Labeling and in vivo visualization of transplanted adipose tissue-derived stem cells with safe cadmium-free aqueous ZnS coating of ZnS-AgInS2 nanoparticles

Abstract

The facile synthesis of ZnS-AgInS2 (ZAIS) as cadmium-free QDs and their application, mainly in solar cells, has been reported by our groups. In the present study, we investigated the safety and the usefulness for labeling and in vivo imaging of a newly synthesized aqueous ZnS-coated ZAIS (ZnS-ZAIS) carboxylated nanoparticles (ZZC) to stem cells. ZZC shows the strong fluorescence in aqueous solutions such as PBS and cell culture medium, and a complex of ZZC and octa-arginine (R8) peptides (R8-ZZC) can achieve the highly efficient labeling of adipose tissue-derived stem cells (ASCs). The cytotoxicity of R8-ZZC to ASCs was found to be extremely low in comparison to that of CdSe-based QDs, and R8-ZZC was confirmed to have no influence on the proliferation rate or the differentiation ability of ASCs. Moreover, R8-ZZC was not found to induce the production of major inflammatory cytokines (TNF-α, IFN-γ, IL-12p70, IL-6 and MCP-1) in ASCs. Transplanted R8-ZZC-labeled ASCs could be quantitatively detected in the lungs and liver mainly using an in vivo imaging system. In addition, high-speed multiphoton confocal laser microscopy revealed the presence of aggregates of transplanted ASCs at many sites in the lungs, whereas individual ASCs were found to have accumulated in the liver.

Nanostructure Engineering of Size-Quantized Semiconductor Particles for Photoelectrochemical Applications

“…Cd-based binary nanoparticles have often been used to this end, but we reported the utility of ZAIS particles with visible light emission as a Cd-free probe for cell imaging. 67,68 ZAIS nanoparticles incorporated into living cells enabled clear PL imaging with much less cytotoxicity than that observed for conventional Cd-based binary nanoparticles due to the absence of released Cd 2+ ions. 67 On the other hand, it is well known that near-IR light is more efficiently transmitted through biological tissues than is light in the ultraviolet, visible, or IR wavelength region.…”

Click Chemistry as a Tool for Cell Engineering and Drug Delivery

“…As such, the labeled cells can be monitored not only by fluorescence and bioluminescence imaging but also by positron emission tomography (PET), computed tomography (CT), and magnetic resonance (MR) imaging after transplantation [59,60,61,62]. MR imaging is able to detect a small number of transplanted cells in deep tissues [63]. Furthermore, the cell tracking method involves a short reaction time and label cells with high efficacy.…”

In Vivo Imaging Technology of Transplanted Stem Cells Using Quantum Dots for Regenerative Medicine

“…For example, the ZnS-ZAIS QDs developed in our studies were confirmed to have cytotoxicity against stem cells that was about 100 times lower than that of CdSe/ZnS QDs. 22 Shang et al onfirmed that GQDs could label human neural stem cells (hNSCs). 36 Almost all non-toxic organic dyes can easily label stem cells through the cell membrane due to low molecular weight and size by the addition of these dyes to cell culture medium.…”

“…QDs with a negatively charged surface and R8 peptide were complexed at an optimum concentration ratio for 15 min, and then the solution including QDs and R8 complexes was added to the cell culture medium. After that, QDs were confirmed to be transduced into cells by the endocytosis pathway within at least 24 h. 12,[14][15][16]22 Meanwhile, Liu et al showed the carbon and graphene dots with various surface passivation schemes by organic or biomolecules ( Fig. 2a).…”

“…Stem cell labeling technologies using QDs and in vivo fluorescence imaging technologies of transplanted stem cells have been explored by our group since 2008. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] In this review paper, we mainly overview our research topics, including QD types, stem cell labeling methods by QDs and in vivo fluorescence imaging of transplanted stem cells labeled with QDs.…”