bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/631788

Effect of structure in ionized albumin - based nanoparticle: Characterisation, Emodin interaction, and in vitro cytotoxicity

Siri, M.·Ruocco, M. J. F.·Achilli, E.·Pizzuto, M.·Delgado, J. F.·Ruysschaert, J. M.·Grasselli, M.·Alonso, S. d. V.
View original source ↗Export metadata ↓

Abstract

A {gamma}-irradiated bovine albumin serum based nanoparticle was characterised structurally, and functionally. The nanoparticle was characterised by A.F.M, D.L.S, zeta potential, T.E.M., gel-electrophoresis, spectroscopy (UV-Vis, Fluorescence, FT-IR, and CD). Its stability was studied under adverse experimental conditions: pH values, chaotropic agents, and ionic strength and stability studies against time were mainly carried out by fluorescence spectroscopy following the changes in the tryptophan environment in the nanoparticle. Its function was studied by the interaction of the NP with the hydrophobic drug Emodin was studied. The binding and kinetic properties of the obtained complex were tested by biophysical methods as well as its toxicity in tumour cells.\n\nAccording to its biophysics, the nanoparticle is a spherical nanosized vehicle with a hydrodynamic diameter of 70 nm. Data obtained describe the nanoparticle alone as nontoxic for cancer cell lines. When combined with Emodin, the bioconjugate proved to be more active on MCF-7 and PC-3 cancer cell lines than the nanoparticle alone. No haemolytic activity was found when tested against ex vivo red blood cells. The stability of the albumin nanoparticle is based on a competition between short-range attraction forces and long-range repulsion forces. The nanoparticle showed similar behaviour as albumin against pH while improving its stability in urea and tween 80. It was stable up to 15 days and presented no protein degradation in solutions up to 2 M salt concentration. Significantly, the albumin aggregate preserves the main activity-function of albumin and improved characteristics as an excellent carrier of molecules.\n\nGraphical Abstract\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC=\"FIGDIR/small/631788v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (44K):\norg.highwire.dtl.DTLVardef@154a680org.highwire.dtl.DTLVardef@7f32b2org.highwire.dtl.DTLVardef@d97fdeorg.highwire.dtl.DTLVardef@159ee36_HPS_FORMAT_FIGEXP M_FIG C_FIG

Source connections

Explore related subjects

biophysicsPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Siri, M., Ruocco, M. J. F., Achilli, E., Pizzuto, M., Delgado, J. F., Ruysschaert, J. M., Grasselli, M., Alonso, S. d. V.. 2019-05-08. Effect of structure in ionized albumin - based nanoparticle: Characterisation, Emodin interaction, and in vitro cytotoxicity. https://doi.org/10.1101/631788

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Frequency-Dependent Structural Responses of Amyloid-β Fibrils to Terahertz Pulses: A Nonequilibrium Molecular Dynamics Study

The abnormal aggregation of amyloid proteins into fibrils is closely associated with several neurodegenerative diseases, highlighting the importance of developing effective strategies to modulate fibril structural stability. Here, we employed nonequilibrium molecular dynamics(NEMD) simulations to examine the effects of intense terahertz-to-mid-infrared pulses on three amyloid fibrils (2LMP, 2MXU, and 5OQV), focusing on the combined effects of pulse frequency and electric-field strength. Frequency scans from 0.5 to 60 THz in 0.5 THz steps revealed frequency-dependent losses of {beta}-sheet content, with several common response patterns in these fibrils. Comparisons at 2, 23, 33, and 50 THz showed that pulse-induced changes in secondary structure differed from those in high-temperature controls. Hydrogen-bond analysis showed that total hydrogen-bond counts could partially recover even as interchain hydrogen bonds continued to decrease, with distinct responses among representative chain pairs. We therefore propose a two-threshold electric-field framework for fibril disruption: Eth1 describes the onset of structural perturbation, whereas Eth2 indicates persistent structural loss after the pulse. This framework offers a testable approach for characterizing amyloid structural responses to external fields, although the underlying energy-coupling mechanisms, quantitative thresholds, and long-term recovery require further validation. These findings may provide a theoretical basis for exploring external-field-based strategies to modulate protein aggregation.

biophysics↗
bioRxiv2026

Organised streaming of cerebrospinal fluid in the human third ventricle

Quasi-periodic pressure pulses associated with cardiac and respiratory activity generate reciprocating cerebrospinal fluid (CSF) motion in the human ventricles. Regular waves dominated by the cardiac cycle are overlaid with cycles of low-frequency respiratory waves, the latter to become stronger in forced breathing or even dominated by large successive flushes in NREM sleep. The present study investigates how such waves contribute to residual streaming within the human ventricles. Transient CFD simulations were performed in the third ventricle at varying parameters of frequency, stroke volume and wave-form asymmetry. Increasing the aqueduct peak Reynolds-number, either by small stroke volume and high frequency or large stroke volume at low frequency, transfers the flow from a reversible flow pattern to the formation of clear preferential pathways, alternating between the in- and outflow cycle. The resulting permanent streaming flux across the aqueduct relative to the mean oscillatory flow-rate, i.e. the dimensionless streaming ratio SR follows a rational saturation relation, SR [~] ReAq,peak/(C + ReAq,peak), demonstrating that increasing the peak aqueduct Reynolds number yields diminishing returns and bounds the relative contribution of residual inter-ventricular streaming. These findings demonstrate differences in hydrodynamic organisation in the third ventricle and highlight the importance of this organisation for intraventricular fluid exchange.

biophysics↗
bioRxiv2026

Amyloid stability and condensate material properties independently govern the hnRNPA2 condensate to fibril transition

hnRNPA2 is a component of cellular membraneless organelles many of which contain RNA and RNA-binding proteins (RBPs). RBPs frequently contain low-complexity domains (LCDs) that can also assemble into amyloid fibrils. Fibrils isolated from patients with frontotemporal lobar degeneration contain ordered segments of these LCDs and disease-associated mutations can enhance the homotypic interactions that promote aggregation. Although previous studies have largely examined the condensate-to-fibril transition by altering condensate stability, how amyloid structure governs this process remains poorly understood. Here, we show that the hnRNPA2 LCD forms a reproducible fibril fold and by combining structure-guided thermodynamic profiling, peptide design, mutagenesis and in vitro characterization under conditions with (two-phase) and without (one-phase) condensates, we define the molecular determinants of its assembly. We identify an aromatic triad within the fibril core that controls fibril formation kinetics and thermodynamic stability. Mutational analysis further reveals that condensate stability and fibril stability are largely independent. Finally, microrheology linked reduced condensate viscosity to faster fibril formation, supporting a role for condensate material properties in regulating aggregation kinetics. Together, these findings support a model in which the condensate-to-fibril transition is governed by the interplay between a disordered ''fuzzy coat'' and a fibril-forming aromatic triad within hnRNPA2. This work provides a structural framework for understanding how condensates can transition into amyloid assemblies.

biophysics↗