Raman spectroscopy reveals biochemical differences in plasma derived extracellular vesicles from sporadic Amyotrophic Lateral Sclerosis patients.

Sporadic amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease for which there is no validated blood based biomarker. Extracellular vesicles (EVs) have the potential to solve this unmet clinical need. However, due to their heterogeneity and complex chemical composition, EVs are difficult to study. Raman spectroscopy (RS) is an optical method that seems particularly well suited to address this task. In fact, RS provides an overview of the biochemical composition of EVs quickly and virtually without any sample preparation. In this work, we studied by RS small extracellular vesicles (sEVs), large extracellular vesicles (lEVs) and blood plasma of sporadic ALS patients and of a matched cohort of healthy controls. The obtained results highlighted lEVs as a particularly promising biomarker for ALS. In fact, their Raman spectra show that sporadic ALS patients have a different lipid content and less intense bands relative to the aromatic amino acid phenylalanine.

A self-assembling peptide hydrogel for ultrarapid 3D bioassays.

Biosensing analytical platforms rely on the intimate structure-function relationship of immobilized probes. In this context, hydrogels are appealing semi-wet systems to locally confine biomolecules while preserving their structural integrity and function. Yet, limitations imposed by biomolecule diffusion rates or fabrication difficulties still hamper their broad application. Here, using a self-assembling peptide, a printable and self-adhesive hydrogel was obtained and applied to fabricate arrays of localized bio-functional 3D microenvironments on analytical interfaces. This soft matrix represents a robust and versatile material, allowing fast and selective tuning of analyte diffusion, which is exploited here to run in-gel immunoassays under solution-like conditions in an unprecedented (<10 min) time frame. The developed material overcomes major limitations associated with hydrogels for bioassays, widening the prospects for easy fabrication of multifunctional bio-interfaces for high-throughput, molecular recognition assays.