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Colloids and Surfaces B: Biointerfaces

Elsevier BV

Preprints posted in the last 90 days, ranked by how well they match Colloids and Surfaces B: Biointerfaces's content profile, based on 10 papers previously published here. The average preprint has a 0.01% match score for this journal, so anything above that is already an above-average fit.

1
A Bottom-Up Approach to Fungal Plasma Membrane Model: Lipid Mixture Design and Biophysical-Mechanical Characterization

Kucharski, M.; Kubicka, Z.; Drabik, D.

2026-08-17 biophysics 10.64898/2026.08.08.743690 medRxiv
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The rising incidence of invasive fungal diseases emphasizes the need for novel therapeutic strategies, including membrane-targeting antifungal agents, which require representative lipid models for detailed molecular-level studies. In this work, we propose a consensus quinary fungal plasma membrane model based on lipidomic literature data, specifically PC:PE:PI:PA:PS phospholipid model with ratio of 44:29:13:8:6. Using a bottom-up approach, we characterized the biophysical properties of this system - with particular emphasis on mechanical parameters such as bending rigidity and area compressibility - by combining molecular dynamics simulations with experimental flicker-noise and ATR-FTIR spectroscopies. Furthermore, we investigated the effect of two key non-phospholipid components: ergosterol and triacylglycerols. Biophysical analysis revealed that DPPI and its specific interactions with DSPS induced the most substantial deviations in baseline membrane parameters, particularly area per lipid, membrane thickness, and area compressibility, while DSPS influenced bending rigidity change and DLiPA primarily affected lipid packing defects. In addition, ergosterol and TGs were found to influence all of the investigated parameters to different degree. Notably, the overall biophysical profile of the proposed FPMM closely mimicked that of natural vesicles derived from yeast lipid extracts, establishing this model may provide a reliable platform for studying fungal membrane biophysics and lipid-targeting interactions.

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Stability and Compressibility of Tear Film Lipid Layer: Impact of Benzalkonium Chloride Presence

Chen, J.; Zhang, Y.; Nguyen, T. M. H.; Tsukruk, V. V.

2026-06-17 biophysics 10.64898/2026.06.13.731656 medRxiv
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PURPOSEBenzalkonium chloride (BAK), a common preservative in eye drops, has a major side effect of dry eye. The mechanisms are typically attributed to BAK cytotoxicity. However, due to its surfactant properties, BAK can disrupt the tear film lipid layer (TFLL), leading to dry eye. This study examined the stability and compressibility of the TFLL and the impact of the presence of BAK. METHODSMeibomian gland secretion (meibum, source of the TFLL) was collected from sacrificed cows eyelids. Lipids were extracted by dissolving meibum in chloroform to a final concentration of 1 mg/mL, with one solution additionally containing 0.1 mg/mL BAK. Each solution was overlaid on a water subphase in a Langmuir Trough-Blodgett trough. The changes of surface pressure ({pi}) with area (A) for the lipid film upon compression were monitored, and the corresponding compression modulus (Cs-1) at each data point was determined. RESULTSThe {pi}-A isotherms for meibum lipid monolayers exhibited near-reversible behavior with a smooth profile with a maximum {pi} of approximately 32 mN/m. The Cs-1-{pi} isotherms of the meibum lipid monolayer show that the films are gel-like with a constant compressive modulus of 24-32 mN/m within the surface pressure range of 8-30 mN/m. In contrast, adding BAK dramatically decreased the maximum surface pressure to only 10 mN/m and the compressive modulus to only 2-10 mN/m. CONCLUSIONSThis study demonstrated that BAK disrupts the meibum lipid layer by forming a monolayer with decreased stability and reduced compressive resistance, a mechanism that may underlie its dry-eye side effect yet has largely been neglected.

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The comparative strengths and limitations of Nile Red and 9-(dicyanovinyl)-julolidine (DCVJ) fluorescent dyes for detecting microplastics and nanoplastics

Wallner, M.; Diaz, J.; Labbe, A. B.; Jacob, J. J.; Williams, Q.; Paytan, A.; Bagshaw, C. R.

2026-08-07 biophysics 10.64898/2026.08.03.742549 medRxiv
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Nile Red is widely used for the detection of microplastics because its fluorescence emission is sensitive to local polarity and can distinguish hydrophobic plastics from hydrophilic ones. The fluorescence of the molecular rotor, 9-(dicyanovinyl)-julolidine (DCVJ) is less sensitive to polarity but more to viscosity. DCVJ is less widely used for microplastic analysis, although it has been used to detect polystyrene nanobeads. Here, we compared these dyes with standard samples from the Hawaii Pacific University Polymer Kit 1.0 and confirmed that Nile Red, in general, was better for the detection and identification of microplastics. Fluorescence emission was analyzed using photography, as well as spectroscopy. The color and peak emission wavelength of some stained environmental microplastics were affected by additives. Raman spectroscopy was used to confirm the chemical identity of such samples. Although DCVJ emits green fluorescence on binding to some microplastics, a peak at 620 nm has been reported with polystyrene nanobeads, attributed to dimer/excimer formation. We confirmed this property and directly observed diffraction-limited spots using fluorescence microscopy, attributed to single or just a few nanobeads. Nile Red also stains polystyrene nanobeads and gave stronger signals than with DCVJ, but Nile Red was prone to false positives due to dye aggregation in aqueous solutions.

