Search Results (952)

Lactoferrin (Lf) occurs predominantly within milk, coexisting with measurable levels across different glandular products and body fluids. Lf exhibits variation in relative molecular mass, influenced by its biological source and glycosylation profile; nevertheless, it is a close to 80 kDa glycoprotein. Provided that its bioactive structure is preserved, Lf performs a spectrum of physiological roles, comprising antioxidant, antifungal, antiviral, antiapoptotic, and antimicrobial actions. To sustain its bioactivity after isolation and ensure its effectiveness in subsequent applications, optimal conditions must be established throughout the optimization protocol, since inadequate optimization of parameters such as pH, temperature, ion balance, and protease activity may lead to aggregation, denaturation, and deterioration in functional regions, including the iron-binding domains. This review offers a comprehensive framework that associates isolation methodologies with structural integrity, preservation of iron-binding domains, and antimicrobial performance. Ion-exchange, affinity-based, and membrane-based approaches are systematically evaluated from analytical and functional perspectives, thereby yielding a synthesis that facilitates procedure selection and optimization for Lf isolation. In addition, the objectives of analytical characterization techniques implemented following isolation and the broadening scope of biotechnological applications of Lf are outlined. Full article

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by cognitive decline, synaptic dysfunction, and the accumulation of amyloid plaques and neurofibrillary tangles. While prior research has focused mainly on protein aggregation and neuroinflammation, emerging evidence suggests that ionic imbalances, particularly involving sodium (Na⁺) and potassium (K⁺), may contribute to AD progression. Na⁺ and K⁺ are critical for maintaining neuronal membrane potential, regulating action potential firing, and supporting neurotransmitter function. Although studies primarily focused on absolute Na⁺ concentrations, the Na⁺/K⁺ ratio may provide a more sensitive marker of ionic dysregulation. Given that the Na⁺/K⁺ gradient is actively maintained by the Na⁺/K⁺-ATPase pump—a target known to be vulnerable in AD—we hypothesized that the Na⁺/K⁺ ratio is altered in AD. We analyzed postmortem tissue from the prefrontal cortex, thalamus, and cerebrospinal fluid (CSF) of 97 human subjects (67 AD, 30 controls). AD cases exhibited a significant increase in the Na⁺/K⁺ ratio in the thalamus and CSF, driven primarily by elevated Na⁺ levels. The Na⁺/K⁺ ratio positively correlated with Braak tangle stage, suggesting an association with AD progression. These findings provide novel insights into ionic dysregulation in AD and suggest that the Na⁺/K⁺ ratio in the CSF may serve as a valuable biomarker for disease severity and progression. Future research should explore the potential of targeting ionic homeostasis as a therapeutic strategy in AD. Full article

Background/Objectives: Bacterial outer membrane vesicles (OMVs) play a role in bacterial communication, virulence, antimicrobial resistance, and host–pathogen interaction. OMV isolation is a key step for studying these particles’ functions; nevertheless, isolation procedures can greatly influence the yield, purity, and structural integrity of OMVs, thereby affecting downstream biological analyses and functional interpretation. Methods: In this study, we compared the efficacy of two OMV isolation techniques, differential ultracentrifugation (dUC) and size-exclusion chromatography (SEC), in separating and concentrating vesicles produced by two Escherichia coli strains belonging to uropathogenic (UPEC) and Shiga toxin-producing (STEC) pathotypes. The isolated OMVs were characterized using a multi-analytical approach including transmission and scanning electron microscopy (TEM, SEM), nanoparticle tracking analysis (NTA), dynamic light scattering (DLS), ζ-potential measurement, and protein quantification to assess the purity of the preparations. Results: Samples obtained by dUC exhibited higher total protein content, broader particle size distributions, and more pronounced contamination by non-vesicular material. In contrast, SEC yielded morphologically homogeneous and structurally well-preserved vesicles, higher particle-to-protein ratios, and lower total protein content, reflecting reduced co-isolation of protein aggregates. NTA and DLS analyses revealed polydisperse populations in samples obtained with both isolation methods, with DLS measurements highlighting the contribution of larger or transient aggregates. ζ-potential values were close to neutrality for all samples, consistent with limited electrostatic repulsion and with the aggregation tendencies observed in some preparations. Conclusions: This study describes features of OMV produced by two relevant E. coli strains considering two isolation strategies which exert method- and strain-dependent effects on vesicle properties, including size distribution and surface charge, and emphasizes the trade-offs between yield, purity, and vesicle integrity. Full article

