State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun, Jilin 130012, P. R. China.
Key Laboratory of Bionic Engineering (Ministry of Education), College of Biological and Agricultural Engineering, Jilin University, Changchun, Jilin 130022, P. R. China.
Biomater Sci. 2022 Aug 24;10(17):4764-4772. doi: 10.1039/d2bm00516f.
Conjugated polymer dots (Pdots) are often used as excellent fluorescent probes in the biomedical field. In the process of preparing Pdots, the rapid change of the solvent polarity will result in a messy and defective stacking of the polymer chains in the particle, and these stacking defects of the polymer chains may weaken its luminescence properties. Here, we try to optimize the stacking of the conjugated polymer chains by the thermal annealing treatment. After the low temperature thermal treatment, the fluorescence intensity of Pdots can be enhanced by about 11%-29%, and Pdots maintain their original stability and biosafety. We used transmission electron microscopy (TEM) and single particle fluorescence imaging to reveal the possible mechanism of the chain stacking optimization process, that is, the thermal annealing process of Pdots is the competition between internal chain rearrangement in the particle and particle aggregation. The luminescence-enhanced Pdots exhibit good cellular imaging performance. These results prove that it is feasible to extend the thermal annealing treatment from planar polymer devices to polymer nanoparticles. It provides the possibility to realize stable and complex biological imaging applications using Pdots with a simple molecular structure, and a mature improvement scheme for the mass preparation of Pdots.
共轭聚合物点（Pdots）通常被用作生物医学领域中优异的荧光探针。在制备 Pdots 的过程中，溶剂极性的快速变化会导致颗粒中聚合物链的杂乱和缺陷堆积，这些聚合物链的堆积缺陷可能会削弱其发光性能。在这里，我们试图通过热退火处理来优化共轭聚合物链的堆积。经过低温热处理，Pdots 的荧光强度可以增强约 11%-29%，并且 Pdots 保持其原始的稳定性和生物安全性。我们使用透射电子显微镜（TEM）和单颗粒荧光成像来揭示链堆积优化过程的可能机制，即 Pdots 的热退火过程是颗粒内部链重排和颗粒聚集之间的竞争。发光增强的 Pdots 表现出良好的细胞成像性能。这些结果证明，将热退火处理从平面聚合物器件扩展到聚合物纳米颗粒是可行的。它为使用具有简单分子结构的 Pdots 实现稳定和复杂的生物成像应用提供了可能性，并且为 Pdots 的大规模制备提供了成熟的改进方案。