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An Effective Metal Nanoparticle-Based Drug Delivery System for an In Vitro Model of Non Small Cell Lung Cancer

Piergies, N.; Ocwieja, M.; Pogoda, K.; Panek, A.; Roman, M.; Raszka, K.; Kwiatek, W. M.

2026-06-09 biophysics 10.64898/2026.06.05.730380 medRxiv
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This study presents the development and spectroscopic characterization of an erlotinib-functionalized gold nanoparticle (erlotinib:AuNP) nanosystem designed for targeted delivery to metastatic non-small cell lung cancer H1299 cells. Initial MTS assays demonstrated that free erlotinib induced a concentration-dependent reduction in cell viability, while 0.1 {micro}M erlotinib exhibited negligible cytotoxicity and was therefore selected for nanosystem fabrication. AuNPs alone showed minimal toxicity toward H1299 cells over the investigated concentration range. Following conjugation of erlotinib with AuNPs, the resulting nanosystems reduced cell viability to approximately 60%, indicating enhanced biological activity of the drug after nanoparticle-assisted delivery. Fluorescence microscopy confirmed the intracellular internalization of the nanosystems in H1299 cells, with nanoparticle aggregates predominantly localized in the perinuclear and perimitochondrial regions. Three-dimensional Raman spectroscopy (3D RS) mapping further verified the intracellular localization of the conjugates through characteristic Raman signatures of erlotinib:AuNPs. Importantly, 3D RS enabled detection of nanosystems at concentrations below the sensitivity limit of fluorescence imaging, demonstrating superior analytical performance for intracellular nanosystem tracking. Atomic force microscopy-infrared (AFM-IR) spectroscopy coupled with principal component analysis (PCA) demonstrated substantial biochemical modifications induced by the erlotinib:AuNP nanosystems, including enhanced lipid-related spectral features and significant alterations in protein secondary structure, particularly the increased contribution of unordered and antiparallel {beta}-turn conformations. The obtained results demonstrate that combining plasmonic nanocarriers with advanced vibrational spectroscopy enables highly sensitive monitoring of intracellular drug delivery and nanosystem-induced biochemical responses in cancer cells.

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Surface Functionality and pH Govern Structural Dynamics and Drug Binding in PETIM and PAMAM Dendrimers

Garg, A.; Mogurampelly, S.; Kanchi, S.

2026-08-07 biophysics 10.64898/2026.08.04.742721 medRxiv
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1.Surface functionality and pH play a decisive role in governing the structural dynamics, hydration, and drug-binding behaviour of dendrimers. Here, all-atom molecular dynamics (MD) simulations were performed on five generations of PAMAM (G1-G5) and PETIM (G2-G6) dendrimers with O-core and N-core architectures, functionalized with amine, carboxylic acid, or sugar terminal groups under different protonation states. Protonation of the tertiary branch-point amines expands the dendrimer structure, increases internal porosity and hydration, and enhances structural fluctuations across both families. In contrast, non-protonated amine -NH2 (NP) and carboxylic acid -COOH (NP) terminated dendrimers, together with deprotonated carboxylate-COO- (DeP) systems, retain comparatively compact conformations. Sugar-functionalized dendrimers ({beta}-galactose-terminated PETIM and D-glucose-terminated PAMAM) are most hydrated and structurally rigid, whereas amine-terminated dendrimers exhibit the greatest conformational dynamics. PAMAM dendrimers with -NH2, -NH3+, and -COO- terminal groups are generally more hydrated than their PETIM counterparts. However, {beta}-galactose-terminated PETIM dendrimers are more hydrophilic than D-glucose-terminated PAMAM dendrimers. N-core PETIM dendrimers also adopt more compact and spherical conformations than equivalent O-core PETIM dendrimers. Drug-binding MD simulations show that curcumin binding is dominated by van der Waals (vdW) interactions, whereas doxorubicin complexation is primarily driven by electrostatic interactions. Among the investigated surface functionalities, -NH2 (NP), -NH3+ (P), -COOH (NP), and -COO- (DeP) terminations exhibit the most favourable drug-binding characteristics. Except for deprotonated carboxylate systems, curcumin binds more strongly than doxorubicin. Overall, these findings establish molecular-level relationships between surface functionality, protonation state, dendrimer architecture, and drug-binding behaviour, providing design principles for pH-responsive dendrimer nanocarriers with enhanced drug-loading and controlled-release performance. TOC O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=75 SRC="FIGDIR/small/742721v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@119bf29org.highwire.dtl.DTLVardef@1554d86org.highwire.dtl.DTLVardef@154a254org.highwire.dtl.DTLVardef@16d5c5b_HPS_FORMAT_FIGEXP M_FIG C_FIG