The recognition of liquid–liquid phase separation (LLPS) as a widespread organizing principle has revolutionized our view of cellular biochemistry. By forming biomolecular condensates, cells spatially orchestrate reactions without membranes. However, the dysregulation of this precise physical organization is emerging as a driver of diverse pathologies, collectively termed “Condensatopathies.” Unlike traditional proteinopathies defined by static aggregates, these disorders span a dynamic spectrum of material state dysfunctions, from the failure to assemble essential compartments to the formation of aberrant, toxic phases. While research has largely focused on neurodegeneration and cancer, the impact of condensate dysfunction likely extends across broad physiological landscapes. A central unresolved challenge lies in deciphering the “molecular grammar” that governs the transition from functional fluids to pathological solids and, critically, visualizing these transitions in situ. This “material science” perspective presents a profound conundrum for drug discovery: how to target the collective physical state of a protein ensemble rather than a fixed active site. This review navigates the evolving therapeutic horizon, examining the limitations of current pharmacological approaches in addressing the complex “condensatome.” Moving beyond inhibition, we propose that the future of intervention lies in “reverse-engineering” the biophysical codes of phase separation. We discuss how deciphering these principles enables the creation of programmable molecular tools—such as synthetic peptides and state-specific degraders—designed to precisely modulate or dismantle pathological condensates, paving the way for a new era of precision medicine governed by soft matter physics. Full article

Serotonergic signaling is traditionally conceived as a transient, vesicle-mediated process restricted to the synaptic cleft. Here, we propose an expanded model in which serotonin can also be inserted into the plasma membrane of neurons and glial cells, forming a stable, membrane-associated reservoir that prolongs its availability beyond classical synaptic timescales. In this framework, the synapse emerges not as a simple neurotransmitter–receptor interface but as a dynamic, multiscale medium where membrane order, hydration, and quantum-level processes jointly govern information flow. Two temporal “tunnels” appear to regulate serotonin bioavailability: its aggregation in synaptic vesicles during exocytosis, and its cholesterol-dependent insertion into neuronal and glial membranes at the tripartite synapse. Lipid raft microdomains enriched in cholesterol and gangliosides thus act as active regulators of a continuum between transient and constitutive serotonin signaling. This extended serotonergic persistence prompts a reconsideration of current pharmacological models and the action of antidepressants such as fluoxetine, which not only inhibits the serotonin transporter (SERT) but also accumulates in lipid rafts, perturbs raft organization, and alters serotonin–cholesterol equilibria, contributing to SERT-independent effects. Grounded in the recently established fundamental parameters of biological systems, this model invites a broader, quantum-informed rethinking of synaptic transmission. Full article

Neurodegenerative diseases (NDDs), defined by the progressive loss of neurons, present a major challenge to global health. Oxidative stress and lysosomal dysfunction are both key pathogenic factors in NDDs, and they do not operate in isolation; instead, the vicious cycle they form, often mediated through organellar crosstalk, serves as the core driver of the pathological progression of NDDs, collectively worsening disease outcomes. Specifically, excessive reactive oxygen species (ROS) can disrupt lysosomal membrane integrity through lipid peroxidation and inhibit the activity of vacuolar ATPase (V-ATPase), ultimately leading to impaired lysosomal acidification. Meanwhile, lysosomal dysfunction hinders the clearance of damaged mitochondria (the primary endogenous source of ROS), toxic protein aggregates, and free iron ions. This further exacerbates ROS accumulation and accelerates neuronal degeneration. Conventional therapeutic approaches have limited efficacy, primarily due to the challenges in crossing the blood–brain barrier (BBB), insufficient targeting ability, and an inability to effectively intervene in this pathological loop. Nanotherapeutics, leveraging their tunable physicochemical properties and modular functional design, represent a transformative strategy to address these limitations. This review systematically elaborates on the reciprocal interplay between oxidative stress and lysosomal dysfunction in NDDs, with a particular focus on the central role of lysosome-mitochondria axis dysfunction, critically appraises recent advances in nanotechnology-based targeted therapies, and thereby provides a comprehensive theoretical framework to guide the development of novel NDD therapeutics. Full article

