A study on effects of naphthalimide derivative-capped quantum dots on the cellular internalization, proliferation, and apoptosis ability

The Biological Activity Research of the Nano-Drugs Based on 5-Fluorouracil-Modified Quantum Dots

PURPOSE

Over the past decades, quantum dots (QDs) have shown the broad application in diverse fields, especially in intracellular probing and drug delivery, due to their high fluorescence intensity, long fluorescence lifetime, strong light-resistant bleaching ability, and strong light stability. Therefore, we explore a kind of therapeutic potential against cancer with fluorescent imaging.

METHODS

In the current study, a new type of QDs (QDs@L-Cys-TAEA-5-FUA) capped with L-cysteine (L-Cys) and tris(2-aminoethyl)amine (TAEA) ligands, and conjugated with 5-fluorouracil-1-acetic acid (5-FUA) has been synthesized. Ligands were characterized by electrospray ionization mass spectrometry and H-nuclear magnetic resonance (1H NMR) spectroscopy. The modified QDs were characterized by transmission electron microscopy, ultraviolet and visible spectrophotometry (UV-Vis), and fluorescence microscopy. And the biological activity of modified QDs was explored by using MTT assay with HeLa, SMMC-7721 HepG2, and QSG-7701 cells. The fluorescence imaging of modified QDs was obtained by fluorescence microscope.

RESULTS

The modified QDs are of controllable sizes in the range of 4-5 nm and they possess strong optical emission properties. UV-Vis and fluorescence spectra demonstrated that the L-Cys-TAEA-5-FUA was successfully incorporated into QD nanoparticles. The MTT results demonstrated that L-Cys-TAEA-5-FUA modified QDs could efficiently inhibit the proliferation of cancer cells as compared to the normal cells, illustrating their antitumor efficacy. The mechanistic studies revealed that the effective internalization of modified QDs inside cancer cells could inhibit their proliferation, through excessive production of intracellular reactive oxygen species, leading to apoptosis process.

CONCLUSION

The present study suggests that modified QDs can enter cells efficiently and could be employed as therapeutic agents for the treatment of various types of cancers with fluorescent imaging.

A Lysosome-Targetable Fluorescence Probe Based on L-Cysteine-Polyamine-Morpholine-Modified Quantum Dots for Imaging in Living Cells

PURPOSE

Quantum dots (QDs) are used as fluorescent probes due to their high fluorescence intensity, longevity of fluorescence, strong light-resistant bleaching ability and high light stability. Therefore, we explore a more precise probe that can target an organelle.

METHODS

In the current study, a new class of fluorescence probes were developed using QDs capped with 4 different L-cysteine-polyamine-morpholine linked by mercapto groups. Ligands were characterised by Electrospray ionization mass spectrometry (ESI-MS), H-Nuclear Magnetic Resonance (1H NMR) spectroscopy, and 13C NMR spectroscopy. Modified QDs were characterized by Transmission Electron Microscope (TEM), Ultraviolet and visible spectrophotometry (UV-Vis), and fluorescence microscopy. And the biological activity of modified QDs was explored by using MTT assay with HeLa, SMMC-7721 and HepG2 cells. The fluorescence imaging of modified QDs was obtained by confocal laser scanning fluorescence microscopy (CLSM).

RESULTS

Synthesized QDs ranged between 4 to 5 nm and had strong optical emission properties. UV-Vis and fluorescence spectra demonstrated that the cysteine-polyamine-morpholine were successfully incorporated into QD nanoparticles. The MTT results demonstrated that modified QDs had lesser cytotoxicity when compared to unmodified QDs. In addition, modified QDs had strong fluorescence intensity in HeLa cells and targeted lysosomes of HeLa cells.

CONCLUSION

This study demonstrates the modified QDs efficiently entered cells and could be used as a potential lysosome-targeting fluorescent probe.

Dual-functional carbon dots–silver@zinc oxide nanocomposite: in vitro evaluation of cellular uptake and induction of apoptosis

We report here the devleopment of novel CDs decorated on a silver–zinc oxide (CD–Ag@ZnO) nanocomposite (NC) consisting of highly fluorescent CDs and Ag@ZnO.