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Green Synthesized Zinc Oxide Nanoparticles from Azadirachta indica Exhibit Enhanced Antibacterial, Antioxidant and Cytotoxic Activities

Manzoor, S.; Arif, T.; Rafiq, H.; Younas, S.; Akter, S.

2026-08-12 microbiology 10.64898/2026.08.12.744370 medRxiv
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Green synthesis of zinc oxide nanoparticles (ZnO NPs) offers a sustainable strategy for developing multifunctional antimicrobial nanomaterials. In this study, ZnO NPs were synthesized using Azadirachta indica leaf extract and characterized by UV-vis spectroscopy, FTIR, XRD, SEM, and GC-MS. The nanoparticles exhibited a characteristic absorption peak at 352 nm, a direct band gap of 3.07 eV, and hexagonal wurtzite crystallinity with an average crystallite size of approximately 32 nm. The biosynthesized ZnO NPs showed concentration-dependent antibacterial activity against Erwinia carotovora, producing inhibition zones of up to 25.9 mm. Mechanistic studies revealed significant membrane damage, evidenced by 4.77-fold and 5.62-fold increases in extracellular protein and amino acid leakage, respectively, with marked alterations in bacterial protein profiles detected by SDS-PAGE. The nanoparticles also exhibited strong antioxidant activity, achieving 89.4% DPPH radical scavenging, and induced dose-dependent cytotoxicity in HepG2 cells with an estimated IC50 of 124.8 g/mL. These findings demonstrate that neem-mediated ZnO nanoparticles possess potent antibacterial activity through membrane disruption while exhibiting promising antioxidant properties, highlighting their potential as eco-friendly nanomaterials for the management of bacterial soft rot and other phytopathogenic diseases.

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Microencapsulation of Nisin in Polyelectric complexes of alginate-chitosan for extended antimicrobial activity

Anumudu, C. K.; Miri, T.; Onyeaka, H.

2026-08-17 microbiology 10.64898/2026.08.14.744846 medRxiv
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Nisin is a promising antimicrobial peptide widely used in food preservation due to its efficacy against Gram-positive spoilage and pathogenic bacteria. Although Nisin is increasingly applied in the food sector, the biopeptide suffers from instability within food matrixes and can rapidly lose its antimicrobial potential following interaction with food biomolecules. Thus, it is necessary to investigate approaches that can be employed to extend the stability and activity of Nisin. Hence, the aim of this study was to develop and characterise a chitosan-alginate polyelectrolyte microencapsulation system capable of enhancing Nisin stability while retaining antimicrobial activity. The microencapsulation of Nisin was achieved by pre-gelation of alginate using calcium chloride and subsequent direct electrostatic interaction between cationic Nisin and chitosan with pre-gelled anionic alginate at pH 5.0. Following microcapsule formation, physicochemical and structural characterisation was performed using Zeta potential determination and measurement of the polydispersity index (PDI) via dynamic light scattering. SEM micrographs were used to confirm morphology, while Fourier-transform infrared (FTIR) spectroscopy and high-performance liquid chromatography (HPLC) were utilised to assess chemical integrity and functional group preservation of encapsulated Nisin. Following this, stable microcapsules with diameters ranging from 150-200 nm and smooth surface morphology were obtained. Microcapsule formation was strongly influenced by formulation parameters, particularly pH, calcium ion concentration, and chitosan content, with deviations from optimal acidic conditions (< pH 5.0) resulting in aggregation, increased polydispersity, and reduced encapsulation efficiency. The microcapsules were monodispersed (PDI {approx} 0.30) and electrostatically stable, exhibiting a Zeta potential of approximately +36 mV. These microcapsules remained stable over a prolonged storage period of 21 days under refrigerated conditions while retaining antimicrobial activity against Bacillus cereus. Encapsulation efficiency reached approximately 65%, confirming effective retention of Nisin within the polymer matrix. Overall, the findings demonstrate that chitosan-alginate ionic gelation is a non-denaturing and effective encapsulation strategy for extending the functional stability of Nisin. These microcapsules show strong potential as natural antimicrobial delivery systems for food and beverage applications, particularly in acidic food matrices, with implications for improved food safety and shelf-life extension.

