An Unconventional Polymerization Route to Hydrophilic Fluorescent Organic Nanoparticles for Multicolor Cellular Bioimaging

Abstract

We demonstrated an unconventional polymerization route to synthesize hydrophilic fluorescent organic nanoparticles (FONs) for multicolor cellular bioimaging in this contribution. The route benefits from our unexpected discovery of a rapid polymerization reaction between 1,6-hexanediol dipropiolate and 2,4,6-triazide-1,3,5-triazine under the catalysis of N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDETA). Interestingly, the 2,4,6-triazide-1,3,5-triazine and PMDETA system can also induce rapid free radical polymerization at room temperature. The as-prepared FONs exhibited promising water solubility and stability with an average diameter of 20 nm. The excitation wavelength-dependent fluorescent properties endow the FONs with blue, yellow, and red fluorescent emission under UV, blue, and green excitation, respectively. The cytotoxicity of FONs was investigated by using a Cell Counting Kit (CCK-8) assay, which indicated good biocompatiblity. More importantly, the cell uptake experiment verified the FONs were excellent fluorescent nanoprobes for multicolor cellular bioimaging. Therefore, this unconventional route provides a novel fabrication strategy of highly hydrophilic FONs for biomedical applications.

Truly Multicolor Emissive Hyperbranched Polysiloxane: Synthesis, Mechanism Study, and Visualization of Controlled Drug Release

“…Surprisingly, the QYs of HBPSi-β-CD after being excited by 360, 420, 450, and 550 nm reach 19.36, 31.46, 46.14, and 44.84%, respectively (Figure C). Therefore, different from HBPSi-NH 2 and the reported unconventional fluorescent polymers, ,,,, HBPSi-β-CD has high QYs from blue to red emission, showing truly multicolor emission. The high QY of HBPSi-β-CD might be caused by the combination of the rigid β-cyclodextrin and flexible HBPSi-NH 2 . − , The different nature between HBPSi-NH 2 and HBPSi-β-CD is further confirmed by their fluorescence lifetimes.…”

“…Unconventional fluorescent polymer generally exhibits excitation-dependent fluorescence, which might be caused by the following reasons: (i) the immense structural heterogeneity and broad molecular weight distribution; , (ii) the morphologies of polymer aggregates are heterogeneous, and the emission wavelength is size-dependent; − (iii) the electron-rich atom cluster or electron delocalization formed in the polymer aggregates is heterogeneous. ,, Such interesting property endows unconventional fluorescent polymer ability for emitting blue, green, yellow, and red fluorescence under different excitations. For example, Kong’s group found polymer dots with π bonds could emit blue, yellow, and red light. Zhang et al synthesized a multicolor polymer by introducing azido groups to the molecular structure of poly­(vinylidene fluoride) .…”

Self‐fluorescent polymers for bioimaging

“…Recently, Ban and coworkers reported the organic-base-catalyzed polymerization of 1,6hexanediol dipropiolate and 2,4,6-triazide-1,3,5-triazine to produce nitrogen-and oxygen-containing fluorescent nanoparticles (Figure 5B). [49] Cell experiments verified that these fluorescent nanoparticles are excellent fluorescent nanoprobes for multicolor cellular bioimaging under UV-, blue-, and green-light excitation (Figure 5B1-B3). Although all these above-mentioned self-fluorescent polymers with nitrogen-containing chromophores have been used for fluorescence bioimaging, their intrinsic fluorescence mechanisms are still debatable.…”

“…Reproduced with permission. [49] Copyright 2018, Wiley-VCH containing tertiary amine chromophores were produced and aimed at avoiding some possible drawbacks, such as cytotoxicity and photobleaching. [47] Owing to these considerations, Sun and coworkers prepared alicyclic tertiary-amine-containing self-fluorescent polymers (Figure 5A).…”

High-Efficiency Long-Wavelength Fluorescent Hyperbranched Polysiloxanes: Synthesis, Emission Mechanism, Information Encryption, and Film Preparation

“…For example, as shown in the inserted digital pictures in Figure b–d, pure HBPSi-Phe, HBPSi-Tyr, and HBPSi-Trp emit cyan, orange, and green light under excitation of 405 nm light. Usually, the emission intensity of unconventional fluorescent polymers drops sharply with increasing the excitation wavelength. ,,,, However, as Figure c,d shows, HBPSi-Tyr and HBPSi-Trp have a high emission intensity in the emission region of 450–620 nm. Especially, the ratios of the emission intensity under excitation of 520 nm to the emission under excitation of 440 nm of HBPSi, HBPSi-Ben, HBPSi-Tyr, and HBPSi-Trp are 0.11, 0.36, 0.78, and 0.69, indicating that the introduced aromatic amino acids enlarge the spatial electronic delocalizations and then endow HBPSi with an excellent long-wavelength emission property. , …”