arXiv subjects

Jean-François Berret

Publications and source records attributed to Jean-François Berret.

At least 19 recordsLinked to original sources

arXiv2025

Massart iron oxide nanoparticles in mechanobiology

Magnetic nanoparticles (MNPs) derived from the Massart coprecipitation method have played a pioneering role in bridging materials science and biology. Their magnetic moment and nanoscale dimensions have long enabled applications in magnetic resonance imaging, targeted drug delivery, separation technologies, and hyperthermia. Beyond these well-established uses, a growing research direction has emerged at the interface of physics and biology: the application of MNPs in mechanobiology, the study of how mechanical forces regulate cellular and tissue functions. This review examines how Massart MNPs can be used to generate, transmit, and measure forces within living systems. Particular attention is given to interfacial control through advanced surface chemistries, which ensure colloidal stability, minimize toxicity, and preserve the nanoscale integrity of the particles. We also show that the robustness and scalability of Massart synthesis make it ideally suited to the production of biocompatible nanomaterials in quantities required for comprehensive biological studies. Two complementary approaches are discussed. The first exploits MNP assemblies that arise spontaneously within cells, in the form of endosomes. These compartments enable the application of controlled magnetic forces to study both the formation of reconstructed tissues and organoids, and their viscoelastic response. The second focuses on micrometric magnetic wires fabricated from MNPs, used in active microrheology to probe the cytoplasm of living cells over a wide frequency range. Together, these approaches illustrate how MNP assemblies can accurately quantify cellular and tissue mechanics, providing new opportunities for mechanobiological studies and enabling the development of novel readouts of cellular mechanics with potential diagnostic applications.

cond-mat.soft↗

arXiv2025

Cytoplasmic flow induced by a rotating wire in living cells: Magnetic rotational spectroscopy and finite element simulations

Recent studies have highlighted intracellular viscosity as a key biomechanical property with potential as a biomarker for cancer cell metastasis. In the context of cellular mechanobiology, magnetic rotational spectroscopy (MRS), which employs rotating magnetic wires of length\,! = 2-8 $μ$m to probe cytoplasmic rheology, has emerged as an effective method for quantifying intracellular viscoelasticity. This study examines microrheology data from three breast epithelial cell lines, MCF-10A, MCF-7, and MDA-MB-231, along with new data from HeLa cervical cancer cells. Here, MRS is combined with finite element simulations to characterize the flow field induced by wire rotation in the cytoplasm. COMSOL simulations performed at low Reynolds numbers show that the flow velocity is localized around the wire, and display characteristic dumbbellshaped profiles. For wires representative of MRS experiments in cells, the product of shear rate and cytoplasmic relaxation time (''$ with $ ~ 1 s) remains below unity, indicating that the flow occurs within the linear regime. This outcome confirms that MRS can reliably measure the zeroshear viscosity of the intracellular medium in living cells. This study also demonstrates that integrating MRS intracellular measurements with COMSOL simulations significantly improves the reliability of in vitro assessments of cytoplasmic mechanical properties.

cond-mat.soft↗

arXiv2025

Dual-Functional Cerium Oxide Nanoparticles with Antioxidant and DNase I activities to Prevent and degrade Neutrophil Extracellular Traps

Neutrophils play a central role in immunothrombosis through the formation of neutrophil extracellular traps (NETs), a process known as NETosis. Upon stimulation, neutrophils release decondensed chromatin structures enriched with proteolytic enzymes, which contribute to thrombus formation. NETosis is critically dependent on reactive oxygen species (ROS), making redox regulation a key point of intervention. The intrinsic redox cycling of cerium oxide nanoparticles (CNPs) imparts self-regenerating antioxidant properties suitable for modulating neutrophil-driven oxidative stress. To address both the prevention and clearance of NETs, we developed dual-functional CNPs conjugated with DNase I. These engineered nanoparticles were efficiently internalized by neutrophils, reduced intracellular ROS levels, and inhibited NETs formation. In addition, DNase I-functionalized CNPs degraded pre-formed NETs. This dual-action strategy offers a promising nanotherapeutic platform for mitigating NETs-associated thrombotic pathologies. Ongoing studies aim to enhance thrombus targeting and assess in vivo efficacy.

