Preparation Of Fluorescent Probes Research Articles

Fabrication of chitosan-based fluorescent hydrogel membranes cross-linked with bisbenzaldehyde for efficient selective detection and adsorption of Fe2+

Chitosan, as a natural biomass material, is green, recyclable, sustainable and well biocompatible. The molecular chain is rich in active groups such as amino and hydroxyl groups, and its preparation of fluorescent probes has the advantages of biocompatibility and efficient detection performance. In this study, a bis(benzaldehyde) (BHD) fluorescent functional molecule was designed. Then a series of fluorescent chitosan-based hydrogel films (CSBHD) were prepared using chitosan as raw material and BHD as cross-linking agent. As a fluorescent probe for metal ions, CSBHD was able to efficiently detect Fe2+ with a linear correlation of fluorescence intensity in the range of 0–160 μM, and the limit of detection (LOD) was 0.55 μM. Moreover, it has excellent adsorption performance for Fe2+ ions, with a maximum adsorption capacity of 223.5 g/mg at 500 mg/L Fe2+ concentration. Finally, we characterised the structure and microscopic morphology of CSBHD films and found that CSBHD as a hydrogel film has a high cross-linking density, good water resistance, excellent thermal stability, strong resistance to swelling, and excellent stability in cycling tests. Hence, it has great potential for application in adsorption and detection of Fe2+ ions. It also provides a good strategy for the application of chitosan based fluorescent probe materials in environmental monitoring and heavy metal ion adsorption.

Co‐aggregation as A Simple Strategy for Preparing Fluorogenic Tetrazine Probes with On‐Demand Fluorogen Selection**

AbstractLife science has progressed with applications of fluorescent probes—fluorophores linked to functional units responding to biological events. To meet the varied demands across experiments, simple organic reactions to connect fluorophores and functional units have been developed, enabling the on‐demand selection of fluorophore‐functional unit combinations. However, organic synthesis requires professional equipment and skills, standing as a daunting task for life scientists. In this study, we present a simple, fast, and convenient strategy for probe preparation: co‐aggregation of hydrophobic molecules. We focused on tetrazine—a difficult‐to‐prepare yet useful functional unit that provides effective bioorthogonal reactivity and strong fluorogenicity. Simply mixing the tetrazine molecules and aggregation‐induced emission (AIE) luminogens in water, co‐aggregation is induced, and the emission of AIE luminogens is quenched. Subsequent click reaction bioorthogonally turns on the emission, identifying these coaggregates as fluorogenic probes. Thanks to this bioorthogonal fluorogenicity, we established a new time‐gated fluorescence bioimaging technique to distinguish overlapping emission signals, enabling multi‐organelle imaging with two same‐color fluorophores. Our study showcases the potential of this co‐aggregation method for the on‐demand preparation of fluorescent probes as well as protocols and molecular design principles in this approach, offering an effective solution to evolving needs in life science research.

The creation of immunofluorescence probes based on monoclonal antibodies series ICO and phycoerythrin - fluorophore of phycobiliprotein group for analysis of cell populations by flow cytometry

Introduction . Fluorescent probes based on monoclonal antibodies (MAb) are widely used in scientific and clinical research in the field of oncology, hematology, immunology, epidemiology. The unique spectral properties of the natural protein, phycoerythrin (PE), made it the dominant dye widely used for the preparation of fluorescent probes based on MAb. Objective . To create of fluorescent probes based on the MAb and the fluorescent dye PE by two alternative methods of protein synthesis. Materials and methods . MAb to T lymphocyte antigen (clone ICO-86, clone ICO-31), fluorescent dye PE and bifunctional agents SPDP and SMCC were used in the work. Liquid chromatography methods were used for isolation and purification of MAb: in the first step, affinity isolation of immunoglobulins on the immobilized protein G or anion exchange column chromatography. Gelfiltration on a PD-10 column was used to purify the conjugates (immunofluorescent probes, IFP) in the second step, the concentration and labeling density of the IFP were determined spectrophotometrically. Results . Conjugation of MAb with PE was carried out at a molar ratio of components of 1: 2. For this both components of the conjugation reaction (PE and MAb) were separately modified. For the creation of IFP on the basis of the MAb of the ICO series, both methods of conjugation of Mab with PE are applicable, but method II, in which the chemical modification by the bifunctional SMCC agent is exposed only to the PE molecule by its free amino groups, and the immunoglobulin molecule is conserved in the maximally native state is preferred. Conclusion . The methods described in the article allow to obtain immunofluorescent probes based on antibodies of the ICO series that are comparable in their analytical characteristics to foreign commercial analogs.

Synthesis and structure of 2-substituted pyrene-derived scaffolds

Pyrenes bear a propensity to form fluorescent excimers, and thus this chromophore is often found in sensors and fluorescent probes. 2-Functionalized pyrenes are of particular interest, however the preparation of these scaffolds is not trivial, involving synthetic routes that require 4,5,9,10-tetrahydropyrene as a key intermediate. Herein, the development and optimization of routes for the synthesis of 2-functionalized pyrene-derived building blocks, with potential to be used as tags in the preparation of fluorescent probes, is described. Additionally, the crystal structures of ethyl 4,5,9,10-tetrahydro-2-pyrene-5-oxopentanoate and 2-acetyl-4,5,9,10-tetrahydropyrene revealed distinct conformations of the saturated tetrahydropyrene rings.