dots can enter the cell via the endocytic route. Moreover, we can also find that in up to 10% cells, there are clearly green dots existing in the nucleus. Meanwhile, a 3D confocal imaging (Figure 5) of the

cell clearly reveals that the RNase A@C-dots have entered the cell, while the carbon dots reported before [7] were mostly in the cytoplasm and membrane, with only minor penetration into the cell nucleus. Until now, we can give an explanation for the transportation into the nucleus. It may be caused by the small size of RNase A@C-dots which enables perfect dispersion or assists protein (derived from RNase A) action. Figure 4 Laser scanning confocal microscopy images of MGC-803 cells. (a) Picture of MGC-803 cells under white light. (b) Picture of MGC-803 cells JQ-EZ-05 in vitro under ADP ribosylation factor excitation at 405 nm. (c) Picture of MGC-803 cells under excitation at 536 nm. (d) Overlapping picture of MGC-803 cells under excitation at 405 and 536 nm. (e) Amplified picture of a single

MGC-803 cell under white light. (f) Amplified picture of a single MGC-803 cell under excitation at 405 nm. (g) Amplified picture of a single MGC-803 cell under excitation at 536 nm. (h) Overlapping picture of a single MGC-803 cell under excitation at 405 and 536 nm. Figure 5 Laser scanning confocal microscopy images (3D mode) of MGC-803 cells. Cytotoxicity assay by MTT and real-time cell electronic sensing To test the potential of the RNase A@C-dots in cancer therapy, MTT assay was used to determine the cytotoxicity profile. The different concentrations of RNase A@C-dots were incubated with MGC-803 cells, respectively, for 24 h at 37°C. In control experiments, we select RNase A and C-dots to carry out accordingly the same procedure and keep equal contents of bare C-dots with RNase A@C-dot solution. The results (Figure 6a) show clearly that RNase A alone could restrain the cancerous cells due to the ribonuclease-mediated toxicity [27]. Moreover, the ability of RNase A in inhibiting the cancerous cells exhibits a content-dependent character with a relatively low cell viability (61%) at higher concentration (300 μg/ml) and a high one at lower concentration (36.5 μg/ml).