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Fusion peptides of enveloped viruses actively mediate membrane fusion in model cell membranes

Mohammadian, M.; Seemann, R.

2026-06-07 biophysics 10.64898/2026.06.05.729768 medRxiv
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Enveloped viruses can enter host cells by fusing their membrane with that of the host cell, a process known as membrane fusion. This process depends on specific fusion proteins located on the viral particle surface, which contain a short, relatively hydrophobic segment called "fusion peptide" that binds to the host membrane. To investigate the fusion efficiency of various fusion peptides, we create simplified non-infectious virus like particles decorated with different fusion peptides and fuse them with an artificial cell membrane. For this purpose, microfluidic devices are used to create supported lipid bilayers while the result of the fusion process is studied by fluorescence microscopy. Our study provides structural insights into the interactions between virus particles and cell membranes, which can facilitate the development of new therapeutic strategies and more effective viral vectors for therapeutic applications.

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Excited state Relaxation Activation Energy (ESRAct) of Di-4-ANEPPDHQ Maps Nanoscale Molecular Organization in Biomembranes

Medda, D.; Tripathy, A.; Bag, N.

2026-07-17 biophysics 10.64898/2026.07.17.739057 medRxiv
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Live cell plasma membranes show spatially heterogeneous liquid-ordered (Lo)-like and liquid-disordered (Ld)-like regions similar to the co-existing Lo/Ld phases observed in lipid vesicles. The Lo-like regions are relatively less hydrated and less polar due to tight packing of the membrane components compared to the Ld-like regions. The steady-state fluorescence spectra of Di-4-ANEPPDHQ (Di-4), a widely used polarity-sensitive probe, is blue or red shifted when solvated in less polar (Ld- like) or more polar (Lo-like) regions respectively. However, quantification of Di-4 fluorescence in blue and red channels for the evaluation of membrane phase state suffers from the lack of specific wavelength choice for these two channels and Di-4s relatively higher concentration in Ld phase (red channel) due to its partitioning preference. To address these issues, we employed fluorescence lifetime of Di-4, a concentration independent photophysical parameter, to understand membrane biophysical properties. The fluorescence lifetime of Di-4 in lipid vesicles exhibits Arrhenius-like temperature dependence. Centred around this energetic feature of Di-4 photophysics, we developed a novel analytical module, namely excited state relaxation activation energy (ESRAct), that serves as an intrinsic descriptor of the membrane nano-environment sensed by this probe. We show that the ESRAact value scales with increasing disorder in nanoscale phase separation (i.e., ESRAct of pure Ld > mixed Ld/Lo > pure Lo phase). We then extended its applications to giant plasma membrane vesicles (GPMVs) isolated from MCF-7 cells and found that these vesicles exhibit nanoscale Lo/Ld co-existing phase within 16-37{degrees}C. We envisage wide applications of ESRAct to delineate plasma membrane phase behavior as well as general photophysical studies on other newly designed polarity-sensitive probes.

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Biophysical characterization of novel biomarkers and bioaffinity reagents (NanoMIPs): on the road for a low-cost diagnostic test for intestinal schistosomiasis

Isopo, F.; Stephen, A. N.; Boumis, G.; Giorgi, A.; Eberini, I.; Reddy, S. M.; Miele, A. E.

2026-07-31 biophysics 10.64898/2026.07.28.741194 medRxiv
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Schistosoma mansoni is a vector-borne intestinal parasite, endemic in [~]70 tropical countries. Most of the World Health Organization interventions are based on mass drug administration (MDA) and sanitation. Since the parasite does not induce permanent immunity, reinfection rate is high, inducing scheduling of several MDA campaigns. To follow up after treatment and avoid blind MDA, providing a new rapid and cheap diagnostic test is needed, since the most used method is fifty years-old, lacks sensitivity and efficiency. Venom Allergen-Like proteins (SmVALs) have been previously identified as secreted/excreted proteins and potential biomarkers. Here we present the biophysical characterization of SmVAL11 and SmVAL13, their recognition by both specific antibodies and molecularly imprinted polymers (nanoMIPs), an easy-to-standardize alternative. The specific antibodies showed no cross-reactivity, while initial characterization of the nanoMIPs indicates a promising level of selectivity, establishing them as a reliable, cost-effective alternative. Therefore, our results are promising for the future development of a new cheap diagnostic test of intestinal schistosomiasis.

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Atomistic Simulation of Blood Brain Barrier Permeability of Propolis Derived Natural Compounds

Kumar, V.; Kaul, S. C.; Wadhwa, R.; Sundar, D.

