pH-Dependent Adsorption of Human Serum Albumin Protein on a Polystyrene-Block-Poly(acrylic acid)-Coated PVDF Membrane.

This study reports the investigation of human serum albumin (HSA) adsorption on a poy-styrene-block-poly(acrylic acid) (PS-b-PAA)-coated PVDF membrane, which is a potential smart material for biomedical applications. First, copolymer coating on the membrane surface was successfully performed, due to the hydrophobic interaction of the PS anchoring group with the PVDF membrane. This was confirmed by Fourier transform infrared spectroscopy (FTIR) characterization of the membrane.

Dopamine-Induced Surface Zwitterionization of Expanded Poly(tetrafluoroethylene) for Constructing Thermostable Bioinert Materials.

Although energy-demanding, the surface modification of polytetrafluoroethylene (PTFE) for biomedical applications is mandatory to mitigate irreversible biofouling that occurs whenever PTFE comes into contact with biological fluids. Here, we propose to take advantage of the adhesive properties of dopamine (DA) and of the antifouling ability of various zwitterionic monomers (sulfobetaine methacrylate (SBMA), sulfobetaine methacrylamide (SBAA), sulfobetaine acrylamide (SBAA'), and 4-vinylpyridine propylsulfobetaine (4VPPS)) and form antifouling coatings by copolymerization on the surface of expanded PTFE membranes. This simple, low-energy, and one-step coating procedure arises in significant biofouling mitigation.

In vivo magnetic resonance spectroscopy in the brain of Cdkl5 null mice reveals a metabolic profile indicative of mitochondrial dysfunctions.

Mutations in the X-linked CDKL5 gene cause CDKL5 deficiency disorder (CDD), a severe neurodevelopmental condition mainly characterized by infantile epileptic encephalopathy, intellectual disability, and autistic features. The molecular mechanisms underlying the clinical symptoms remain largely unknown and the identification of reliable biomarkers in animal models will certainly contribute to increase our comprehension of CDD as well as to assess the efficacy of therapeutic strategies. Here, we used different Magnetic Resonance (MR) methods to disclose structural, functional, or metabolic signatures of Cdkl5 deficiency in the brain of adult mice.

Pearl-necklace assembly of human serum albumin with the poly(acrylic acid) polyelectrolyte investigated using small angle X-ray scattering (SAXS).

In this comprehensive study, the interaction of human serum albumin (HSA) with poly(acrylic acid) (PAA) was explored using small angle X-ray scattering (SAXS) combined with chromatography. The results revealed the formation of a complex between HSA macromolecules and PAA chains but solely under some specific conditions of the ionic strength and pH of the medium. In fact, this binding was found to take place only at pH close to 5 and at low ionic strength (0.

Neurochemical and Ultrastructural Characterization of Unmyelinated Non-peptidergic C-Nociceptors and C-Low Threshold Mechanoreceptors Projecting to Lamina II of the Mouse Spinal Cord.

C-nociceptors (C-Ncs) and non-nociceptive C-low threshold mechanoreceptors (C-LTMRs) are two subpopulations of small unmyelinated non-peptidergic C-type neurons of the dorsal root ganglia (DRGs) with central projections displaying a specific pattern of termination in the spinal cord dorsal horn. Although these two subpopulations exist in several animals, remarkable neurochemical differences occur between mammals, particularly rat/humans from one side and mouse from the other. Mouse is widely investigated by transcriptomics.

Healing kinetics of diabetic wounds controlled with charge-biased hydrogel dressings.

The present study investigates the properties and use as wound-dressing materials of hydrogels made of negatively charged 3-sulfopropyl methacrylate (SA) and positively charged [2-(methacryloyloxy)ethyl]trimethylammonium (TMA) to form poly(SA-co-TMA) gels with/without a charge bias. Their actual chemical compositions were ascertained by XPS which revealed a fair control of the final gel composition obtained from the initial molar ratio in the reaction solution. Zeta potential measurements confirmed the controlled charge bias on which swelling ratio was found to strongly depend, i.

Bioinspired Pseudozwitterionic Hydrogels with Bioactive Enzyme Immobilization via pH-Responsive Regulation.

Hydrogels are hydrated networks of flexible polymers with versatile biomedical applications, and their resistance to nonspecific protein adsorption is critical. On the other hand, functionalization with other biomacromolecules would greatly enhance their biotechnological potential. The aim of this research is to prepare low fouling hydrogel polymers for selective protein immobilization.

Self-Cleaning Interfaces of Polydimethylsiloxane Grafted with pH-Responsive Zwitterionic Copolymers.

Self-cleaning surfaces allow the reversible attachment and detachment of microorganisms which show great promise in regards to their reusability as smart biomaterials. However, a widely used biomaterial such as polydimethylsiloxane (PDMS) suffers from high biofouling activity and hydrophobic recovery that results in decreased efficiency and stability. A current challenge is to modify and fabricate self-cleaning PDMS surfaces by incorporating antifouling and pH-sensitive properties.

Phosphorylation of histone H2AX in the mouse brain from development to senescence.

Phosphorylation of the histone H2AX (γH2AX form) is an early response to DNA damage and a marker of aging and disease in several cells and tissues outside the nervous system. Little is known about in vivo phosphorylation of H2AX in neurons, although it was suggested that γH2AX is an early marker of neuronal endangerment thus opening the possibility to target it as a neuroprotective strategy. After experimental labeling of DNA-synthesizing cells with 5-bromo-2-deoxyuridine (BrdU), we studied the brain occurrence of γH2AX in developing, postnatal, adult and senescent (2 years) mice by light and electron microscopic immunocytochemistry and Western blotting.

Post-natal development of the Reeler mouse cerebellum: An ultrastructural study.