physics.bio-ph↗

arXiv2025

Characterization of atomization and delivery efficiency of exogenous surfactant in preterm infant lungs using an ex vivo respiratory model

Administration of pulmonary surfactant is crucial for the treatment of respiratory distress syndrome (RDS) in preterm infants. The aim of this study is to evaluate the potential of Curosurf atomization via the Endosurf device, a recently developed spray technology, as a promising approach for surfactant delivery in infants with RDS. A comprehensive analysis was performed to evaluate the physicochemical properties of atomized Curosurf, including its surface tension and rheology. The size distribution of Curosurf vesicles was also investigated. An ex vivo respiratory model based on rabbit lungs breathing through an instrumented hypobaric chamber representing the thorax of a preterm infant was developed to provide proof of concept for regional aerosol deposition of atomized Curosurf. The atomization of Curosurf with the innovative Endosurf device did not significantly alter surface tension, but reduced vesicle size and promoted homogeneous distribution of Curosurf in the lungs. Rheological measurements showed the viscoelastic complexity of atomized Curosurf. This preliminary study confirmed the promising potential of Curosurf atomization via the Endosurf device for the distribution of surfactant in the lungs of infants with RDS. These advances could help to improve the treatment of RDS in preterm infants and offer new perspectives for healthcare professionals and affected families.

physics.med-ph↗

arXiv2025

Magnetic Pillar Induced Poiseuille-like Flow in Microfluidic Channels with Viscous and Viscoelastic Fluids

Mucociliary clearance in mammals serves as the primary defense mechanism for removing particulate matter deposited in the pulmonary airways. Dysfunctions in this process are linked to serious respiratory diseases and can hinder effective drug delivery to the lungs. Microfluidic systems have emerged as a promising alternative for replicating lung functions in non-cellular physiological environments, offering a simpler and more controllable approach compared to in vivo and in vitro assays. Here we present a microfluidic platform featuring a closed-loop circular microchannel, integrating thousand 75 micrometer high magnetic pillars arranged in a square array. Made of polydimethylsiloxane and loaded with iron microparticles, the pillars are studied using scanning electron microscopy and magnetometry; their internal structure and bending response to a magnetic field are quantitatively analyzed. Using a combination of experimental data and finite element simulations, we found that the magnetic torque induced by permanent magnets dominates over magnetic force, generating fluid flow in the microchannel. Under the application of a rotating field, the time-dependent deflection of the pillars closely mimics the behavior of lung cilia, exhibiting alternating recovery phases and rapid whip-like movements. The velocity profiles of viscous and viscoelastic fluids are examined, and shown to display Poiseuille-type flow. By varying the viscosity of the fluids across four orders of magnitude, we identified a transition in propulsion regimes between viscous and elastic-driven flows. This active microfluidic platform offers a promising approach for modeling mucociliary clearance in drug delivery applications.

physics.flu-dyn↗

arXiv2024

Heterogeneity of tumor biophysical properties and their potential role as prognostic markers

Progress in our knowledge of tumor mechanisms and complexity led to the understanding of the physical parameters of cancer cells and their microenvironment, including the mechanical, thermal, and electrical properties, solid stress, and liquid pressure, as critical regulators of tumor progression and potential prognostic traits associated with clinical outcomes. The biological hallmarks of cancer and physical abnormalities of tumors are mutually reinforced, promoting a vicious cycle of tumor progression. A comprehensive analysis of the biological and physical tumor parameters is critical for developing more robust prognostic and diagnostic markers and improving treatment efficiency. Like the biological tumor traits, physical tumor features are characterized by inter-and intratumoral heterogeneity. The dynamic changes of physical tumor traits during tumor progression and as a result of tumor treatment highlight the necessity of their spatial and temporal analysis in clinical settings. This review focuses on the biological basis of the tumor-specific physical traits, the state-of-the-art methods of their analyses, and the perspective of clinical translation. The importance of tumor physical parameters for disease progression and therapy resistance, as well as current treatment strategies to monitor and target tumor physical traits in clinics, is highlighted.