2026-06-10 biophysics 10.64898/2026.06.08.730943 medRxiv
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The ability of small molecules to cross the blood-brain barrier (BBB) remains a major bottleneck in neurotherapeutic development. While experimental assays and machine learning approaches provide approximate permeability estimates, they lack atomistic insight into the underlying transport mechanisms. Here, we employ all-atom molecular dynamics simulations of a compositionally realistic BBB lipid bilayer to characterize the passive permeation of two bioactive propolis-derived compounds, Caffeic Acid Phenethyl Ester (CAPE) and Artepillin-C (ARC). Using steered molecular dynamics and umbrella sampling, we computed free energy profiles, diffusion coefficients, and permeability metrics across the membrane. CAPE encounters a modest barrier at the lipid headgroup region but minimal resistance within the hydrophobic core, resulting in a low free energy barrier ([~]2-3 kcal/mol) and favorable permeability (logP_eff {approx} 0.28). In contrast, ARC exhibits a substantial energetic barrier within the membrane core, leading to high resistivity and strongly unfavorable permeability (logP_eff {approx} -10.91). The heterogeneous lipid model reproduces experimentally consistent membrane properties and reveals how lipid composition modulates transport energetics. These findings provide mechanistic insight into BBB permeability and demonstrate the utility of atomistic simulations for guiding the design of neuroactive therapeutics.

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Elemental Analysis of Herbal Food Supplements using ICP-MS for Toxicant and Nutritional Profiling

Asres, Y. H.; Mathuth, M.

2026-06-23 biophysics 10.64898/2026.06.17.733016 medRxiv
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Botanical dietary supplements (like wheat, barley, teff, oats, white lupin, pumpkin seed, and chickpeas) may contain trace amounts of toxicants in addition to important micronutrients. Developing and validating a reliable protocol for the simultaneous quantification of Cu, Fe, Zn, Mo, Se, Mn, Pb, Al, Ni, and Cr using a PerkinElmer (NexIONTM2000 model) quadrupole ICP MS (including a He collision and reaction cell when needed) with closed vessel microwave digestion using (HNO3 + H2O2) was the aim of this study.The method was subsequently utilized in a sample survey, and the outcomes were evaluated against WHO/JECFA standards. From five study regions, twenty-seven farm-collected botanical powder samples representing seven species were acquired. To create one composite per species, field subsamples were cleaned, air dried, ground, and blended (nine subsamples per botanical: three grabs from each of three farms). HNO3/H2O2 was used to digest aliquots (0.250-0.500gm) in closed microwave containers. Internal standards, multi-point external calibration, procedural blanks, verified reference materials, matrix spikes, and duplicates were all used in ICP MSs multi-element quantitation. Method LODs/LOQs, accuracy (CRM recoveries), and precision (RSD) were calculated.The technique produced low LODs that were suitable for dietary evaluation (typical LOD ranges: Cu, Fe, Zn, Mn, Ni, Cr (0.001-0.01) mg/kg; Mo, Se, Pb, Al (0.002-0.05) mg/kg. For the majority of analytes, within-run RSDs were less than 5%, while CRM recoveries ranged from 88.9 to 110%. The concentrations of essential elements varied greatly (average mg/kg: Fe (280.7{+/-}25.6); Zn (6.0{+/-}0.541); Cu (2.8{+/-}0.269); Mn (398.3{+/-}23.8); {micro}gm/kg: Se (0.061{+/-}0.006); Mo (1.0 {+/-}0.022). Although some composites approached or exceeded conservative intake thresholds for Pb and Al under high consumption scenarios, toxic elements were generally low (mean mg/kg: Pb (0.062{+/-}0.007); Al(185.2{+/-}18.5); Ni(1.6{+/-}0.163); Cr(1.8{+/-}0.171).For the simultaneous nutritional and contaminant profiling of supplements derived from cereals and those not, the validated ICP- MS workflow with microwave HNO3 and H2O2 digestion is suitable. Accurate labeling and consumer safety can be supported by routine screening and supply chain controls.

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Lipid anchor engineering controls cell-penetrating arginine-rich peptide presentation for efficient siEGFR liposomal delivery to triple-negative breast cancer cells

Bialecki, P.; Braccia, S.; Makowski, T.; Piorecka, K.; Falcigno, L.; Bellavita, R.; Falanga, A.; Bryszewska, M.; Robaszkiewicz, A.; Galdiero, S.; Pedziwiatr-Werbicka, E.

