Preperation of Gene-loaded Quantum Dots as Self-illuminating Probes for Cell Imaging

doi:10.7517/issn.1675-0475.180503

Abstract

Abstract: To identify whether the CS-Qdots could act as gene carriers and self-illuminating probes simultaneously as delivering luciferase genes to cells. CdTe quantum dots were prepared and coated with chitosan to construct CS-Qdots nanoparticles. Then the CdTe and CS-Qdots nanoparticles were characterized; the excitation of CS-Qdots tested by bioluminescence in vivo. The reporter genes pCMV-luciferase were deliveried into cells by CS-Qdots and the wavelength of bioluminescence was tested to identify the pCMV-luciferase gene loaded CS-Qdots could act as the gene nanocarriers and self-illuminating probes simultaneously. The morphology of CdTe quantum dots and CS-Qdots nanoparticle were observed by TEM and were found to be spherical and good dispersion. The size of the fluorescent crystal was about 5 nm and the CS-Qdots nanoparticles were about 25-30 nm. When CdTe quantum dots were encapsulated by chitosan, the characteristic peaks of chitosan were observed on the FTIR spectra. The surface charge of CdTe-Qdots was -16.31±0.91 mV and then turned to a positive value of 28.02±1.15 mV. Dynamic light scattering measurements showed that the mean hydrodynamic diameter of CdTe quantum dots was 102.7±4.4 nm, and the mean hydrodynamic diameter of CS-Qdots nanoparticles was 583.0±13.7 nm. Spectral analysis showed that the CdTe quantum dots have wide absorption spectrum and the emission spectrum was narrow and symmetrical. By agarose gel electrophoresis, the plasmid pCMV-luciferase binding affinity of CS-Qdots was tested and the complete retardation was observed over the particle/DNA weight ratio of 10:1. In vivo test CS-Qdots could be directly excited by bioluminescent cells surrounded. When cells were transfected with pCMV-luciferase DNA by using CS-Qdots as gene carriers in vivo or in vitro, the emission peak of bioluminescence could red-shift from 560 to 630 nm, which means the CS-dots could be activated by bioluminescence. It is concluded that the luciferase gene-loaded CS-Qdots could act as wavelength-tunable self-illuminating probes and improve tumor optical molecular imaging.

Key words: optical imaging, quantum dots, bioluminescence, self-illuminating

YUAN Chenyan, AN Yanli. Preperation of Gene-loaded Quantum Dots as Self-illuminating Probes for Cell Imaging[J]. Imaging Science and Photochemistry, 2018, 36(6): 467-477.

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