| 1. |
- Björk, Linnea, et al.
(författare)
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Proteophenes - Amino Acid Functionalized Thiophene-based Fluorescent Ligands for Visualization of Protein Deposits in Tissue Sections with Alzheimers Disease Pathology
- 2022
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Ingår i: Chemistry - A European Journal. - : Wiley-V C H Verlag GMBH. - 0947-6539 .- 1521-3765. ; 28:62
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Tidskriftsartikel (refereegranskat)abstract
- Protein deposits composed of specific proteins or peptides are associated with several neurodegenerative diseases and fluorescent ligands able to detect these pathological hallmarks are vital. Here, we report the synthesis of a class of thiophene-based ligands, denoted proteophenes, with different amino acid side-chain functionalities along the conjugated backbone, which display selectivity towards specific disease-associated protein aggregates in tissue sections with Alzheimers disease (AD) pathology. The selectivity of the ligands towards AD associated pathological hallmarks, such as aggregates of the amyloid-beta (A beta) peptide or tau filamentous inclusions, was highly dependent on the chemical nature of the amino acid functionality, as well as on the location of the functionality along the pentameric thiophene backbone. Finally, the concept of synthesizing donor-acceptor-donor proteophenes with distinct photophysical properties was shown. Our findings provide the structural and functional basis for the development of new thiophene-based ligands that can be utilized for optical assignment of different aggregated proteinaceous species in tissue sections.
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| 2. |
- Butina, Karen, et al.
(författare)
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Structural Properties Dictating Selective Optotracer Detection of Staphylococcus aureus
- 2022
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Ingår i: ChemBioChem. - : Wiley. - 1439-4227 .- 1439-7633. ; 23:11
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Tidskriftsartikel (refereegranskat)abstract
- Optotracers are conformation-sensitive fluorescent tracer molecules that detect peptide- and carbohydrate-based biopolymers. Their binding to bacterial cell walls allows selective detection and visualisation of Staphylococcus aureus (S. aureus). Here, we investigated the structural properties providing optimal detection of S. aureus. We quantified spectral shifts and fluorescence intensity in mixes of bacteria and optotracers, using automatic peak analysis, cross-correlation, and area-under-curve analysis. We found that the length of the conjugated backbone and the number of charged groups, but not their distribution, are important factors for selective detection of S. aureus. The photophysical properties of optotracers were greatly improved by incorporating a donor-acceptor-donor (D-A-D)-type motif in the conjugated backbone. With significantly reduced background and binding-induced on-switch of fluorescence, these optotracers enabled real-time recordings of S. aureus growth. Collectively, this demonstrates that chemical structure and photophysics are key tunable characteristics in the development of optotracers for selective detection of bacterial species.
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| 3. |
- Lantz, Linda, 1985-
(författare)
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Synthesis of donor–acceptor–donor thiophene based ligands that can be utilized for optical assignment of pathological targets
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Thiophene based ligands represent a class of molecular reporters proven superior in discerning pathological targets involved in neurodegenerative diseases, as well as bacterial infection. By fluorometric detection that depends on the milieu surrounding the ligand these biological processes can be studied with fluorescence spectroscopy and hyper-spectral confocal microscopy. The binding of a thiophene-based ligand to a biological target can entail specific fluorescent read-out through the conformation-sensitive ligand. Thus, the photo-physical properties of these molecules and the optical connection of binding make them valuable tools in the study of pathological events. As optical detection of pathological phenomena can be realized through several fluorescence parameters, including changes in fluorescent intensity, wavelength shifts, energy transfer, or emission lifetime, molecular studies of pathological targets in several biological systems have been realized by employing thiophene-based ligands. For instance, utilization of conjugated polydisperse and monodisperse thiophene-based molecules has in several studies demonstrated detection of disease associated protein aggregates in vitro, ex vivo and in vivo. My doctoral studies have included the synthesis and characterization of thiophene based donor-acceptor-donor (D–A–D) molecules and evaluation of how changes in side-chain positions, molecular length and number of negatively charged carboxylates impact interaction with biological targets. This thesis describes the utilization of the D–A–D molecules as fluorescent ligands for protein aggregates associated with Alzheimer’s disease and optical assignment of specific bacteria. The design and synthesis of these novel D–A–D thiophene-based fluorophores, with alterations in back bone, distribution of side chains and negatively charged groups, have generated novel insights regarding the ligands chemical structure on ligand performance, by the assessment of binding mode of the respective ligand to distinct pathological entities. Furthermore, the D–A–D molecules hold alternative photo-physical properties compared to thiophene-based ligand and these optical properties of the ligands have been employed to provide new insights in questions regarding protein aggregate polymorphism in Alzheimer’s disease. Overall, by organic synthesis we have fine-tuned the properties of thiophene-based D-A-D molecules and evaluated how modifications affect interactions with distinct biological, pathological targets and we foresee that D–A–D thiophene-based ligands will expand the toolbox for studying pathological targets in neurodegenerative diseases, as well as bacterial infection.
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