A Novel Conjugated Polymer Consists of Benzimidazole and Benzothiadiazole: Synthesis, Photophysics Properties, and Sensing Properties for Pd 2+

Approaching Tryptophan-Derived Polynorbornene Fluorescent Chemosensors: Synthesis, Characterization, and Sensing Ability for Biomedical Applications as Biomarkers for Detecting Fe2+ Ions

We present a novel group of tryptophan (Trp)-based fluorescent polymeric probes synthesized via ring-opening metathesis polymerization (ROMP) of Trp-derived norbornene monomers. These probes, in mono- and disubstituted forms, incorporate amide and ester anchoring groups. The quantity of Trp substituents did not affect fluorescence selectivity but influenced quenching percentage. Poly-diamide-Trp, Poly-monoamide-Trp, Poly-diester-Trp, and Poly-monoester-Trp probes displayed selective detection of Fe2+ and Fe3+ ions with fluorescence on-off characteristics. Poly-diamide-Trp and Poly-monoamide-Trp exhibited a limit of detection (LOD) for Fe2+ and Fe3+ ions of 0.86-11.32 μM, while Poly-diester-Trp and Poly-monoester-Trp showed higher LODs (21.8-108.7 μM). These probes exhibited high selectivity over Fe2+, a crucial metal ion in the body known for its redox properties causing oxidative stress and cell damage. Cell cytotoxicity tests in various cell types confirmed biocompatibility. Additionally, Poly-diamide-Trp displayed excellent cell permeability and iron ion detection in EA.hy926 cells, suggesting potential for bioimaging and clinical applications.

A Fluorescent and Colorimetric Chemosensor Detecting Pd2+ Based on Chalcone Structure with Triphenylamine

A fluorometric and colorimetric chemosensor DiPP ((E)-3-(4-(diphenylamino)phenyl)-1-(pyridin-2-yl)prop-2-en-1-one) based on chalcone structure with a triphenylamine group was synthesized. Sensor DiPP detected Pd2+ with fluorescence turn-off and via colorimetry variation of yellow to purple. The binding ratio of DiPP to Pd2+ turned out to be 1 : 1. Detection limits for Pd2+ by DiPP were analyzed to be 0.67 µM and 0.80 µM through the fluorescent and colorimetric methods. Additionally, the fluorescent and colorimetric test strips were applied for probing Pd2+ and displayed that DiPP could obviously discriminate Pd2+ from other metals. The binding feature of DiPP to Pd2+ was presented by ESI-mass, Job plot, NMR titration, ESI-mass, and DFT calculations.

Poly(3-amino-carbazole) derivatives containing 1,10-phenanthroline and 8-hydroxyquinoline ligands: Synthesis, properties and application as ion sensors

As we know, excessive metal ions can even damage human health. Herein, two novel kinds of fluorescent sensing materials Poly(3-amino-carbazole) derivatives containing 1,10-phenanthroline and 8-hydroxyquinoline were synthesized and further applied to fluorescence detection for ions. The results show that Ni²⁺, Cu²⁺, and Pd²⁺ have excellent quenching effects on the fluorescence of Poly[9-(1,10-phenanthroline-2-yl)-9H-carbazol-3-amine] (PPNC), the LOD for these ions reaches 5.2 nM, 12.7 nM, 33.5 nM respectively. In the process of ion response, there is no shift of UV absorption peak, combined with IR spectra and theoretical calculation simulation, the quenching is considered to be caused by the coordination between metal ions and the second amine (-NH-) or 1,10-phenanthroline ligand of PPNC, which leads to the charge transfer from ligands to metal ions. In addition, an acid test was done for PPNC to verify and detect the presence of secondary amine (-NH-), and the results show that PPNC has good acid sensing ability which also supports the secondary amine (-NH-) structure. Finally, the paper test was performed on PPNC, indicating that PPNC has the potential for visual application.

BODIPY-based fluorescent polymeric probes for selective detection of Fe3+ ions in aqueous solution

It is of scientific and practical significance to sense and to remove heavy metal ions in the environment. In this work, four BODIPY-based fluorescent polymeric probes with the ability to sense and separate Fe3+ ions have been prepared via thiol-ene click reaction. The polymers have good thermal stability. Meanwhile, the results show that they have selective recognition capabilities only for Fe3+, which are mainly manifested as significant quenching of fluorescence and color modulation under visible light. The sensitivity is good, and the limit of detection reaches as low as 0.14 µM. They can also be used as reversible chemical probes to detect Fe3+. Therefore, the click reaction provides us with a facile method for preparing fluorescent polymer probes.

A quinoline-based fluorescent chemosensor for palladium ion (Pd2+)-selective detection in aqueous solution

Quinoline-based fluorescent chemosensors have been extensively developed for various metal cations, but it was still rare for Pd²⁺-selective detection. In this work, a novel quinoline-benzimidazole conjugate containing one carboxylic acid group (QBM) was designed, and the QBM displayed highly selective fluorescence quenching response towards Pd²⁺ over other metal cations in aqueous solution. The fluorescence titration revealed a good linear relationship between the fluorescence intensity and the Pd²⁺ concentration in the range of 0.5-10 μmol L^-1, with the detection limit of 0.26 μmol L^-1 (S/N = 3). Fluorescence detection of Pd²⁺ in practical water sample was also successfully achieved.

Conjugated polymers – a versatile platform for various photophysical, electrochemical and biomedical applications: a comprehensive review

Tuneable properties of conjugated polymers are attractive for use in multiple domains like optical, electronic and biological applications.