Cellular Uptake of Phase-Separating Peptide Coacervates.

Peptide coacervates self-assembling via liquid-liquid phase separation are appealing intracellular delivery vehicles of macromolecular therapeutics (proteins, DNA, mRNA) owing to their non-cytotoxicity, high encapsulation capacity, and efficient cellular uptake. However, the mechanisms by which these viscoelastic droplets cross the cellular membranes remain unknown. Here, using multimodal imaging, data analytics, and biochemical inhibition assays, we identify the key steps by which droplets enter the cell.

Dendronized oligoethylene glycols with phosphonate for cell-repellent coating of oxide surfaces: coarse-scale and nanoscopic interfacial forces.

Dendronized oligoethylene glycols (dendron OEGs) with two phosphonate groups (phosphonate ) have been drawing significant attention as a new class of coating materials for superparamagnetic iron oxide surfaces. However, despite dendron OEGs showing outstanding stability in physiological fluids in previous studies, little is understood about their structure and mechanical properties. Herein we report the surface and internal structures and mechanical properties of dendron OEGs, and quantitatively determine their ability to avoid non-specific adhesion of blood platelets.

Detection of streptavidin-biotin intermediate metastable states at the single-molecule level using high temporal-resolution atomic force microscopy.

Although the streptavidin-biotin intermolecular bond has been extensively used in many applications due to its high binding affinity, its exact nature and interaction mechanism have not been well understood. Several reports from previous studies gave a wide range of results in terms of the system's energy potential landscape because of bypassing some short-lived states in the detection process. We employed a quasi-static process of slowly loading force onto the bond (loading rate = 20 pN s) to minimize the force-induced disruption and to provide a chance to explore the system in near-equilibrium.

Damage-free tip-enhanced Raman spectroscopy for heat-sensitive materials.

We report a method to establish experimental conditions for tip-enhanced Raman spectroscopy (TERS) with low thermal and mechanical damage to samples. In this method, we monitor the thermal desorption of thiol molecules from a gold-coated probe of an atomic force microscope (AFM) via TERS spectra. Temperatures for desorption of thiol molecules (60-100 °C) from gold surfaces cover the temperature range for degradation of heat-sensitive biomaterials (e.