Proof of concept of using a membrane-sensing peptide for sEVs affinity-based isolation.

One main limitation in biomarker studies using EVs is the lack of a suitable isolation method rendering high yield and purity samples in a quick and easily standardized procedure. Here we report an affinity isolation method with a membrane-sensing peptide (MSP) derived from bradykinin. We designed a protocol based on agarose beads carrying cation chelates to specifically bind to the 6His-tagged membrane-sensing peptide.

Membrane-Sensing Peptides for Extracellular Vesicle Analysis.

Analytical platforms for small extracellular vesicle (sEV) high-throughput analysis are highly desirable. These bionanoparticles present fairly distinctive lipid membrane features including high curvature, lipid-packing defects, and a relative abundance in lipids. sEV membrane could be considered as a "universal" marker, complementary or alternative to traditional surface-associated proteins.

Epitope Mapping on Microarrays Highlights a Sequence on the N Protein with Strong Immune Response in SARS-CoV-2 Patients.

In SARS-CoV-2 pandemic scenario, the identification of rapid methods to detect antibodies against coronavirus has been a wide and urgent issue. Epitope mapping on peptide microarrays is a rapid way to identify sequences with a high immunoreactivity. The process begins with a proteome-wide screening, based on immune affinity; the use of a high-density microarray is followed by a validation phase, where a restricted panel of probes is tested using peptide microarrays; peptide sequences are immobilized through a click-based strategy.

Hybrid Peptide-Agarose Hydrogels for 3D Immunoassays.

Recent advances in biosensing analytical platforms have brought relevant outcomes for novel diagnostic and therapy-oriented applications. In this context, 3D droplet microarrays, where hydrogels are used as matrices to stably entrap biomolecules onto analytical surfaces, potentially provide relevant advantages over conventional 2D assays, such as increased loading capacity, lower nonspecific binding, and enhanced signal-to-noise ratio. Here, we describe a hybrid hydrogel composed of a self-assembling peptide and commercial agarose (AG) as a suitable matrix for 3D microarray bioassays.

Comparing digital detection platforms in high sensitivity immune-phenotyping of extracellular vesicles.

Despite their clinical potential, Extracellular Vesicles (EVs) struggle to take the scene as a preeminent source of biomarkers in liquid biopsy. Limitations in the use of EVs origin from their inherent complexity and heterogeneity and from the sensitivity demand in detecting low to very low abundant disease-specific sub-populations. Such need can be met by digital detection, namely capable to reach the single-molecule sensitivity.

Composite Peptide-Agarose Hydrogels for Robust and High-Sensitivity 3D Immunoassays.

Canonical immunoassays rely on highly sensitive and specific capturing of circulating biomarkers by interacting biomolecular baits. In this frame, bioprobe immobilization in spatially discrete three-dimensional (3D) spots onto analytical surfaces by hydrogel encapsulation was shown to provide relevant advantages over conventional two-dimensional (2D) platforms. Yet, the broad application of 3D systems is still hampered by hurdles in matching their straightforward fabrication with optimal functional properties.

Self-Assembling Peptide Hydrogels for 3D Microarrays.

Recent advances in biosensing analytical platforms have brought relevant outcomes for novel diagnostic and therapy-oriented applications. In this context, hydrogels have emerged as appealing matrices to locally confine biomolecules onto sensing surfaces under solution mimetic conditions, preserving their structural integrity and function. Here, we describe the application of a self-assembling peptide hydrogel as a suitable matrix for 3D microarray bioassays.

Membrane-binding peptides for extracellular vesicles on-chip analysis.

Small extracellular vesicles (sEVs) present fairly distinctive lipid membrane features in the extracellular environment. These include high curvature, lipid-packing defects and a relative abundance in lipids such as phosphatidylserine and ceramide. sEV membrane could be then considered as a "universal" marker, alternative or complementary to traditional, characteristic, surface-associated proteins.

Chemical Perturbation of Oncogenic Protein Folding: from the Prediction of Locally Unstable Structures to the Design of Disruptors of Hsp90-Client Interactions.

Protein folding quality control in cells requires the activity of a class of proteins known as molecular chaperones. Heat shock protein-90 (Hsp90), a multidomain ATP driven molecular machine, is a prime representative of this family of proteins. Interactions between Hsp90, its co-chaperones, and client proteins have been shown to be important in facilitating the correct folding and activation of clients.

Clickable cellulosic surfaces for peptide-based bioassays.

The use of peptides in paper-based analytics is a highly appealing field, yet it suffers from severe limitations. This is mostly due to the loss of effective target recognition properties of this relatively small probes upon nonspecific adsorption onto cellulose substrates. Here we address this issue by introducing a simple polymer-based strategy to obtain clickable cellulose surfaces, that we exploited for the chemoselective bioconjugation of peptide bioprobes.

Acid Catalyzed Formation of C⁻C and C⁻S Bonds via Excited State Proton Transfer.

The behavior of 2-naphthol and 7-bromo-2-naphthol as organic photoacids are exploited in organic synthesis for the preparation of benzyl sulfides (using a trichloroacetimidate derivative as the starting substrate) and polycyclic amines via acid catalyzed condensation of 1,2,3,4-tetrahydroisoquinoline with aldehydes.