physics.bio-ph↗

arXiv2024

Mixing order asymmetry in nanoparticle-polymer complexation and precipitation revealed by isothermal titration calorimetry

In recent years, there has been a renewed interest in complex coacervation, driven by concerted efforts to offer novel experimental and theoretical insights into electrostatic charge-induced association. While previous studies have primarily focused on polyelectrolytes, proteins or surfactants, our work explores the potential of using cerium (CeO2) and iron (γ-Fe2O3) oxide nanoparticles (NPs) to develop innovative nanomaterials. By combining various charged species, such as polyelectrolytes, charged neutral block copolymers and coated NPs, we study a wide variety of complexation patterns and compare them using isothermal titration calorimetry, light scattering and microscopy. These techniques confirm that the titration of oppositely charged species occurs in two steps: the formation of polyelectrolyte complexes and subsequent phase (or microphase) separation, depending on the system studied. Across all examined cases, the entropic contribution to the total free energy surpasses the enthalpic contribution, in agreement with counterion release mechanisms. Furthermore, our investigation reveals a consistent asymmetry in the reaction enthalpy associated with the secondary process, with exothermic profiles observed upon the addition of cationic species to anionic ones and endothermic profiles in the reverse case.

cond-mat.soft↗

arXiv2024

Cytoplasmic Viscosity is a Potential Biomarker for Metastatic Breast Cancer Cells

Cellular microrheology has shown that cancer cells with high metastatic potential are softer compared to non-tumorigenic normal cells. These findings rely on measuring the apparent Young modulus of whole cells using primarily atomic force microscopy. This study aims to explore whether alternative mechanical parameters have discriminating features with regard to metastatic potential. Magnetic rotational spectroscopy (MRS) is employed in the examination of mammary epithelial cell lines: MCF-7 and MDA-MB-231, representing low and high meta-static potential, alongside normal-like MCF-10A cells. MRS utilizes active micron-sized magnetic wires in a rotating magnetic field to measure the viscosity and elastic modulus of the cy-toplasm. All three cell lines display viscoelastic behavior, with cytoplasmic viscosities ranging from 10-70 Pa s and elastic moduli from 30-80 Pa. It is found that the tumorigenic MCF-7 and MDA-MB-231 cells are softer than the MCF-10A cells, with a twofold decrease in elastic modulus. To differentiate cells with low and high malignancy however, viscosity emerges as the more discriminating parameter, as MCF-7 exhibits a 5 times higher viscosity as compared to MDA-MB-231. These findings highlight the sensitivity of cytoplasmic viscosity to metastatic potential, suggesting its potential utility as a mechanical marker for malignant cancer cells.

physics.bio-ph↗

arXiv2023

Adsorption of fragrance capsules onto cellulose nano- and micro-cellulose fibers in presence of guar biopolymers

Fabric softeners are formulated to enhance textile softness and impart a pleasant scent. One of the most efficient technologies for controlled fragrance delivery onto fabrics involves encapsulating scent molecules in polymer capsules. Here, we investigate the adsorption of anionic fragrance cap-sules on cotton fabrics with the goal of reducing the reliance on palm-oil-derived surfactants. First, we employ 200 nm-cellulose nanocrystals (CNC) as a reliable model for cotton fibers. CNC enables us to explore interactions among various softener components, including surfactants, guar biopolymers, and fragrances, using physical chemistry techniques applied to bulk dispersions. The primary objec-tive is to elucidate the role of surfactant vesicles, the primary ingredient in textile conditioners, in the association between fragrance capsules and cotton. Secondly, we examine the influence of bi-opolymers present in a newly developed, environmentally friendly softener on this association. Our findings demonstrate that anionic fragrance capsules are deposited onto cotton microfibers in the presence of either cationic surfactants or guar biopolymers, driven by electrostatic interactions. Scanning electron microscopy confirms capsule adsorption on textile fibers when these cationic in-gredients are present. Understanding the interaction mechanisms between fragrance capsules and cotton fabrics, as well as the roles played by other softener components, can facilitate the design of more efficient and sustainable formulations.

