Cellular uptake, intracellular behavior, and acute/sub-acute cytotoxicity of a PEG-modified quantum dot with promising in-vivo biomedical applications

Qingyuan Cheng; Yiping Duan; Wei Fan; Dongxu Li; Cuiwen Zhu; Tiantian Ma; Jie Liu; Mingxia Yu

doi:10.1016/j.heliyon.2023.e20028

Cellular uptake, intracellular behavior, and acute/sub-acute cytotoxicity of a PEG-modified quantum dot with promising in-vivo biomedical applications

Heliyon. 2023 Sep 9;9(9):e20028. doi: 10.1016/j.heliyon.2023.e20028. eCollection 2023 Sep.

Authors

Qingyuan Cheng^{1

2}, Yiping Duan³, Wei Fan⁴, Dongxu Li¹, Cuiwen Zhu¹, Tiantian Ma¹, Jie Liu⁵, Mingxia Yu¹

Affiliations

¹ Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China.
² Department of Andrology/Sichuan Human Sperm Bank, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China.
³ Department of Laboratory Medicine, the Third Hospital of Wuhan, Wuhan, Hubei, China.
⁴ Department of Pathology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China.
⁵ Department of Endocrinology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China.

Abstract

Quantum Dots (QDs) modified with branched Polyethylene Glycol-amine (6- or 8-arm PEG-amine) coupled with methoxy PEG (mPEG) hold great promise for in vivo biomedical applications due to a long half-life in blood and negligible toxicity. However, the potential risks regarding their concomitant prolonged co-incubation with cardiovascular and blood cells remains inconclusive. In the present study, the feasible, effective and convenient proliferating-restricted cell line models representing the circulatory system were established to investigate the cellular internalization followed by intracellular outcomes and resulting acute/sub-acute cytotoxicity of the 6-arm PEG-amine/mPEG QDs. We found a dose-, time- and cell type-dependent cellular uptake of the 6-arm PEG-amine/mPEG QDs, which was ten-fold lower compared to the traditional linear PEG-modified counterpart. The QDs entered cells via multiple endocytic pathways and were mostly preserved in Golgi apparatus for at least one week instead of degradation in lysosomes, resulting in a minimal acute cytotoxicity, which is much lower than other types of PEG-modified QDs previously reported. However, a sub-acute cytotoxicity of QDs were observed several days post exposure using the concentrations eliciting no-significant acute cytotoxic effects, which was associated with elevated ROS generation caused by QDs remained inside cells. Finally, a non-cytotoxic concentration of the QDs was identified at the sub-acute cytotoxic level. Our study provided important information for clinical translation of branched PEG-amine/mPEG QDs by elucidating the QDs-cell interactions and toxicity mechanism using the proliferation-restricted cell models representing circulatory system. What's more, we emphasized the indispensability of sub-acute cytotoxic effects in the whole biosafety evaluation process of nanomaterials like QDs.

Keywords: Cellular uptake; Intracellular behavior; Polyethylene glycol modification; Quantum dots; Sub-acute cytotoxicity.