Plasmodesmata (PDs) are enriched in sphingolipids and sterols, creating a specialized environment for regulatory proteins like plasmodesmata-localized proteins (PDLPs). How PDLPs regulate PD function in a specific lipid environment remains poorly understood. Here, we provide a unique insight from the interaction network of two different PDLPs together with sphingolipids and propose a concept that PDLPs form homo- or hetero-dimers only in the presence of sphingolipids. Located in the detergent resistance region, PDLP7 demonstrated the ability to influence the sphingolipid composition in PD-enriched fraction, particularly the GIPC content, and finally, modulating the membrane order. The presence of sphingolipids, in turn, affected the oligomeric state of PDLP7 in membranes. The PDLP7 recombinant protein existed as a monomer in vitro, but it formed self-aggregates in yeast and plant cells. We further examined PDLP5, another known phytosphinganine (t18:0)-specific binding PDLP, alongside PDLP7, and confirmed a similar interaction pattern: no direct interaction was observed in vitro, but interactions were noted in vivo. Co-overexpression of the two disrupted their PD localization and induced the upregulation of pathogenesis-related protein 1 (PR1). In summary, we gained insights into the network of PDLPs with lipids and propose that PDLPs were under precise regulation during plant development and stress responses. Full article

Many biomedical applications require a detailed understanding of the action of antimicrobial peptides on biological membranes. The cationic hemolytic peptide melittin, a major component of European honey bee (Apis mellifera) venom, is considered a model for elucidating lipid–protein interactions that are important for the function of biological systems. Here, we address the surface properties of human erythrocytes and rat liver mitochondrial membranes under in vitro melittin treatment. These membranes are negatively charged at neutral pH and represent primary targets of melittin’s effects in the onset of inflammatory diseases. The correlation between the functional activity of membrane systems and their surface electrical charge was assessed using microelectrophoresis, hemolysis assays, membrane transport measurements, lipid peroxidation analysis, and fluorescence microscopy. A mechanistic hypothesis for the divergent effects of sub-lytic, pre-pore doses of melittin on erythrocytes and mitochondria is discussed. At low concentrations, melittin interacts electrostatically with erythrocyte membranes, resulting in altered proton transport through the Band 3 protein. Melittin also induces changes in erythrocyte morphology and malondialdehyde content, as well as aggregation of mitochondrial vesicles. The electrokinetic mechanism of melittin action, associated with membrane stability, provides a novel perspective on its potential relevance to biomedical applications. Full article

The hydrophobic region of semaglutide makes it prone to aggregation in aqueous solution, which leads to serious interception in microfiltration. The influences of pH and low concentrations of salts (NaCl, CH₃COONa, Na₂SO₄ and (NH₄)₂SO₄) on the particle size and zeta potential of semaglutide aggregates were studied in this work. The results showed pH could change the zeta potential on the semaglutide surface, but the impact on semaglutide dispersion was limited. When salts were introduced into aqueous solution, NaCl had a more significant dispersion effect on semaglutide than other salts. Under pH 2.5 or pH 8.0 conditions, the addition of 0.01 mol/L NaCl reduced the average particle size of semaglutide aggregates to below 70 nm. The permeability of semaglutide in microfiltration increased from 60% to 86% under optimized conditions with the PES membrane (0.22 μm), and the adsorption loss also reduced 40%. In addition, this study compared the HPLC detection precision of semaglutide samples prefiltered with different microfiltration filters. Some semaglutide was intercepted by various microfiltration filters, resulting in serious detection errors. When semaglutide was dissolved in the aqueous solution containing 0.01 mol/L NaCl with pH 2.5, the detection error was controlled within 1%. Full article