cond-mat.soft↗

arXiv2023

Cerium oxide catalyzed disproportionation of hydrogen peroxide: a closer look at the reaction intermediate

Cerium oxide nanoparticles (CNPs) have recently gained increasing interest as redox enzyme-mimetics to scavenge the intracellular excess of reactive oxygen species, including hydrogen peroxide (H2O2). Despite the extensive exploration of CNP scavenging activity, there remains a notable knowledge gap regarding the fundamental mechanism underlying the CNP catalyzed disproportionation of H2O2. In this Letter, we present evidence demonstrating that H2O2 adsorption at CNP surface triggers the formation of stable intermediates known as ceriumperoxo complexes (Ce-O2 2-). The cerium-peroxo complexes can be resolved by Raman scattering and UV-Visible spectroscopy. We further demonstrate that the catalytic reactivity of CNPs in the H2O2 disproportionation reaction increases with the Ce(III) fraction. The developed approach using UV-Visible spectroscopy for the characterization of Ce-O2 2-complexes can potentially serve as a foundation for determining the catalytic reactivity of CNPs in the disproportionation of H2O2.

cond-mat.soft↗

arXiv2023

Effects of brake wear nanoparticles on the protection and repair functions of the airway epithelium

Long term exposure to particulate air pollution is known to increase respiratory morbidity and mortality. In urban areas with dense traffic most of these particles are generated by vehicles, via engine exhaust or wear processes. Non-exhaust particles come from wear processes such as those concerning brakes and their toxicity is little studied. To improve our understanding of the lung toxicity mechanisms of the nanometric fraction of brake wear nanoparticles (BWNPs), we studied whether these particles affect the barrier properties of the respiratory epithelium considering particle translocation, mucus production and repair efficiency. The Calu-3 cell line grown in two-compartment chambers was used to mimic the bronchial epithelial barrier. BWNPs detected by single-particle ICP-MS were shown to cross the epithelial tissue in small amounts without affecting the barrier integrity properties, because the permeability to Lucifer yellow was not increased and there was no cytotoxicity as assessed by the release of lactate-dehydrogenase. The interaction of BWNPs with the barrier did not induce a pro-inflammatory response, but increased the expression and production of MU5AC, a mucin, by a mechanism involving the epidermal growth factor receptor pathway. During a wound healing assay, BWNP-loaded cells exhibited the same ability to migrate, but those at the edge of the wound showed higher 5-ethynyl-2'-deoxyuridine incorporation, suggesting a higher proliferation rate. Altogether these results showed that BWNPs do not exert overt cytotoxicity and inflammation but can translocate through the epithelial barrier in small amounts and increase mucus production, a key feature of acute inflammatory and chronic obstructive pulmonary diseases. Their loading in epithelial cells may impair the repair process through increased proliferation.

physics.med-ph↗

arXiv2023

Synthesis of stable cerium oxide nanoparticles coated with phosphonic acid-based functional polymers

Functional polymers, such as poly(ethylene glycol) (PEG) terminated with a single phosphonic acid, hereafter PEGik-Ph are often applied to coat metal oxide surfaces during post synthesis steps, but are not sufficient to stabilize sub-10 nm particles in protein-rich biofluids. The instability is attributed to the weak binding affinity of post-grafted phosphonic acid groups, resulting in a gradual detachment of the polymers the surface. Here, we assess these polymers as coating agents using an alternative route, namely the one-step wet-chemical synthesis, where PEGik-Ph is introduced with cerium precursors during the synthesis. Characterization of the coated cerium oxide nanoparticles indicates a core-shell structure, where the cores are 3 nm cerium oxide and the shell consists of functionalized PEG polymers in a brush configuration. Results show that cerium oxide nanoparticles coated with PEG1k-Ph and PEG2k-Ph are of potential interest for applications as nanomedicine due to their high Ce(III) content and increased colloidal stability in cell culture media. We further demonstrate that the cerium oxide nanoparticles in the presence of hydrogen peroxide show an additional absorbance band in the UV-vis spectrum, which is attributed to Ce-O22- peroxo-complexes and could be used in the evaluation of their catalytic activity for scavenging reactive oxygen species.