2026-08-25 biophysics 10.64898/2026.08.20.745705 medRxiv
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Understanding the physicochemical factors that govern siRNA nanocarrier assembly is essential for the rational design of effective delivery systems. By optimizing various lipid compositions, cholesterol content and PEG length we created a peptide-functionalized cationic liposomal platform made of DOPE/TAP lipids with cholesterol-anchored nona-arginine (R9-Chol) for siRNA complexation, intracellular transport and effective silencing of the target EGFR gene. Analysis of {zeta}-potential and dynamic light scattering allowed to rationally design formulation of stable, monodisperse nanoscale lipoplexes with a positive surface charge. With fluorescence polarization, circular dichroism and agarose gel electrophoresis we found an optimal siRNA:liposome complexation ratio of 1:77, which protected siRNA from ribonuclease-mediated degradation. Morphological imaging confirmed a shift from discrete vesicular structures to organized multilamellar lipoplexes, consistent with electrostatically driven self-assembly. In cellular studies, the optimized nanocarrier promoted efficient uptake of fluorescent siRNA in MDA-MB-231 cells and achieved functional delivery of anti-EGFR, leading to substantially reduced expression of the target gene at both transcript and protein levels. This work offers mechanistic understanding of peptide-assisted lipid:siRNA assembly and positions R9-functionalized DOPE/TAP liposomes as a promising platform for siRNA delivery.

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Surface-specific film assembly of a Vibrio cholerae adhesin peptide modulated by environmental salts

Zhai, S.; Jaramillo Pinto, D. R.; Mendoza, N. L.; Adewole, A.; Heufner, B.; Merg, A. D.; Corrales, T. P.; Yan, J.; Andresen Eguiluz, R. C.

2026-06-23 biophysics 10.64898/2026.06.21.733527 medRxiv
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Underwater adhesion research increasingly draws on bioinspired systems to uncover the molecular mechanisms that enable strong interfacial binding in aqueous environments. The biofilm adhesin Bap1 from Vibrio cholerae contains a short peptide motif, SYWFFGWHTK (CP), which exhibits exceptional adhesive performance, surpassing mussel foot protein mfp5 under comparable conditions. Despite its promise, the roles of ionic environments and aggregation behavior in governing CP adhesion remain unclear. In this study, we investigate how ion identity influences CP aggregation, film formation, and interfacial properties. Using dynamic light scattering, we identify the formation of micron-scale assemblies of aggregated molecular clusters (AAMCs), with size distributions modulated by salt type. Quartz crystal microbalance with dissipation and liquid atomic force microscopy reveal that CP film formation is both surface- and ion-dependent. On gold substrates, AAMCs preferentially adsorb and collapse into rigid, smooth nanofilms, consistent with hydrophobic-driven compaction. In contrast, silicate surfaces inhibit such collapse, yielding distinct morphologies and interfacial energetics. These findings demonstrate that surface chemistry and ionic conditions jointly regulate peptide aggregation and adhesion. This work provides mechanistic insight into hydrophobic-rich peptide systems and informs the rational design of next-generation wet adhesives, with broader implications for biomaterials and peptide-based formulations. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=130 SRC="FIGDIR/small/733527v1_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@1bd012aorg.highwire.dtl.DTLVardef@1977892org.highwire.dtl.DTLVardef@16cf79borg.highwire.dtl.DTLVardef@f405bf_HPS_FORMAT_FIGEXP M_FIG C_FIG

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Effect of microampere-scale wireless conductive microelectrostimulation on Aspergillus fumigatus growth on solid cultures

Kambouris, M. E.; Kritikou, S.; Milioni, A.; Ludovici, G. M.; Karageorgou, K.; Velegraki, A.

2026-08-11 microbiology 10.64898/2026.08.10.743807 medRxiv
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The effect of microcurrents on facultative microbial pathogens remains controversial. Solid cultures in Sabouraud Glucose Agar of the ubiquitous mold Aspergillus fumigatus were repeatedly treated with a commercially available device performing wireless conductive microelectrostimulation by 3.5 A microcurrent routed by spraying negatively charged air particles onto solid cultures in modified petri dishes. The treated cultures displayed increased growth compared to standard ones, but only as a function of mycelial density and total surface; the radial growth rate of the mycelium remained unaltered. The increased growth was positively related to the duration of the treatment. At the same time, secondary development (new mycelial loci within the dish) was greatly upheld due to treatment, as the spraying created microairstreams dislocating the fungal spores. These results imply perplexed kinetics of mycelial growth both with and without treatment, since the folding of the mycelial mat is observed regularly. Both the fungus response to the ES and the possible revision of growth kinetics create prospects for biotechnological and bioremediation applications but also imply biomedical considerations, regarding infection dynamics of mycelial fungi and their in situ resistance to immune responses and treatment.

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New solid-state optical pH sensors for cell analysis

Li, L.

