Issue 7, 2019

A non-conjugated polyethylenimine copolymer-based unorthodox nanoprobe for bioimaging and related mechanism exploration

Abstract

Unconventional non-conjugated photoluminescent polymers have attracted increasing attention in bioimaging application, however their nonclassical photoluminescence mechanisms remain largely unclear. Herein, an amphiphilic copolymer polyethyleneimine-poly(D,L-lactide) (PEI-PDLLA) was synthesized and the obtained PEI-PDLLA copolymer exhibited intrinsic visible blue luminescence in the solid and concentrated solution states under 365 nm UV light irradiation. Using a computational assay approach, we investigated the unconventional photoluminescence mechanism of PEI-PDLLA. The results revealed that such photoluminescence should be related to the “clustered heteroatom chromophores” formed by through-space electronic interactions of N-heteroatoms in PEI. The copolymers can function as a fluorescent nanoprobe (PEI-PDLLA NPs) via a facile nanoprecipitation method and the self-assembly mechanism of PEI-PDLLA NPs was also investigated in-depth by molecular dynamics simulation. Intriguingly, the PEI-PDLLA NPs exhibited a remarkable excitation-dependent multi-wavelength emission characteristic, which was promising in acquiring a high precision imaging effect. Moreover, in contrast with conventional organic dyes with aggregation-caused quenching (ACQ), the fluorescence intensity of the PEI-PDLLA NPs was enhanced with increasing solution concentration. Furthermore, their applications in bioimaging indicated that PEI-PDLLA NPs could be utilized as a lysosome-specific and tumor-targeted nanoprobe with excellent photostability and good biocompatibility.

Graphical abstract: A non-conjugated polyethylenimine copolymer-based unorthodox nanoprobe for bioimaging and related mechanism exploration

Supplementary files

Article information

Article type
Paper
Submitted
01 Apr 2019
Accepted
09 May 2019
First published
15 May 2019

Biomater. Sci., 2019,7, 3016-3024

A non-conjugated polyethylenimine copolymer-based unorthodox nanoprobe for bioimaging and related mechanism exploration

L. Shao, K. Wan, H. Wang, Y. Cui, C. Zhao, J. Lu, X. Li, L. Chen, X. Cui, X. Wang, X. Deng, X. Shi and Y. Wu, Biomater. Sci., 2019, 7, 3016 DOI: 10.1039/C9BM00516A

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