European Biophysics Journal最新文献

Cell permeabilization techniques are widely used to enable intracellular delivery of therapeutic molecules. Although these methods show promise for drug delivery and gene therapy, controlling and quantifying molecular transport at the nanoscale remains a significant challenge due to the structural complexity of mammalian cells. Multivesicular vesicles (MVVs), consisting of a large outer vesicle encapsulating multiple smaller vesicles, offer a simplified biomimetic platform that captures key aspects of cellular compartmentalization of mammalian cells. In this study, we employed finite element method (FEM)-based simulations using COMSOL Multiphysics to investigate passive molecular transport through permeabilized MVVs. The model incorporated biologically relevant pore sizes and three commonly used fluorescent probes of increasing molecular size: Calcein, Texas-red dextran 3000 (TRD-3k), and TRD-10k. The results reveal size-dependent accumulation kinetics. Additionally, transport efficiency was enhanced with increased pore diameter, indicating that both molecular and structural parameters influence delivery outcomes. Importantly, the simulations demonstrate that compartmentalized vesicle structures cause transport to vary across space and time. The model successfully matches experimental results seen in permeabilized vesicles and expands them to more complex nested vesicle systems. These findings highlight the role of vesicle architecture in shaping transport outcomes and provide a computational framework for exploring compartmentalization effects relevant to intracellular delivery strategies.

Embryonic development is intricately regulated by mechanical properties such as stiffness, which influence developmental viability and implantation success – factors critical in assisted reproductive technologies (ART). Traditional embryo evaluation relies predominantly on morphology, lacking quantitative mechanical parameters that could enhance selection accuracy. Recent studies indicate that the stiffness (elasticity) of the zona pellucida (ZP) – the glycoprotein-rich extracellular matrix surrounding mammalian oocytes and embryos – correlates with embryo quality and developmental potential​. However, current biomechanical characterization techniques – including micropipette aspiration, atomic force microscopy (AFM), microtactile sensors, and microelectromechanical systems (MEMS) based sensors – either pose risks of mechanical damage or involve complex, time-consuming procedures unsuitable for clinical settings​. Here, we introduce a novel approach leveraging fluidic force microscopy cantilevers to non-invasively evaluate embryo biomechanics. Our proof-of-concept study demonstrates rapid, precise stiffness profiling of intact mouse embryos (specifically ZP elasticity). Using gentle microsuction attachment with no chemical adhesives or rigid immobilization, the method preserves embryo integrity while providing reproducible elasticity measurements. This method combines the precision of AFM with minimal invasiveness, offering a promising new quantitative biomechanical indicator to augment clinical embryo assessment and paving the way for broader applications in reproductive biology.

Developing small-molecule compounds as effective and safe pharmaceuticals relies on their ability to bind disease-associated proteins with high affinity and selectivity. However, achieving ultra-high affinity in the femtomolar range is a major challenge in medicinal chemistry due to the inherent constraints of protein-ligand interactions. Here, we introduce a novel class of di-meta-substituted fluorinated benzenesulfonamide compounds that achieve an extraordinary dissociation constant of 44 fM for carbonic anhydrase IX (CAIX). CAIX, a transmembrane enzyme implicated in hypoxic tumor progression through the increase of microenvironment acidity, represents a promising target for anticancer therapy. Inhibiting CAIX may help suppress tumor growth and improve cancer treatment outcomes. The newly developed compounds exhibit the highest affinity for CAIX reported to date and rank among the strongest known non-covalent small-molecule inhibitors.

This piece serves two purposes. Firstly, it aims to ascertain the extent to which the ‘principle of least action’ enables us to identify which of the potential pathways and trajectories leading to novel protein sequences have the highest evolutionary efficiency—in addition to examining how variations in factors such as protein robustness and folding rates (resulting from the inevitability of destabilizing mutations) could impact this important evolutionary process. Secondly, it seeks to elucidate how ‘epistasis’ may influence the identification of the most efficient evolutionary pathways and trajectories according to the principle of least action—as well as to determine whether the presence of ‘epistatic effects’ may stem from a yet unidentified epistatic force. The initial findings suggest that protein evolution—at a molecular level—may be more predictable than previously thought, as ‘epistasis’ and the ‘principle of least action’ collectively impose constraints on evolutionary paths and trajectories, and consequently, on protein evolvability. Thus, this work should advance our understanding of the main molecular mechanisms that underlie the evolution of mutation-driven proteins and also provide grounds to answer a fundamental evolutionary question: how does Darwinian selection regard all potential trajectories available?