Activity

  • Sigmon Crosby posted an update 10 months, 3 weeks ago

    Extracellular vesicles (EVs) are a potent intercellular communication system. Such small vesicles transport biomolecules between cells and throughout the body, strongly influencing the fate of recipient cells. Due to their specific biological functions they have been proposed as biomarkers for various diseases and as optimal candidates for therapeutic applications. Despite their extreme biological relevance, their mechanisms of interaction with the membranes of recipient cells are still hotly debated. Here, we propose a multiscale investigation based on atomic force microscopy, small angle X-ray scattering, small angle neutron scattering and neutron reflectometry to reveal structure-function correlations of purified EVs in interaction with model membrane systems of variable complex compositions and to spot the role of different membrane phases on the vesicle internalization routes. Our analysis reveals strong interactions of EVs with the model membranes and preferentially with the borders of protruding phase domains. Moreover, we found that upon vesicle breaking on the model membrane surface, the biomolecules carried by/on EVs diffuse with different kinetics rates, in a process distinct from simple fusion. The biophysical platform proposed here has clear implications on the modulation of EV internalization routes by targeting specific domains at the plasma cell membrane and, as a consequence, on EV-based therapies.Nuclear proteins are crucial in cells and are greatly linked to various biological functions. Abnormal expression of nuclear proteins is associated with many diseases ranging from inflammation to cancer. However, it remains challenging to detect nuclear proteins in single cells because of their low abundance and complex subcellular environment. Herein, we report a subcellular-resolved plasmonic immunosandwich assay (srPISA), for probing nucleus-enriched proteins in single living cells with minimal disruption. We demonstrated the specific extraction and ultrasensitive detection capabilities of the srPISA by probing low-copy-number nuclear telomerase in single living cells and further compared the telomerase expression levels in these single cells. Additionally, we showed the subcellular resolving capability of the srPISA by probing the spatial distribution of smad2 in the nucleus and cytoplasm of single living cells. We found that smad2 was expressed both in the nucleus and the cytoplasm, but showed different expression levels. Moreover, smad2 distributed more homogeneously in the nucleus than in the cytoplasm. Finally, the srPISA of nuclear telomerase in cell division strongly verified that the subcellular analytical results obtained by the srPISA are reliable. Overall, the srPISA approach allowed specific extraction and ultrasensitive detection of target low-copy-number proteins at the subcellular level, providing a unique and powerful single cell analysis tool for cell biology studies.Inversion symmetry in the 1T-phase of pristine dichalcogenide monolayer MX2 (M = Ge, Sn; X = S, Se) is broken in their Janus structures, MXY (M = Ge, Sn; X ≠ Y = S, Se), which induces an in-plane piezoelectric coefficient, d22 = 4.09 (2.15) pm V-1 and a shear piezoelectric coefficient, d15 = 7.90 (13.68) pm V-1 in the GeSSe (SnSSe) monolayer. High flexibility arising from the small Young’s modulus (60-70 N m-1) found in these Group-IV(A) Janus monolayers makes them suitable for large-scale strain engineering. Application of 7% uniaxial tensile strain increases d22 and d15 colossally to 267.07 pm V-1 and 702.34 pm V-1, respectively, thereby reaching the level of bulk piezoelectric perovskite materials. When the Janus GeSSe monolayers are stacked to form a van der Waals (vdW) homo-bilayer, d22 lies between 19.87 and 73.26 pm V-1, while d15 falls into the range between 83.01 and 604.34 pm V-1, depending on the stacking order. The chalcogen exchange energies and overall stabilities of the monolayers and bilayers confirm the feasibility of their experimental synthesis. Moreover, hole mobility in the GeSSe monolayer is greater than the electron mobility along its zigzag directions (μe = 883 cm2 V-1 s-1 and μh = 1134 cm2 V-1 s-1). Therefore, the semiconducting, flexible, and piezoelectric Janus GeSSe monolayer and bilayers are immensely promising for futuristic applications in energy harvesting, nanopiezotronic field-effect transistors, atomically thin sensors, shear/torsion actuators, transducers, self-powered circuits in nanorobotics, and electromechanical memory devices, and biomedical and other nanoelectronic applications.Palladium(0) phosphine complexes are of great importance as catalysts in numerous bond formation reactions that involve oxidative addition of substrates. Highly active catalysts with labile ligands are of particular interest but can be challenging to isolate and structurally characterize. We investigate here the synthesis and chemical reactivity of Pd0 complexes that contain geometrically adaptable diferrocenylmercury-bridged diphosphine chelate ligands (L) in combination with a labile dibenzylideneacetone (dba) ligand. The diastereomeric diphosphines 1a (pSpR, meso-isomer) and 1b (pSpS-isomer) differ in the orientation of the ferrocene moieties relative to the central Ph2PC5H3-Hg-C5H3PPh2 bridging entity. PTC-209 BMI-1 inhibitor The structurally distinct trigonal LPd0(dba) complexes 2a (meso) and 2b (pSpS) are obtained upon treatment with Pd(dba)2. A competition reaction reveals that 1b reacts faster than 1a with Pd(dba)2. Unexpectedly, catalytic interconversion of 1a (meso) into 1b (rac) is observed at room temperature in the presence of only catalytic amounts of Pd(dba)2. Both Pd0 complexes, 2a and 2b, readily undergo oxidative addition into the C-Cl bond of CH2Cl2 at moderate temperatures with formation of the square-planar trans-chelate complexes LPdIICl(CH2Cl) (3a, 3b). Kinetic studies reveal a significantly higher reaction rate for the meso-isomer 2a in comparison to (pSpS)-2b.This work explores a new methodology to adsorb a subphthalocyanine molecule (SubPc) on a hybrid lead bromide perovskite crystal structure with the aim of extending its photoresponse into the visible region. This process consists in the preparation of multidimensional 2D-3D perovskites. The use of large organic cations allows the possibility to insert guest molecules in the crystal structure of the perovskite. In this work, layered and 3D materials are obtained modifying the ratio of the organic cations (A/R) in the perovskite structure (RNH3)2An-1BnX3n+1. The present results show that incorporation of metal-free subphthalocyanine in the interlayer space provided by the 2D phase is a valid procedure to enhance the photoresponse of the perovskite solar cells.