Diagnostics of Multiple Sclerosis (MS) are essentially based on the gold standard magnetic resonance imaging. Few alternative simple assays are available to follow up disease activity. Considering that the disease can remain elusive for years, identification of antibodies fluctuating in biological fluids as relevant biomarkers of immune response is a challenge. In previous studies, we reported that anti-N-glucosylated (N-Glc) peptide antibodies that can be easily detected in Solid-Phase Enzyme-Linked ImmunoSorbent Assays (SP-ELISA) on MS patients’ sera preferentially recognize hyperglucosylated adhesin of non-typeable Haemophilus Influenzae. Since multivalency can be useful for diagnostic purposes to allow an efficient coating in ELISA, we report herein the development of a collection of Multiple N-glucosylated Peptide Epitopes (N-Glc MEPs) to detect anti-N-Glc antibodies in MS. To this aim, a series of N-Glc peptide antigens to be represented in the N-GlcMEPs were tested in competitive ELISA. We confirmed that the epitope recognized by antibodies shall contain at least 5-mer sequences including the fundamental N-Glc moiety. Using a 4-branched dendrimeric lysine scaffold, we selected the N-Glc MEP 24, carrying the minimal epitope Asn(Glc) anchored to a polyethylene glycol-based spacer (PEG) containing a 19-atoms chain, as an efficient multivalent probe to reveal specific and high affinity anti-N-Glc antibodies in MS.

This Letter reports on the processing, mechanical properties, electrochemical performance, and toxicity behavior of a multiprincipal element Ti35Nb30Zr29Mo3Ta3 alloy. The recovered centimeter-sized cubes or parallelepipeds were polished before analysis. It was found that the homogeneity and yield stress of the alloys get increased when higher volumetric energy densities are applied during processing. The synthesized alloys also exhibited a Young modulus closer to those of bones than those usually reported on the conventional orthopedic metals (60–80 GPa for this alloy against 110 and 4–30 GPa for the Ti-6Al-4V and bone, respectively). The electrochemical corrosion assays performed at 25 and 37 °C, in sodium chloride (NaCl, 0.1 M), deoxygenated high glucose Dulbecco's Modified Eagle Medium (DMEM), and deoxygenated DMEM implemented with fetal bovine serum showed corrosion potentials (Ecorr) ranged in the order NaCl(25 °C) ≈ DMEM + PBS(37 °C) > DMEM(37 °C) and impedances much larger in the DMEM and DMEM + PBS media than in NaCl. Finally, pre-osteoblasts cells cultured in the medium conditioned by the alloy did not evidence cytotoxicity effect, because no effects on the cell proliferation and morphology were observed. These data suggest the biocompatibility of this alloy, indicating no acute toxicity, which is a prerequisite for the integration of an alloy as a bioimplant.

Surface functionalization with biological molecules, such as peptides or proteins, is a very promising method for developing new biomaterials with many potential applications. However, due to their chemical complexity, the characterization of biological materials is often a very challenging task. In this context, time-of-flight secondary ion mass spectrometry is a very helpful characterization tool due to its ability to provide very detailed spatially resolved chemical information of the topmost layer. The peculiar emission/ion formation mechanisms involved in ToF-SIMS analysis often do not allow the detection of the molecular ion of proteins and peptides, providing a rich fragmentation pattern, which is difficult to be related to the surface composition using a univariate approach, due to the relevant number of peaks in the SIMS spectra of peptides and proteins and the slight differences in intensities between different samples. Therefore, we used multivariate analysis to extract the information contained in the ToF-SIMS spectra of four peptides with high amino acid sequence similarity along the peptide chain. The reference peptide (TAT1) is a 12-unit sequence of six amino acids (GRKKRRQRRRPS). The other three peptides have been obtained by inserting a bAla-H dipeptide (carnosine) in three different positions inside the TAT1 chain, namely, GRKKRRQRRRPS-bAla-H (TAT1-Car), bAla-HGRKKRRQRRRPS (Car-TAT1), and GRKKRRQ-bAla-H-RRRPS (T-Car-T). We show that these peptides can be distinguished by ToF-SIMS combined with multivariate data analysis.

Redox unbalance, a molecular trait common to neurodegenerative conditions and para-physiological processes like aging, is a critical factor in disease development and in exacerbating progression. The mechanism by which redox imbalance perturbs cellular homeostasis is strongly linked to the activity and function of the ubiquitin–proteasome system (UPS). The UPS, along with autophagy, is the primary intracellular proteolytic system, regulating targeted proteolysis and removing damaged proteins. Consequently, the UPS serves also as the first line of defense for cellular recovery following exposure to redox stressors. Paradoxically, the composition and function of the UPS can also be negatively targeted by redox unbalance through a vicious cycle. The alterations in redox balance and UPS biological mechanisms are involved in the etiopathogenesis of chronic eye disorders. These disorders encompass a diverse repertoire of pathologies affecting the retinal layers (e.g., age-related macular degeneration, diabetic retinopathy) and the optic nerve (e.g., glaucoma). Nowadays, the comprehension of the interplay between proteostasis and oxidative redox status remains pivotal for identifying new therapeutic approaches. Encouragingly, a number of anti-oxidant compounds have been reported to modulate proteasome activity against redox insults in vitro and in vivo. Furthermore, these compounds provide cytoprotective roles in both in vitro and animal models of eye diseases. Therefore, this review highlights recent research on the interplay of the UPS with oxidative stress in physio-pathological conditions, focusing on the onset and progression of ocular diseases, thereby providing new insights into UPS-oxidative stress interaction.

NH₂ decorated intrinsically photoluminescent hydrogels (IPH-NH₂) were functionalized with the addition of various peptides via EDC/NHS coupling method. These peptidic devices bind copper with binding affinities depending on surface functionalization. Particularly, fluorescence analysis of copper titrations, alongside the determination of quenching efficiency and lifetime measurements, allowed to assess binding constants and to elucidate the underlying binding mechanism. Various peptides, having the same copper binding amino acidic residues (GHK) but different chain lengths, were tested and it was found that increasing the distance of the GHK sequence from the IPH-NH₂ surface resulted in a decrease in the binding constant, as well as a reduction in quenching efficiency, whereas the binding mechanism remained unchanged as indicated by lifetime measurements. This method not only provides binding constants for peptides immobilized on biosensor surfaces or pre-fabricated devices without altering their structure, but also contributes to the optimization of biosensor design, tailoring it to its intended application.