Improving cytocompatibility of CdTe quantum dots by Schiff-base-coordinated lanthanides surface doping

Abstract

BackgroundSuitable fluorophores are the core of fluorescence imaging. Among the most exciting, yet controversial, labels are quantum dots (QDs) with their unique optical and chemical properties, but also considerable toxicity. This hinders QDs applicability in living systems. Surface chemistry has a profound impact on biological behavior of QDs. This study describes a two-step synthesis of QDs formed by CdTe core doped with Schiff base ligand for lanthanides [Ln (Yb3+, Tb3+ and Gd3+)] as novel cytocompatible fluorophores.ResultsMicrowave-assisted synthesis resulted in water-soluble nanocrystals with high colloidal and fluorescence stability with quantum yields of 40.9–58.0%. Despite induction of endocytosis and cytoplasm accumulation of Yb- and TbQDs, surface doping resulted in significant enhancement in cytocompatibility when compared to the un-doped CdTe QDs. Furthermore, only negligible antimigratory properties without triggering formation of reactive oxygen species were found, particularly for TbQDs. Ln-doped QDs did not cause observable hemolysis, adsorbed only a low degree of plasma proteins onto their surface and did not possess significant genotoxicity. To validate the applicability of Ln-doped QDs for in vitro visualization of receptor status of living cells, we performed a site-directed conjugation of antibodies towards immuno-labeling of clinically relevant target—human norepinephrine transporter (hNET), over-expressed in neuroendocrine tumors like neuroblastoma. Immuno-performance of modified TbQDs was successfully tested in distinct types of cells varying in hNET expression and also in neuroblastoma cells with hNET expression up-regulated by vorinostat.ConclusionFor the first time we show that Ln-doping of CdTe QDs can significantly alleviate their cytotoxic effects. The obtained results imply great potential of Ln-doped QDs as cytocompatible and stable fluorophores for various bio-labeling applications.

Norepinephrine transporter-derived homing peptides enable rapid endocytosis of drug delivery nanovehicles into neuroblastoma cells

“…Among cell surface proteins, hNET is one of the best candidates for high-resolution homology modeling due to the recent elucidation of homolog proteins dDAT and hSERT [18]. Nanomedicine-based approaches are under development for targeting hNET via antibodies [22] or non-radioactive MIBG-linked ligands [23], and provide rational less-invasive alternative strategy to radiotherapy. The present work explores a better method of targeting hNET via non-toxic homing peptides.…”

Complex cytotoxicity mechanism of bundles formed from self-organised 1-D anodic TiO2 nanotubes layers

“…Haemocompatibility of TNTs was evaluated on commercially available human red blood cells (RBCs) (Zen-Bio, Durham, NC, USA) by adopting the protocol published in our previous study [47]. In addition, formation of protein coronas and activation of third complement component (C3) due to TNTs exposure in vitro were studied according to [48].…”

Towards an Understanding of Specific Response of Metallothionein (Sub)Isoforms to Exposure to Platinum-Based Anticancer Drugs

“…The relative quantity of the metallothioneins (MT1A, MT2A, MT3) were normalized against the reference gene, glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Fold change differences were determined using the 2-ΔΔCT method compared with untreated cells (Livak and Schmittgen, 2001;Buchtelova et al, 2018). Sequences of all primers used in qPCR analyses are listed in Tab.…”

“…After washing, membranes were incubated with antimouse horseradish peroxidase (HRP)-labelled secondary antibody (1:5,000, Dako, Santa Clara, CA, USA) for GAPDH and MT1, anti-rabbit HRPlabelled secondary antibody (1:5,000) for MT3 or streptavidin-conjugated HRP (1:35,000 in PBS-T) for 1 h at 20 ℃. Signals were developed using Clarity Western ECL Blotting Substrate (Bio-Rad, Hercules, CA, USA) and blots were visualized using Azure c600 imager (Azure Biosystems, Dublin, CA, USA) (Buchtelova et al, 2018).…”