Virus filtration is an essential unit operation used to validate clearance of adventitious virus during the manufacture of biopharmaceutical products such as monoclonal antibodies. Obtaining at least a 10,000-fold reduction in virus particles in the permeate is challenging as monoclonal antibodies are about half the size of the virus particles. Minute virus of mice, FDA-recommended model adventitious virus, was labeled with a fluorescent dye. Laser scanning confocal microscopy was used to determine the location of virus entrapment within the virus filtration membrane. Three different hollow fiber membranes made of regenerated cellulose and polyvinylidene fluoride were tested. Feed streams consisted of MVM spiked in buffer and MVM spiked in 5 g L⁻¹ bovine serum albumin known to contain aggregates similar in size to the MVM. After filtering the feed, a buffer flush was used, with and without 30 min pause before the buffer flush. For all virus filters, a 30 min process pause led to broadening and movement of the virus entrapment zone deeper into the membrane. The presence of aggregates led to greater broadening of the entrapment zone. Both effects could lead to reduced virus clearance. Visualization of virus entrapment helps improve understanding of the behavior of virus filtration membranes. Full article

Magnetosomes (MTS), membrane-enclosed magnetic nanoparticles naturally biomineralized by magnetotactic bacteria, are promising materials for tumor hyperthermia owing to their good biocompatibility and heating efficiency. However, their application is limited by poor suspension stability and low injectability at high concentrations. This study aimed to enhance magnetosome stability and delivery performance through surface cationization combined with collagen matrix stabilization. The resulting cationic magnetosomes (CMTS) exhibited an increased positive charge on the outer membrane. Collagen, functioning as a negatively charged matrix under mildly alkaline conditions, effectively stabilized the cationic magnetosomes, forming CMTS–collagen aqueous suspensions (CMTS-Colas) that remained well-suspended for over 24 h and could be easily resuspended after 10 days of storage. Compared with native magnetosome suspensions, CMTS in collagen displayed smaller hydrodynamic diameters and significantly improved injectability through 26G and 31G fine needles. Under an alternating magnetic field, 2 mg/mL CMTS-Colas efficiently induced over 98% apoptosis in hepatoma cells after two treatment sessions and led to complete loss of cell viability after three sessions. These findings demonstrate that CMTS-Colas substantially improve the suspension stability and injectability of magnetosomes while maintaining strong hyperthermic efficacy, suggesting a promising strategy for stabilizing magnetosomes and potentially benefiting other charged, aggregation-prone magnetic biomaterials. Full article

Lysosomes are central effectors of cellular maintenance, integrating the degradation of damaged organelles and protein aggregates with macromolecule recycling and metabolic signaling. In neurons, lysosomes are particularly crucial due to the cells’ long lifespan, polarized architecture, and high metabolic demands. Proper regulation of lysosomal function is essential to sustain proteostasis, membrane turnover, and synaptic integrity. Although lysosomal dysfunction has been extensively studied in neurodegenerative diseases, far less is known about how lysosomal capacity and function are maintained—or fail to be maintained—with age in non-diseased neurons. In this review, we summarize current understanding of neuronal lysosomal dynamics, discuss methodological challenges in assessing lysosomal capacity and function, and highlight recent advances that reveal age-associated decline in neuronal lysosomal competence. Full article

