Assessing the Quality of Solvent-Assisted Lipid Bilayers Formed at Different Phases and Aqueous Buffer Media: A QCM-D Study.

Supported lipid bilayers (SLBs) are low-complexity biomimetic membranes, serving as popular experimental platforms to study membrane organization and lipid transfer, membrane uptake of nanoparticles and biomolecules, and many other processes. Quartz crystal microbalance with dissipation monitoring has been utilized to probe the influence of several parameters on the quality of SLBs formed on Au- and SiO-coated sensors. The influence of the aqueous medium (i.

Spontaneous nanotube formation of an asymmetric glycolipid.

Over the past decades, advances in lipid nanotechnology have shown that self-assembled lipid structures providing ease of preparation, chemical stability, and biocompatibility represent a landmark on the development of multidisciplinary technologies. Lipid nanotubes (LNTs) are a unique class of lipid self-assembled structures, bearing unique properties such as high-aspect ratio, tunable diameter size, and precise molecular recognition. They can be obtained either by the action of external factors to already formed vesicles or spontaneously, the latter depending strongly on subtle molecular features.

Photo-Oxidizing Ruthenium(II) Complexes with Enhanced Visible-Light Absorption and G-quadruplex DNA Binding Abilities.

Photosensitizers that gather high photo-oxidizing power and strong visible-light absorption are of great interest in the development of new photo-chemotherapeutics. Indeed, such compounds constitute attractive candidates for the design of type I photosensitizers that are not dependent on the presence of oxygen. In this paper, we report on the synthesis and studies of new ruthenium(II) complexes that display strong visible-light absorption and can oxidize guanine residues under visible-light irradiation, as evidenced by nanosecond transient absorption spectroscopy.

Molecularly Imprinted Polymer Nanoparticles Enable Rapid, Reliable, and Robust Point-of-Care Thermal Detection of SARS-CoV-2.

Rapid antigen tests are currently used for population screening of COVID-19. However, they lack sensitivity and utilize antibodies as receptors, which can only function in narrow temperature and pH ranges. Consequently, molecularly imprinted polymer nanoparticles (nanoMIPs) are synthetized with a fast (2 h) and scalable process using merely a tiny SARS-CoV-2 fragment (∼10 amino acids).

Asymmetric Lipid Transfer between Zwitterionic Vesicles by Nanoviscosity Measurements.

The interest in nano-sized lipid vesicles in nano-biotechnology relies on their use as mimics for endosomes, exosomes, and nanocarriers for drug delivery. The interactions between nanoscale size lipid vesicles and cell membranes involve spontaneous interbilayer lipid transfer by several mechanisms, such as monomer transfer or hemifusion. Experimental approaches toward monitoring lipid transfer between nanoscale-sized vesicles typically consist of transfer assays by fluorescence microscopy requiring the use of labels or calorimetric measurements, which in turn require a large amount of sample.

Determination of the Rituximab Binding Site to the CD20 Epitope Using SPOT Synthesis and Surface Plasmon Resonance Analyses.

Antibodies not only play a major role in clinical diagnostics and biopharmaceutical analysis but also are a class of drugs that are regularly used to treat numerous diseases. The identification of antibody-epitope binding sites is then of great interest to many emerging medical and bioanalytical applications, particularly to design monoclonal antibodies (mAb) mimics taking advantage of amino acid residues involved in the binding. Among relevant antibodies, the monoclonal antibody rituximab has received significant attention as it is exploited to treat several cancers including non-Hodgkin's lymphoma and chronic lymphocytic leukemia, as well as some autoimmune disorders such as rheumatoid arthritis.

Impact of Antigen Density on Recognition by Monoclonal Antibodies.

Understanding antigen-antibody interactions is important to many emerging medical and bioanalytical applications. In particular, the levels of antigen expression at the cell surface may determine antibody-mediated cell death. This parameter has a clear effect on outcome in patients undergoing immunotherapy.

The pK value of the proximal water molecule trans to a high-valent Mn[double bond, length as m-dash]O porphyrin: towards the control of reactivity by pH.

The high-valent manganese-oxo species of Mn-TMPyP4 porphyrin interacts in the minor grooves of AT-rich regions of DNA and mediates hydroxylation of C-H bonds of deoxyribose leading to DNA break. The reaction was observed at different pHs. It is shown that the hydroxylation was not efficient at low pH (pH 6) while it worked well at higher pH (pH 8).

New Ruthenium-Based Probes for Selective G-Quadruplex Targeting.

Telomeric regions containing G-quadruplex (G4) structures play a pivotal role in the development of cancers. The development of specific binders for G4s is thus of great interest in order to gain a deeper understanding of the role of these structures, and to ultimately develop new anticancer drug candidates. For several years, Ru complexes have been studied as efficient probes for DNA.

Template-Mediated Stabilization of a DNA G-Quadruplex formed in the HIV-1 Promoter and Comparative Binding Studies.

G-rich DNA oligonucleotides derived from the promoter region of the HIV-1 long terminal repeat (LTR) were assembled onto an addressable cyclopeptide platform through sequential oxime ligation, a thiol-iodoacetamide SN2 reaction, and copper-catalyzed azide-alkyne cycloaddition reactions. The resulting conjugate was shown to fold into a highly stable antiparallel G4 architecture as demonstrated by UV, circular dichroism (CD), and NMR spectroscopic analysis. The binding affinities of six state-of-the-art G4-binding ligands toward the HIV-G4 structure were compared to those obtained with a telomeric G4 structure and a hairpin structure.