Reelin, an extracellular protein promoting neuronal migration in brain areas with a laminar architecture, is missing in the Reeler mouse (reelin(-/-)). Several studies indicate that the protein is also necessary for correct dendritic outgrowth and synapse formation in the adult forebrain. By transmission electron microscopy, we characterize the development and synaptic organization of the cerebellar cortex in Reeler mice and wild type control littermates at birth, postnatal day (P) 5, 7, 10 and 15.

The galactocerebrosidase enzyme contributes to maintain a functional neurogenic niche during early post-natal CNS development.

We report a novel role for the lysosomal galactosylceramidase (GALC), which is defective in globoid cell leukodystrophy (GLD), in maintaining a functional post-natal subventricular zone (SVZ) neurogenic niche. We show that proliferation/self-renewal of neural stem cells (NSCs) and survival of their neuronal and oligodendroglial progeny are impaired in GALC-deficient mice. Using drugs to modulate inflammation and gene transfer to rescue GALC expression and activity, we show that lipid accumulation resulting from GALC deficiency acts as a cell-autonomous pathogenic stimulus in enzyme-deficient NSCs and progeny before upregulation of inflammatory markers, which later sustain a non-cell-autonomous dysfunction.

Mass transfer in a membrane aerated biofilm.

We present experimental results of mass transfer of a non reactive tracer gas (neon) measured in aerobic heterotrophic biofilm developed from activated sludge. Biofilms are grown in various hydrodynamic conditions and the effective diffusivity is used to quantify the mass transfer through the biofilm. Beyond some cross-flow conditions, the effective diffusivity through the biofilm seems larger than in the bulk.

Context-dependent toxicity of amyloid-β peptides on mouse cerebellar cells.

Alzheimer's disease (AD) is the major cause of dementia in old people. AD pathology is characterized by amyloid-β (Aβ) deposits in several regions of the brain, and links have been hypothesized between Aβ toxicity and apoptosis. Cerebellar granule cells (CGCs) have been widely used as in vitro tools for molecular studies correlating apoptosis with AD, although the cerebellum is a relatively spared area of the brain in vivo.

Colloidal surface interactions and membrane fouling: investigations at pore scale.

In this paper, we examine the contributions of colloidal surface interaction in filtration processes. In a first part, we describe the way surface interactions affect the transport of colloidal particles or macromolecules towards a membrane, and its theoretical description. The concept of critical flux is introduced and linked to particle-membrane wall and particle-particle surface interactions.

Effects of ionic strength on bacteriophage MS2 behavior and their implications for the assessment of virus retention by ultrafiltration membranes.

Bacteriophage MS2 is widely used as a surrogate to estimate pathogenic virus elimination by membrane filtration processes used in water treatment. Given that this water technology may be conducted with different types of waters, we focused on investigating the effects of ionic strength on MS2 behavior. For this, MS2 was analyzed while suspended in solutions of various ionic strengths, first in a batch experiment and second during membrane ultrafiltration, and quantified using (i) quantitative reverse transcriptase PCR (qRT-PCR), which detects the total number of viral genomes, (ii) qRT-PCR without the RNA extraction step, which reflects only particles with a broken capsid (free RNA), and (iii) the PFU method, which detects only infectious viruses.

[Removal of bisphenol A and tetrabromobisphenol A membrane by nanofiltration from water source].

The removal efficiency of BPA and TBBPA by nanofiltration membrane Desal 5 DK has been investigated with a lab-scale dead-end filtration module and the role of adsorption of two molecules on membrane was also explored to understand the filtration mechanism. The results showed that the R(obs) of BPA decreased from 89% to 47% as the accumulated adsorption quantity of BPA onto the membrane increased to 30 microg x m(-2). The high BPA concentration in adsorption layer caused the water flux decline especially at high pressure.

Neural-specific inactivation of ShcA functions results in anatomical disorganization of subventricular zone neural stem cell niche in the adult brain.

Shc(s) family of adaptor molecules has been implicated in several physiological functions. In particular, our previous studies have shown major roles in the mechanisms that control the transition from proliferating neural stem cells (NSCs) to postmitotic neurons in the mammalian brain. In the adult brain, ShcA expression is mainly restricted to a subpopulation of cells in the subventricular zone (SVZ) neurogenic area, enlightening a potential role for this molecule in the establishment/maintenance of this adult NSC niche.

Whey protein fractionation: isoelectric precipitation of alpha-lactalbumin under gentle heat treatment.

The selective precipitation of alpha-lactalbumin (alpha-LA) at a pH around its isoelectric point (4.2) under heat treatment is the basis for a fractionation process of whey proteins. In these conditions, beta-lactoglobulin remains soluble, whereas bovine serum albumin and immunoglobulins co-precipitate.

Filtration method characterizing the reversibility of colloidal fouling layers at a membrane surface: analysis through critical flux and osmotic pressure.

A filtration procedure was developed to measure the reversibility of fouling during cross-flow filtration based on the square wave of applied pressure. The principle of this method, the apparatus required, and the associated mathematical relationships are detailed. This method allows for differentiating the reversible accumulation of matter on, and the irreversible fouling of, a membrane surface.

Removal of bisphenol A by a nanofiltration membrane in view of drinking water production.

The efficiency with which a nanofiltration membrane (Desal 5 DK) removes bisphenol A (BPA) was investigated, together with the mechanisms involved. Whereas high retention (>90%) was obtained at the beginning of the filtration, the observed retention coefficient (R(obs)) decreased to around 50% when the membrane became saturated, due to adsorption of BPA onto the membrane structure. The presence of ions (Na+, Cl-) affects the R(obs), this effect being attributed to a change in BPA hydrodynamic radius.