Tuning the Emission of Bis-ethylenedioxythiophene-thiophenes upon Aggregation.

The ability of small lipophilic molecules to penetrate the blood-brain barrier through transmembrane diffusion has enabled researchers to explore new diagnostics and therapies for brain disorders. Until now, therapies targeting the brain have mainly relied on biochemical mechanisms, while electrical treatments such as deep brain stimulation often require invasive procedures. An alternative to implanting deep brain stimulation probes could involve administering small molecule precursors intravenously, capable of crossing the blood-brain barrier, and initiating the formation of conductive polymer networks in the brain through in vivo polymerization. This study examines the aggregation behavior of five water-soluble conducting polymer precursors sharing the same conjugate core but differing in side chains, using spectroscopy and various computational chemistry tools. Our findings highlight the significant impact of side chain composition on both aggregation and spectroscopic response.

Self-Assembly of Chiro-Optical Materials from Nonchiral Oligothiophene-Porphyrin Derivatives and Random Coil Synthetic Peptides.

Biomimetic chiral optoelectronic materials can be utilized in electronic devices, biosensors and artificial enzymes. Herein, this work reports the chiro-optical properties and architectural arrangement of optoelectronic materials generated from self-assembly of initially nonchiral oligothiophene-porphyrin derivatives and random coil synthetic peptides. The photo-physical- and structural properties of the materials were assessed by absorption-, fluorescence- and circular dichroism spectroscopy, as well as dynamic light scattering, scanning electron microscopy and theoretical calculations. The materials display a three-dimensional ordered helical structure and optical activity that are observed due to an induced chirality of the optoelectronic element upon interaction with the peptide. Both these properties are influenced by the chemical composition of the oligothiophene-porphyrin derivative, as well as the peptide sequence. We foresee that our findings will aid in developing self-assembled optoelectronic materials with dynamic architectonical accuracies, as well as offer the possibility to generate the next generation of materials for a variety of bioelectronic applications.

Synthesis and Characterization of Oligothiophene-Porphyrin-Based Molecules That Can Be Utilized for Optical Assignment of Aggregated Amyloid-ß Morphotypes.

Molecular tools for fluorescent imaging of protein aggregates are essential for understanding the significance of these pathological hallmarks in proteopathic neurodegenerative diseases, such as Alzheimer's disease. Here, we report the synthesis of a series of oligothiophene porphyrin hybrids, OTPHs, and the evaluation of these dyes for fluorescent imaging of beta-amyloid aggregates in tissue sections from a transgenic mouse model with Alzheimer's disease pathology. The OTPHs proved to be successful for spectral and lifetime imaging assessment of protein deposits and our findings confirm that the enhanced spectral range and distinct lifetime diversity of these novel tools allow a more precise assessment of heterogeneous amyloid morphology compared with the corresponding oligothiophene dye. In addition, the chemical identity of the porphyrin moiety, as well as the spacing between the two optical active moieties, influenced the OTPHs performance for fluorescent assignment of the protein deposits. We foresee that our findings will aid in the chemical design of dyes that can be utilized as optical tools for studying the polymorphic nature of protein aggregates associated with proteopathic neurodegenerative diseases.

Synthesis and Characterization of Novel Fluoro-glycosylated Porphyrins that can be Utilized as Theranostic Agents.

Invited for this month's cover picture is the group of Professor Peter Nilsson at the Department of Physics, Chemistry and Biology at Linköping University (Sweden). The cover picture shows a fluoro-glycoporphyrin that selectively targets cancer cells. The selectivity towards cancer cells are afforded due to proper functionalization of the porphyrin scaffold with specific carbohydrates, and the cancer cells can be visualized because of the intrinsic fluorescence from the porphyrin. The molecule also exhibits properties for photodynamic therapy and the incorporation of fluorine, in the form of 2-fluoro-2-deoxy glucose (FDG), offers the possibility to apply these compounds as 18F positron emission tomography (PET) tracers. Thus, fluoro-glycoporphyrins display multimodal properties and can be employed as theranostic agents targeting cancer cells. Read the full text of their Full Paper at https://doi.org/10.1002/open.201800020.

Synthesis and Characterization of Novel Fluoro-glycosylated Porphyrins that can be Utilized as Theranostic Agents.

Small molecules with modalities for a variety of imaging techniques as well as therapeutic activity are essential, as such molecules render opportunities to simultaneously conduct diagnosis and targeted therapy, so called theranostics. In this regard, glycoporphyrins have proven useful as theranostic agents towards cancer, as well as noncancerous conditions. Herein, the synthesis and characterization of heterobifunctional glycoconjugated porphyrins with two different sugar moieties, a common monosaccharide at three sites, and a 2-fluoro-2-deoxy glucose (FDG) moiety at the fourth site are presented. The fluoro-glycoconjugated porphyrins exhibit properties for multimodal imaging and photodynamic therapy, as well as specificity towards cancer cells. We foresee that our findings might aid in the chemical design of heterobifunctional glycoconjugated porphyrins that could be utilized as theranostic agents.

Enhanced fluorescent assignment of protein aggregates by an oligothiophene-porphyrin-based amyloid ligand.

Fluorescent probes identifying protein aggregates are of great interest, as deposition of aggregated proteins is associated with many devastating diseases. Here, we report that a fluorescent amyloid ligand composed of two distinct molecular moieties, an amyloidophilic pentameric oligothiophene and a porphyrin, can be utilized for spectral and lifetime imaging assessment of recombinant Aß 1-42 amyloid fibrils and Aß deposits in brain tissue sections from a transgenic mouse model with Alzheimer's disease pathology. The enhanced spectral range and distinct lifetime diversity of this novel oligothiophene-porphyrin-based ligand allow a more precise assessment of heterogeneous amyloid morphology compared with the corresponding oligothiophene dye.