2026-08-09 biophysics 10.64898/2026.08.04.742867 medRxiv
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Monitoring pH and extracellular acidification rate (ECA) in biological samples containing live mammalian cells can provide valuable information on the glycolytic activity and bioenergetic status of cells. Compared to pH electrodes, optochemical pH sensors look more advantageous, since they allow rapid, non-invasive parallel analysis of multiple samples with stable readout of pH. We have developed new fluorescent pH sensors based on hydrophobic protonable metal-free porphyrins,OEP and OEPK, embedded in a plasticized PVC matrix containing a proton transfer agent. These pH sensors provide internally-referenced calibration-free operation, both in ratiometric intensity and lifetime-based detection modes. Sensor development included optimization of the indicator dye and its photophysical characteristics, screening of different proton transfer agents to minimize sensor toxicity, tuning of the protonation range and pKa, long-term storage stability and response time studies. Optimised pH sensor coatings were then deposited on plastic substrates (96-well microplates) and used for real-time monitoring of Extracellular Acidification Rate (ECAR) for cultured cancer cells and 3D spheroid structures on standard laboratory equipment (multi-label plate reader and confocal FLIM microscope). The advanced pH sensors tailored for use with biological samples have high potential for cell analysis and related applications.

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Genomic and Kinetic Modeling Involving Nanoparticle-Mediated Delivery of a Novel Chitinase Enzyme to Outpace Tuta absoluta Damage

Ispirli, Y.; Can, A.; Kececi, M.; Sahin, S. S.; Ayan, S. E.; Baysal, O.

2026-06-23 biochemistry 10.64898/2026.06.23.733920 medRxiv
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The tomato leafminer, Tuta absoluta, poses a severe global agricultural threat due to its rapid leaf-mining behavior and swift development of resistance to conventional chemical pesticides. While microbial chitinases are potent biopesticides, their field efficacy is limited by environmental degradation and the short exposure window before larvae penetrate leaf tissues. This study evaluates a stimuli-responsive, controlled-release nanobiopesticide system utilizing a novel chitinase from newly characterized Serratia marcescens GBS19. A 61.1 kDa chitinase (GBS19_ChiA) was heterologously expressed in Escherichia coli and purified to a specific activity of 215.01 U/mg. The enzyme was immobilized onto starch-coated silica nanoparticles designed for target-triggered release via host alpha-amylase. Genomic profiling and R-based kinetic modeling were integrated to evaluate the efficacy of purified and immobilized forms against T. absoluta. Immobilization enhanced thermal and pH stability, with the nanocarrier maintaining 85% activity over 10 weeks. In larval bioassays, immobilization increased mortality from 21.9% to 59.4% (5000 U/mL) by day 3, reaching 62.5% by day 6. Genomic analysis identified an expansive secretome and a Type VI Secretion System (T6SS), characterizing GBS19 as a multi-pronged pathogen. Kinetic modeling established that while immobilized enzymes are effective, the 2.5-hour exposure time on T. absoluta requires the synergistic action of chitinases (ChiA/B/C) to reach the lethal desiccation threshold before larvae establish protective mines. Starch-coated silica nanoparticles significantly improve chitinase stability and delivery. However, overcoming the rapid penetration of T. absoluta necessitates a whole-cell or multi-enzyme synergistic approach to outpace larval behavioural defences.

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Species-dependent antifungal profiles reveal stronger yeast inhibition by chitosan than by a sulfate-containing polysaccharide-rich extract from Jania adhaerens

Valverde-Urrea, M.; Defez-Perez, J.; Colom-Valiente, M. F.; Terradas-Fernandez, M.; Lopez-Llorca, L. V.

2026-07-21 microbiology 10.64898/2026.07.21.739751 medRxiv
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Yeast infections are becoming an increasing public health concern, mainly due to the spread of opportunistic species and the emergence of strains resistant to commonly used antifungal drugs. Marine resources are a promising source of bioactive compounds, including polysaccharides and other biopolymers with potential antifungal applications. In this study, a sulfate-containing polysaccharide-rich extract was obtained from the red alga Jania adhaerens and chemically characterized. Its antifungal activity was compared with that of a commercial chitosan formulation against clinically relevant yeasts, including species of Candida, Cryptococcus, 'Clavispora, Naganishia and Trichosporon. Growth kinetics were monitored in liquid medium over 24 h, and antifungal activity was evaluated through growth rate analysis, growth inhibition at 20 h and susceptibility clustering. The polysaccharide extract showed moderate but consistent growth inhibition, with the strongest effects observed at 5 mg mL-1. Maximum growth inhibition reached 60.9% in Cryptococcus deuterogattii and 59.8% in Candida albicans, although no complete inhibition was observed within the tested concentration range. In contrast, chitosan showed a stronger antifungal effect, with minimal inhibitory concentration (MIC) values between 10 and 20 {micro}g mL-1 in several species and maximum inhibition values above 80% in the most susceptible yeasts. However, C. albicans showed marked resistance to chitosan, with inhibition below 12%. K-means clustering confirmed distinct susceptibility profiles between treatments, supporting a species-dependent response. Overall, these results highlight marine-derived biopolymers as promising antifungal candidates and show that chitosan and algal sulphated polysaccharides produce distinct, species-dependent antifungal profiles.

