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

Abstract

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 (1 H NMR) spectroscopy, and 13 C 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-polyaminemorpholine 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.

Quantum Dots: An Emerging Approach for Cancer Therapy

“…Zhang et al, created a lysosome-targetable fluorescent probe using L-cysteine-polyamine-morpholine-modified QDs in the 4-5 nm size range. Modified QDs fluoresced brightly in HeLa cells and targeted the cells' lysosomes, according to the findings (Figure 3) (Zhang et al, 2020).…”

“…Graphitic carbon nitride QDs (g-CNQDs) was produced by Zhang et al, 2020, for bioimaging, medication delivery, and photodynamic therapy (Zhang et al, 2020).…”

BODIPYs in PDT: A Journey through the Most Interesting Molecules Produced in the Last 10 Years

“…In 2019 Wang et al, obtained a BODIPY able to specifically targeting lysosomes [ 115 ]. The molecule obtained ( BDPI-Lyso ) has iodine atoms to generate 1 O 2 and morpholine for targeting specifically the lysosomes ( Figure 11 ) [ 116 , 117 , 118 ].…”

Time- and Spectrally-Resolved Photoluminescence Study of Alloyed CdxZn1−xSeyS1−y/ZnS Quantum Dots and Their Nanocomposites with SPIONs in Living Cells

“…Similar principles are presented in the study by Zhou et al [ 29 ]. Any information on average PL decay time can rarely be found for QDs, while one of the fundamental distinctions of QDs from organic luminophores, namely multiexponentiality of PL decay, is almost never taken into consideration [ 30 ]. Possible reasons for the multi-exponential nature of the QD PL decay are the presence of a ”dark” state [ 31 ], from which the transition to the ground state is spin-forbidden, as well as “blinking,” that is, the ability of nanocrystals to randomly switch between states with different rates of non-radiative relaxation of electronic excitation [ 32 ].…”