Rare-earth oxide (REO) nanoparticles (NPs)—such as cerium (CeO₂), samarium (Sm₂O₃), neodymium (Nd₂O₃), terbium (Tb₄O₇), and praseodymium (Pr₂O₃)—have demonstrated strong antimicrobial activity against multidrug-resistant bacteria. Their effectiveness is attributed to unique physicochemical properties, including oxygen vacancies and redox cycling, which facilitate the generation of reactive oxygen species (ROS) that damage microbial membranes and biomolecules. Additionally, electrostatic interactions with microbial surfaces and sustained ion release contribute to membrane disruption and long-term antimicrobial effects. REOs also inhibit bacterial enzymes, DNA, and protein synthesis, providing broad-spectrum activity against Gram-positive, Gram-negative, and fungal pathogens. However, dose-dependent cytotoxicity to mammalian cells—primarily due to excessive ROS generation—and nanoparticle aggregation in biological media remain challenges. Surface functionalization with polymers, peptides, or metal dopants (e.g., Ag, Zn, and Cu) can mitigate cytotoxicity and enhance selectivity. Scalable and sustainable synthesis remains a challenge due to high synthesis costs and scalability issues in industrial production. Green and biogenic routes using plant or microbial extracts can produce REOs at lower cost and with improved safety. Advanced continuous flow and microwave-assisted synthesis offer improved particle uniformity and production yields. Biomedical applications include antimicrobial coatings, wound dressings, and hybrid nanozyme systems for oxidative disinfection. However, comprehensive and intensive toxicological evaluations, along with regulatory frameworks, are required before clinical deployment. Full article

The design of the chemical structure of ion-conductive membranes is critical to enhance proton/vanadium ion selectivity and the performance of vanadium redox flow batteries (VRFBs). Herein, camphorsulfonic acid is proposed as a novel proton-conductive group and grafted on polybenzimidazole (PBICa). The pendant sulfonic acid group on the end of the grafted side chains is flexible to promote the aggregation of ionic clusters at even a relatively low ion-exchange capacity (IEC) of 2.14 mmol g⁻¹. The formation of these high-quality clusters underscores the remarkable efficacy of this structural strategy in driving nanoscale phase separation, which is a prerequisite for creating efficient proton-conducting pathways. The bulky and non-coplanar architecture of the camphorsulfonic acid group helps to increase the proportion of free volume compared with the conventional sulfonated polybenzimidazole, which not only promotes water uptake to facilitate proton transport but also exerts a sieving effect to effectively block vanadium ion permeation. The well-formed ionic clusters, together with the expanded free volume architecture, endow the membrane with both high proton conductivity (30.5 mS cm⁻¹) and low vanadium ion permeability (0.15 × 10⁻⁷ cm² s⁻¹), achieving excellent proton/vanadium ion selectivity of 9.85 × 10⁹ mS s cm⁻³, which is about 5.6-fold that of a Nafion 212 membrane. Operating at 200 mA cm⁻², the PBICa-based VRFB achieves an energy efficiency of 78.4% and a discharge capacity decay rate of 0.32% per cycle, outperforming the Nafion 212-based battery (EE of 76.9%, capacity decay of 0.79% per cycle). Full article

The cell-penetrating peptide Pep-1 interacts with lipid membranes through combined electrostatic and hydrophobic forces, yet the structural details of its membrane remodeling activity remain unclear. Using atomic force microscopy (AFM), we examined how Pep-1 perturbs supported lipid bilayers of varying composition and geometry. In zwitterionic POPC bilayer patches, Pep-1 preferentially targeted patch boundaries, where lipid packing is less constrained, leading to edge erosion and detergent-like disintegration. Incorporation of anionic POPS enhanced peptide binding and localized disruption, giving rise to elevated annular rims, holes, and peptide–lipid aggregates. In cholesterol-containing POPC bilayer patches, Pep-1 induced extensive surface reorganization marked by protruded, ridge-like features, consistent with lipid redistribution and curvature generation. In continuous POPC/POPS bilayers lacking free edges, Pep-1 formed discrete, flower-like protrusions that coalesced into an interconnected network of thickened peptide-rich domains. These findings reveal composition-dependent remodeling pathways in which Pep-1 destabilizes, reorganizes, or curves membranes according to their mechanical and electrostatic properties, providing new insight into peptide–membrane interactions relevant to cell-penetrating peptide translocation. Full article