cond-mat.soft↗

arXiv2023

N,N,N-Trimethyl chitosan as a permeation enhancer for inhalation drug delivery: interaction with a model pulmonary surfactant

N,N,N-Trimethyl chitosan (TMC), a biocompatible and biodegradable derivative of chitosan, is currently used as a permeation enhancer to increase the translocation of drugs to the bloodstream in the lungs. This article discusses the effect of TMC on a mimetic pulmonary surfactant, Curosurf, a low-viscosity lipid formulation administered to preterm infants with acute respiratory distress syndrome. Curosurf exhibits a strong interaction with TMC, resulting in the formation of aggregates at electrostatic charge stoichiometry. At nanoscale, Curosurf undergoes a profound reorganization of its lipid vesicles in terms of size and lamellarity. The initial micron-sized vesicles (average size 4.8 microns) give way to a froth-like network of unilamellar vesicles about 300 nm in size. Under such conditions, neutralization of the cationic charges by pulmonary surfactant may inhibit TMC permeation enhancer capacity, especially as electrostatic charge complexation is found at low TMC content. The permeation properties of pulmonary surfactant-neutralized TMC should then be evaluated for its applicability as a permeation enhancer for inhalation in the alveolar region.

q-bio.QM↗

arXiv2022

Comment on Bilayer aggregate microstructure determines viscoelasticity of lung surfactant suspensions by C.O. Ciutara and J.A. Zasadzinski, Soft Matter, 2021, 17, 5170-5182

For applications of pulmonary surfactant delivery to the lungs, the question of rheology of the existing clinical formulations is of upmost importance. Recently, Ciutara and Zasadsinky (Soft Matter, 2021, 17, 5170-5182) measured the rheological properties of Infasurf, Survanta and Curosurf, three of the most used pulmonary surfactant substitutes. This study revealed that these fluids are shear-thinning and characterized by a yield stress. The results obtained by Ciutara et al. on Curosurf differ from our results published in Colloids and Surfaces B: Biointerfaces, 2019, 178, 337-345 and in ACS Nano, 2020, 14, 466 - 475. In contrast, we found that Curosurf suspensions are viscous Newtonian or slightly shear-thinning fluids, with no evidence of yield stress. The purpose of this Comment is to discuss possible causes for the discrepancy between the two studies, and to suggest that for biological fluids such as surfactant substitutes, the microrheology technique of rotational magnetic spectroscopy (MRS) can provide valuable results.

cond-mat.soft↗

arXiv2022

Nanoparticle-Protein Interaction: Demystifying the Correlation Between Protein Corona and Aggregation Phenomena

Protein corona formation and nanoparticle aggregation have been heavily discussed over the last years since the lack of fine-mapping of these two combined effects has hindered the targeted delivery evolution and the personalized nanomedicine development. We present a multi-technique approach that combines Dynamic Light and Small-Angle X-ray Scattering techniques with cryo-Transmission Electron Microscopy in a given fashion that efficiently distinguishes protein corona from aggregates formation. This methodology was tested using 25-nm model silica nanoparticles incubated with either model proteins or biologically relevant proteomes (such as fetal bovine serum and human plasma) in buffers of low and high ionic strengths to precisely tune particle-to-protein interactions. In this work, we were able to differentiate protein corona, small aggregates formation, and massive aggregation, as well as obtain fractal information of the aggregates reliably and straightforwardly. The strategy presented here can be expanded to other particle-to-protein mixtures and might be employed as a quality control platform for samples that undergo biological tests.

