A non-conjugated polyethylenimine copolymer-based unorthodox nanoprobe for bioimaging and related mechanism exploration.
Leihou ShaoKaiwei WanHui WangYankun CuiCaiyan ZhaoJianqing LuXianlei LiLong ChenXinyue CuiXuan WangXiongwei DengXinghua ShiYan WuPublished in: Biomaterials science (2019)
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.
Keyphrases
- quantum dots
- living cells
- energy transfer
- fluorescent probe
- molecular dynamics simulations
- oxide nanoparticles
- photodynamic therapy
- single molecule
- working memory
- atomic force microscopy
- magnetic resonance imaging
- molecular docking
- single cell
- drug delivery
- mass spectrometry
- high intensity
- drug induced
- contrast enhanced
- tissue engineering