One-dimensional Europium-coordination polymer as luminescent sensor for highly selective and sensitive detection of 2,4,6-trinitrophenol.

Three isostructural lanthanide coordination polymers (LnCPs), [Ln(L)6(DMF)]n {HL = 2-(2-formylphenoxy) acetic acid, Ln = Sm (1); Eu (2); Tb (3)} have been synthesized by solvothermal reaction and characterized. Single crystal analyses revealed that the architectures of these LnCPs own one dimensional chain which can be further packed into two-dimensional architectures by hydrogen bonds. Moreover, these LnCPs can offer strategically placed uncoordinated formyl groups, which may act as hydrogen-bond acceptor in the sensing of nitro explosives. Luminescence measurements reveal that LnCPs 2 and 3 exhibit strong luminescence in solid states. LnCP 2 shows quick, highly selective and sensitive detection of 2,4,6-trinitrophenol (TNP) with the high quenching constant (2.6 × 104 M-1) and low detection limit (3.39 µM), which indicates that LnCP 2 is more efficient than most of Eu-based coordination polymers for the sensing of TNP. Furthermore, LnCP 2 represents the first example of one-dimensional Eu-based sensors with formyl group as hydrogen-bonding site in the detection of TNP.

Fabrication and biological imaging of hydrazine hydrate cross-linked AIE-active fluorescent polymeric nanoparticles.

Amphiphilic copolymers play a paramount role in the fabrication of fluorescent polymeric nanoparticles (FPNs) through the self-assembly procedure. In this work, novel hydrazine hydrate cross-linked amphiphilic poly(PEG­co­FHMA) copolymers were constructed via reversible addition-fragmentation chain transfer (RAFT) polymerization, containing an aggregation-induced emission (AIE) active hydrophobic moiety and a hydrophilic poly(ethylene glycol) (PEG) group. Different characterization techniques have been employed to confirm their successful synthesis. Due to their amphiphilic property, the resulting poly(PEG­co­FHMA) copolymers can self-assemble into FPNs in aqueous solution and form poly(PEG­co­FHMA) FPNs with size ranging from 100 to 200 nm. The investigation of photophysical properties demonstrated poly(PEG­co­FHMA) FPNs possess strong fluorescence, large Stokes shift, excellent AIE characteristic, low critical micelle concentration and remarkable photostability. Biological assay results suggested that these cross-linked AIE-active FPNs are of low toxicity and excellent cell dyeing performances. All of these features make them promising candidates for biomedical applications. As compared with typical AIE-active FPNs based on the synthetic AIE-active compounds, the novel cross-linked AIE-active FPNs based on the Schiff base is rather simple, good designable and universal. More importantly, this strategy could also be adopted for preparation of a large number of AIE-active FPNs because of the well designability of copolymers and salicylaldehyde derivatives. Thus this work will provide a novel route for preparation of multifunctional AIE-active FPNs in a rather facile manner.

A facile strategy for fabrication of aggregation-induced emission (AIE) active fluorescent polymeric nanoparticles (FPNs) via post modification of synthetic polymers and their cell imaging.

Aggregation-induced emission (AIE) active fluorescent polymeric nanoparticles (FPNs) have recently emerged as the promising nanoprobes for biological imaging for their intensive fluorescence, good photostability, desirable biocompatibility and well designability of structure and optical properties. Herein, we proposed a novel strategy for fabrication of AIE-active FPNs through the post modification of synthetic copolymers to form Schiff base. The size, morphology, optical properties and biocompatibility as well as cell uptake behavior were evaluated in detailed. To fabricate these AIE-active FPNs, poly(PEG-co-VA) copolymers were first obtained via addition-fragmentation chain transfer polymerization using poly(ethylene glycol) methyl ether methacrylate (PEGMA) and 3-vinylaniline (VA) as the monomers. Then the AIE-active SA-poly(PEG-co-VA) FPNs were formed through the reaction between salicylaldehyde (SA) and VA. Results demonstrated that SA-poly(PEG-co-VA) FPNs possess bright fluorescence, superior photo-bleaching resistance, excellent biocompatibility and efficient cell uptake behavior. To the best of our knowledge, this is the first report for fabrication AIE-active FPNs through post modification of synthetic copolymers. The facile fabrication procedure and the remarkable features suggested that these AIE-active FPNs promising candidates for biomedical applications.