Detachment of giant liposomes - coupling of receptor mobility and membrane shape

One-Step Preparation of Magnetic Lipid Bubbles: Magnetothermal Effect Induces the Simultaneous Formation of Gas Nuclei and Self-Assembly of Phospholipids

In recent years, enveloped micro-nanobubbles have garnered significant attention in research due to their commendable stability, biocompatibility, and other notable properties. Currently, the preparation methods of enveloped micro-nanobubbles have limitations such as complicated preparation process, large bubble size, wide distribution range, low yield, etc. There exists an urgent demand to devise a simple and efficient method for the preparation of enveloped micro-nanobubbles, ensuring both high concentration and a uniform particle size distribution. Magnetic lipid bubbles (MLBs) are a multifunctional type of enveloped micro-nanobubble combining magnetic nanoparticles with lipid-coated bubbles. In this study, MLBs are prepared simply and efficiently by a magneto internal heat bubble generation process based on the interfacial self-assembly of iron oxide nanoparticles induced by the thermogenic effect in an alternating magnetic field. The mean hydrodynamic diameter of the MLBs obtained was 384.9 ± 8.5 nm, with a polydispersity index (PDI) of 0.248 ± 0.021, a zeta potential of -30.5 ± 1.0 mV, and a concentration of (7.92 ± 0.46) × 109 bubbles/mL. Electron microscopy results show that the MLBs have a regular spherical stable core-shell structure. The superparamagnetic iron oxide nanoparticles (SPIONs) and phospholipid layers adsorbed around the spherical gas nuclei of the MLBs, leading the particles to demonstrate commendable superparamagnetic and magnetic properties. In addition, the effects of process parameters on the morphology of MLBs, including phospholipid concentration, phospholipid proportiona, current intensity, magnetothermal time, and SPION concentration, were investigated and discussed to achieve controlled preparation of MLBs. In vitro imaging results reveal that the higher the concentration of MLBs loaded with iron oxide nanoparticles, the better the in vitro ultrasound (US) imaging and magnetic resonance imaging (MRI) results. This study proves that the magneto internal heat bubble generation process is a simple and efficient technique for preparing MLBs with high concentration, regular structure, and commendable properties. These findings lay a robust foundation for the mass production and application of enveloped micro-nanobubbles, particularly in biomedical fields and other related domains.

Epithelial cells sacrifice excess area to preserve fluidity in response to external mechanical stress

Viscoelastic properties of epithelial cells subject to shape changes were monitored by indentation-retraction/relaxation experiments. MDCK II cells cultured on extensible polydimethylsiloxane substrates were laterally stretched and, in response, displayed increased cortex contractility and loss of excess surface area. Thereby, the cells preserve their fluidity but inevitably become stiffer. We found similar behavior in demixed cell monolayers of ZO-1/2 double knock down (dKD) cells, cells exposed to different temperatures and after removal of cholesterol from the plasma membrane. Conversely, the mechanical response of single cells adhered onto differently sized patches displays no visible rheological change. Sacrificing excess surface area allows the cells to respond to mechanical challenges without losing their ability to flow. They gain a new degree of freedom that permits resolving the interdependence of fluidity β on stiffness \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${K}_{{{{{{{{\rm{A}}}}}}}}}^{0}$$\end{document}KA0. We also propose a model that permits to tell apart contributions from excess membrane area and excess cell surface area.

The viscoelastic properties of cells subjected to external strain are assessed, showing that cells become stiffer but preserve fluidity by sacrificing their excess surface area.

Advances in receptor modulation strategies for flexible, efficient, and enhanced antitumor efficacy

Tumor-sensitivity, effective transport, and precise delivery to tumor cells of nano drug delivery systems (NDDs) have been great challenges to cancer therapy in recent years. The conventional targeting approach involves actively installing the corresponding ligand on the nanocarriers, which is prone to recognize the antigen blasts overexpressed on the surface of tumor cells. However, there are some probable limitations for the active tumor-targeting systems in vivo as follows: a. the limited ligand amount of modifications; b. possible steric hindrance, which was likely to prevent ligand-receptor interaction during the delivery process. c. the restrained antigen saturation highly expressed on the cell membrane, will definitely decrease the specificity and often lead to "off-target" effects of NDDs; and d. water insolubility of nanocarriers due to excess of ligands modification. Obviously, any regulation of receptors on surface of tumor cells exerted an important influence on the delivery of targeting systems. Herein, receptor upregulation was mostly desired for enhancing targeted therapy from the cellular level. This technique with the amplification of receptors has the potential to enhance tumor sensitivity towards corresponding ligand-modified nanoparticles, and thereby increasing the effective therapeutic concentration as well as improving the efficacy of chemotherapy. The enhancement of positively expressed receptors on tumor cells and receptor-dependent therapeutic agents or NDDs with an assembled "self-promoting" effect contributes to increasing cell sensitivity to NPs, and will provide a basic platform for clinical therapeutic practice. In this review, we highlight the significance of modulating various receptors on different types of cancer cells for drug delivery and therapeutic benefits.