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In this work, we describe the application of the self-assembled europium complex 1 :Eu(III) (where 1 : diethyl 8-methoxy-2-oxo-1,2,4,5-tetrahydro-cyclopenta[ de ]quinolin-3-yl)phosphonate) for the analysis of water content of wheat flour. The methodology herein described represents a robust and accurate way for the detection of small amounts of water in food, providing comparing results with well-established methods such as thermogravimetry and Karl-Fischer titration. Interestingly, as an advantage over other methods, our luminescence-based approach can be implemented in lab-on-a-chip microfluidic devices for real-time and on-line detection of water content of food samples. Additionally, the remarkably long luminescence lifetime of Eu(III) allows the use of state-of-the-art imaging strategies based on PLIM microscopy for the direct visualization of unique water content maps of wheat flour particles. [Display omitted] • Self-assembled europium complex 1 :Eu(III) detects water in wheat flour with accuracy. • Robust method provides comparable results to established techniques. • Luminescence-based approach is advantageous as it can be implemented in lab-on-a-chip devices for real-time detection. • The long luminescence lifetime of Eu(III) allows visualization of water content maps via PLIM microscopy. [ABSTRACT FROM AUTHOR]

[Display omitted] • 9-Amino-quinolimide based fluorescent labelling reagents have been prepared. • 9-Amino-quinolimide-labelled peptides derived from CDK5 have been obtained. • CDK5 labelled peptides behave as p25 fluorescence sensors in vitro and in cellulo. • In cellulo imaging FRET response to a CDK5 labelled peptide correlates with p25 level. CDK5 kinase is activated through interactions with different partners including the p35/p25 regulators. Active CDK5 plays a key role in several neuronal functions and its hyperactivity contributes to a variety of neurodegenerative processes and several human cancers, in particular glioblastomas and neuroblastomas. In order to probe partners that interact with CDK5, we designed and synthesized fluorescent quinolimide-labelled peptides derived from the C-helix of CDK5, which were implemented to probe CDK5 partners in vitro and by in cellulo imaging in U87 glioblastoma and N2a neuroblastoma cells. Ectopic expression of a NIR fluorescent protein miRFP670 fusion with p25 (p25-miRFP670) in N2a cells induced FRET between a quinolimide-labelled peptide biosensor and p25-miRFP670, and fluorescence intensity was proportional to the expression level of p25, thereby demonstrating the potential of the quinolimide-labelled peptide biosensor to report on p25 relative abundance. [ABSTRACT FROM AUTHOR]

The presence of neuritic plaques and amyloid fibrils arising from the misfolding of certain proteins is the principal molecular indicator of neurodegenerative diseases such as Alzheimer's and Parkinson's disease. Methodologies for studying the early stages of amyloid aggregation are rapidly arising to provide a better understanding of the mechanism of fibrillization and cytotoxicity and to identify potential targets for diagnosis and therapy. The method presented here involves the simultaneous use of two different fluorophores, a quinolimide derivative and Nile Blue A. These are capable of interacting with and reporting on the formation of preamyloid aggregates and fibrils of apoferritin through fluorescence resonance energy transfer (FRET), which occurs between them, thus maximizing the contrast in detection and quantitative information of such amyloid species by using multidimensional fluorescence lifetime imaging microscopy (FLIM). • A pair of dyes interact with pre-amyloid aggregates with different affinities. • FRET between the dyes allow sensitive detection of different types of aggregates. • The aggregates are characterized by multiparametric FLIM and superresolution STED microscopies. [ABSTRACT FROM AUTHOR]