Nanotheranostics 2018; 2(2):157-167. doi:10.7150/ntno.22988

Research Paper

Fabrication of Positively Charged Fluorescent Polymer Nanoparticles for Cell Imaging and Gene Delivery

Lin Wei1, Di Zhang2, Xuanfang Zheng1, Xuyao Zeng2, Youlin Zeng1, Xinbo Shi3, Xin Su4, Lehui Xiao✉,2

1. Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research, Ministry of Education, Key Laboratory of Phytochemical R&D of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan, 410081, China;
2. State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry, Nankai University, Tianjin, 300071, China;
3. Hunan Provincial Key Laboratory of Food Science and Biotechnology, College of Food Science and Technology, Hunan Agricultural University, Changsha, 410128, China;
4. Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China.
W. L., D. Z. and X. Z. contributed equally to this work.

This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY-NC) license ( See for full terms and conditions.
Wei L, Zhang D, Zheng X, Zeng X, Zeng Y, Shi X, Su X, Xiao L. Fabrication of Positively Charged Fluorescent Polymer Nanoparticles for Cell Imaging and Gene Delivery. Nanotheranostics 2018; 2(2):157-167. doi:10.7150/ntno.22988. Available from

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Development of efficient non-viral gene delivery vector has aroused great attention in the past few decades. In this study, we reported a new gene delivery vector, positively charged fluorescent conjugated polymer nanoparticles (CPNPs), for efficient gene transfection and in-situ intracellular fluorescence imaging. The microscopic and spectroscopic characterizations demonstrated that these CPNPs possess decent fluorescence performance (e.g. with fluorescence quantum yield of 70.7±0.3%) and small size dimension of ~3.6±0.3 nm (DLS result). Fast and efficient cellular translocation capability was observed according to the time-dependent living cell imaging experiments. Nearly all of the cells were loaded with CPNPs after co-incubation for 2 h regardless of the cell type. In comparison with the commonly used gene delivery vector, lipofectamine 2000 (with gene transfection efficiency of 55±5% for pEGFP), the gene expression efficiency with the positively charged CPNPs (70±3% for pEGFP) was improved significantly. Intracellular fluorescence imaging results demonstrated that the CPNPs could actively assemble close to the periphery of nuclei. Disassembly was not observed even 36 h later, which greatly facilitates releasing of pDNA close to the periphery of nuclei and thus promotes the gene transfection efficiency.

Keywords: Conjugated polymer nanoparticles, Gene delivery, Single particle imaging, Living cell imaging, Fluorescence microscopy.