cond-mat.soft↗

arXiv2022

Sol-gel transition induced by alumina nanoparticles in a model pulmonary surfactant

Inhaled airborne particles smaller than 100 nm entering the airways have been shown to deposit in significant amount in the alveolar region of the lungs. The interior of the alveoli is covered with a ~ 1 micron thick lining fluid, called pulmonary surfactant. Inhaled nanoparticles are susceptible to interact with the lung fluid and modify pulmonary functions. Here we evaluate the structural and rheological properties of the pulmonary surfactant substitute Curosurf which is administered to premature babies for the treatment of respiratory distress syndrome. Curosurf is considered a reliable model of endogenous pulmonary surfactant in terms of composition, structure and function. Using active microrheology based on magnetically actuated wires, we find that Curosurf dispersions exhibit a Newtonian behavior at lipid concentration from 0 to 80 g L-1, and that the viscosity follows the Krieger-Dougherty law observed for a wide variety of colloids. Upon addition of 40 nm alumina nanoplatelets, a significant change of the Curosurf rheology is noticed. The dispersions then enter a soft solid phase characterized by an infinite viscosity and a non-zero equilibrium elastic modulus. The sol-gel transition induced by the nanoparticles is interpreted as the result of the alumina/vesicle interaction, which are illustrated by transmission electron microscopy. It also suggests a potential toxicity associated with the modification of the lung fluid structural and dynamical properties.

cond-mat.soft↗

arXiv2021

Probing DNA-amyloid interaction and gel formation by active magnetic wire microrheology

Recent studies have shown that bacterial nucleoid-associated proteins (NAPs) can bind to DNA and result in altered structural organization and bridging interactions. Under spontaneous self-assembly, NAPs may form anisotropic amyloid fibers, whose effects are still more significant on DNA dynamics. To test this hypothesis, microrheology experiments on dispersions of DNA associated with the amyloid terminal domain (CTR) of the bacterial protein Hfq were performed using the technique of magnetic rotational spectroscopy (MRS). In this chapter, we survey this microrheology technique which is based on the remote actuation of magnetic wires embedded in a sample. MRS is interesting as it is easy to implement, and does not require complex procedures regarding data treatment. Pertaining to the interaction between DNA and amyloid fibers, it is found that DNA and Hfq-CTR protein dispersion behave like a gel, an outcome that suggests the formation of a network of amyloid fibers cross-linked with the DNA strands. In contrast, the pristine DNA and Hfq-CTR dispersions behave as purely viscous liquids. To broaden the scope of the MRS technique, we include theoretical predictions for the rotation of magnetic wires regarding the generic behaviors of basic rheological models from continuum mechanics, and we list the complex fluids studied by this technique over the past 10 years.

cond-mat.mtrl-sci↗

arXiv2021

Advanced eco-friendly formulations of guar biopolymer-based textile conditioners

Fabric conditioners are household products used to impart softness and fragrance to tex-tiles. They are colloidal dispersions of cationic double chain surfactants that self-assemble in vesicles. These surfactants are primarily derived from palm oil chemical modification. Reducing the content of these surfactants allows to obtain products with lower environmental impact. Such a reduction, without adverse effects on the characteristics of the softener and its performance, can be achieved by adding hydrophilic biopolymers. Here, we review the role of guar biopolymers modified with cationic or hydroxyl-propyl groups on the physicochemical properties of the formulation. Electronic and optical microscopy, dynamic light scattering, X-ray scattering and rheology of vesicles dispersion in absence and in presence of guar biopolymers are analyzed. Finally, the deposition of the new formulation on cotton fabrics is examined through scanning electron microscopy and a new protocol based on fluorescent microscopy. With this methodology it is possible to quantify the deposition of surfactants on cotton fibers. The results show that the approach followed here can facilitate the design of sustainable home-care products.

cond-mat.soft↗