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Layered double hydroxide nanoparticles induce composition-dependent cytotoxic and phenotypic effects in mammalian cells

Ferreira, A. L.; Cardoso, L. P.; Moraes-Lacerda, T.; dos Santos, L. E.; Gama, L. I. L. M.; de Araujo, W. R.; de Jesus, M. B.

2026-07-29 cell biology 10.64898/2026.07.28.741015 medRxiv
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Layered double hydroxides (LDHs) are increasingly explored for agricultural, environmental, and biodelivery applications, but their composition-dependent effects on mammalian cells remain insufficiently defined. Here, we synthesized Al-Ni, Al-Co, and Al-Cu LDH nanoparticles and evaluated their physicochemical properties and biological responses across exposure-relevant mammalian cell models. The formulations showed hydrodynamic diameters of approximately 200-300 nm, moderate dispersity, strongly positive surface charge, and characteristic lamellar LDH features. Cytotoxicity was assessed using MTT, Calcein-AM, and Hoechst-PI assays in HaCaT, A549, and HT-29 cells, representing dermal, pulmonary, and intestinal exposure contexts, together with NIH/3T3 fibroblasts as a sensitive comparative model. LDH toxicity was strongly dependent on metal composition and cell type, with an overall trend of Al-Cu > Al-Co > Al-Ni and more pronounced cytotoxic effects in A549 and HT-29 cells. To detect cellular perturbations beyond overt viability loss, we applied high-content imaging using Live Cell Painting. Multiparametric single-cell profiling revealed composition- and dose-dependent alterations in acidic vesicle organization, nuclear texture, and cytoplasmic granularity. Notably, phenotypic deviations were detected at concentrations below those producing measurable effects in conventional viability assays, and linear discriminant analysis separated the phenotypic signatures induced by the three LDH formulations. Together, these findings show that LDH biological activity cannot be generalized across metal compositions and that high-content phenotypic profiling provides added sensitivity for detecting early cellular perturbations. This integrated approach supports composition-aware nanosafety evaluation and may inform the safer development of LDH-based technologies for agricultural and biotechnological applications.

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Copper oxide nanoparticles function as antineoplastic agents in uterine cancer cell lines

Berezowitz, J. D.; Rowlands, C. E.; Mehanna, L. E.; Knicely, B. G.; Goellner, E. M.; Givens, B. E.

2026-06-10 bioengineering 10.64898/2026.06.07.729888 medRxiv
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Cancer of the uterine corpus is the fourth leading cancer and the fifth leading cause of cancer-related death in women in the United States. Chemotherapeutic resistance, specifically platinum-resistance, contributes to this problem. Therefore, an alternative treatment regimen is required. Using inorganic copper oxide nanoparticles (CuO NPs), we evaluated cancer cell responses indicative of anti-neoplastic activity. CuO NPs were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), dynamic light scattering (DLS) and laser Doppler velocimetry (LDV). The nanoparticles were rod-like and had a diameter of 70 {+/-} 30 nm and a copper content ranging from 77% - 82.6%. The hydrodynamic diameter and the zeta potential significantly decreased with more particles in solution. These materials were also used in four endometrial cancer cell lines and one cervical cancer cell line to evaluate cell viability, apoptosis, migration, and reactive oxygen species. In endometrial cancer cell lines, the IC50 values ranged from 1.028 ug/mL in HEC-1A cells to 73.62 ug/mL in Ishikawa cells, indicating that different cells have vastly different responses to CuO NPs. The results also indicated cell line-dependent differences in apoptosis, oxidation potential, and migration. Further, the cervical cancer cell line was modified using CRISPR technology to highlight a common germline mutation that causes earlier onset and more aggressive cancer progression. These genetic mutations resulted in differences in a loss of redox potential without observable changes in apoptosis or migration. The results of these studies indicate that CuO NPs elicit effects dependent upon the stage of cancer. Anticipated long-term applications of these studies includes the potential as a target-specific anti-cancer agent, designed using knowledge at the interface of colloids and the tumor environment. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=111 SRC="FIGDIR/small/729888v1_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@1e0fe68org.highwire.dtl.DTLVardef@5e776dorg.highwire.dtl.DTLVardef@1f2aad6org.highwire.dtl.DTLVardef@add7fc_HPS_FORMAT_FIGEXP M_FIG C_FIG Copper oxide nanoparticles (CuO NPs) were characterized upon receipt using electron microscopy, elemental analysis, dynamic light scattering, laser Doppler velocimetry, and Fourier-transform infrared spectroscopy. These CuO NPs were exposed to HeLa cells with and without DNA mismatch repair deficiencies to assess the impacts on cancer cell migration, apoptosis, and redox potential.