Search results for " FLIM"

Phasor-FLIM analysis of Thioflavin T self-quenching in Concanavalin amyloid fibrils

2020

The formation of amyloid structures has traditionally been related to human neurodegenerative pathologies and, in recent years, the interest in these highly stable nanostructures was extended to biomaterial sciences. A common method to monitor amyloid growth is the analysis of Thioflavin T fluorescence. The use of this highly selective dye, diffused worldwide, allows mechanistic studies of supramolecular assemblies also giving back important insight on the structure of these aggregates. Here we present experimental evidence of self-quenching effect of Thioflavin T in presence of amyloid fibrils. A significant reduction of fluorescence lifetime of this dye which is not related to the propert…

TRANSPORTAN 10 INTERACTION WITH GIANT VESICLES: INSERTION EFFECTS AND PORE FORMATION

Transportan 10 (TP10) is a 21 residues peptide that belongs to the family of the antimicrobial and cytolytic or cytotoxic amphipathic peptides. It contains a high proportion of positively charged amino acids (four lysines), no negative charges and the N-terminus that impart it a formal +5 charge at neutral pH.1 This large number of positive charges is an essential feature for the electrostatic interaction of TP10 with microbial and tumoral membranes, which are characherized by a net negative charge and also by a higher fluidity if compared with mammalin ones.2 Here, combining spectroscopic and fluorescence lifetime imaging techniques, we analyse the fate of the multifunctional3-4 TP10 and i…

Highly tunable protein microspheres for drug delivery

2019

It is well-known that protein amyloid aggregation has profound implications in several neurodegenerative diseases. In contrast, a natural role for amyloid structures as protection, adhesion and storage materials in living system is also reported, promoting protein aggregates as an interesting platform for the design of multifunctional biomaterials. Among the broad range of different amyloid structures protein particulates deserve special attention; they are spherical protein aggregates with radius ranging from hundreds of nm to few um which are readily formed in solution at pHs values near the isoelectric point of the protein they are made of. Interestingly, particulate appears to be a gene…

Direct observation of alpha-lactalbumin, adsorption and incorporation into lipid membrane and formation of lipid/protein hybrid structures

2019

The interaction between proteins and membranes is of great interest in biomedical and biotechnological research for its implication in many functional and dysfunctional processes. We present an experimental study on the interaction between model membranes and alpha-lactalbumin (alpha-La). alpha-La is widely studied for both its biological function and its anti-tumoral properties. We use advanced fluorescence microscopy and spectroscopy techniques to characterize alpha-La-membrane mechanisms of interaction and alpha-La-induced modifications of membranes when insertion of partially disordered regions of protein chains in the lipid bilayer is favored. Moreover, using fluorescence lifetime imag…

Phasor-FLIM for a direct investigation of Transportan 10 interactions with model membranes

2023

Transportan 10 (TP10), a short and positive charged peptide, belonging to the family of the cell penetrating peptides has gained increasing attention for its antimicrobial and anticancer activity but also for its applications in drug delivery as it is able to translocate therapeutic molecules in cellular environment. Due to the complexity of the phenomena involved in cellular uptake and following processes, which strongly depend on the membrane lipid composition, structural details of the peptide (e.g., charge, hydrophobicity, steric hindrance) and environmental conditions, it is not easy to understand the general rules governing them. Here, we combine spectroscopic techniques and fluoresce…

Peptide–Membrane Interactions Monitored by Fluorescence Lifetime Imaging: A Study Case of Transportan 10

2021

The interest on detailed analysis of peptide-membrane interactions is of great interest in both fundamental and applied sciences as these may relate to both functional and pathogenic events. Such interactions are highly dynamic and spatially heterogeneous, making the investigation of the associated phenomena highly complex. The specific properties of membranes and peptide structural details, together with environmental conditions, may determine different events at the membrane interface, which will drive the fate of the peptide-membrane system. Here, we use an experimental approach based on the combination of spectroscopy and fluorescence microscopy methods to characterize the interactions …