Jean-Luc Putaux

Jean-Luc Putaux
French National Centre for Scientific Research | CNRS · Centre de Recherches sur les Macromolécules Végétales

PhD

About

287
Publications
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Publications

Publications (287)
Article
Full-text available
Twin-screw extrusion (TSE) is a recent strategy used to prepare nanocelluloses at high solid contents. However, various aspects of the mechanism of disintegration and the role of fiber pretreatment remain to be elucidated. Oxidized cellulose fibers with carboxyl contents (CCs) between 300 and 700 μmol·g⁻¹ were extruded in the presence of polyvinyl...
Article
Colloidal nanoparticles were prepared by aqueous self-assembly of amphiphilic β-cyclodextrins (βCDs) acylated on their secondary face with C14 chains to a total degree of substitution of 7.0, via a thermolysin-catalyzed transesterification process. The small-angle X-ray scattering pattern of the nanoparticles was consistent with a reverse hexagonal...
Article
Full-text available
Carbohydrate nanoparticles, both naturally derived and synthetic ones, have attracted scientific and industrial attention as high-performance renewable building blocks of functional materials. Electron microscopy (EM) has played a central role in investigations of their morphology and molecular structure, although the intrinsic radiation sensitivit...
Article
Chain-folded lamellar V-amylose single crystals were prepared by adding butan-1-ol to hot dilute aqueous solutions of native amylose. The base-plane electron and X-ray diffraction patterns recorded from hydrated specimens agreed with a P212121 space group and an orthorhombic unit cell. A molecular model resulting from an exhaustive search of helix...
Article
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Foodborne diseases caused by resistance of microorganisms to multiple antimicrobial agents have emerged as a major public health concern around the world. The search for potential antimicrobials has resulted in the emergence of metal nanoparticles for protection against these infections. In this study an eco-friendly and green approach was used to...
Article
Full-text available
Emulsion polymerization remains the most attractive method to produce waterborne dispersions for coatings and adhesives, thanks to the use of water as dispersion medium. The possibility to replace the surfactants necessary for the stabilization by biopolymers would make this polymerization route even more attractive to alleviate the shortcomings of...
Article
Pure granular amylose (AM) and pure granular amylopectin (waxy) starch (AP) granules have the high nutritional value in food industry. Effects of microwave treatment (400 W/g DW, 1–8 min) on the structure and properties of transgenic AM granules and AP granules were investigated in direct comparison. Microwave treatment, especially during the first...
Article
Ordered molecular self‐assembly of glycoamphiphiles has been regarded as an attractive, practical and bottom‐up approach to obtain stable, structurally well‐defined, and functional mimics of natural polysaccharides. This study describes a versatile and rational design of carbohydrate‐based hydrogelators through N , N’ ‐substituted barbituric acid‐m...
Article
Full-text available
Developing electrolyzers operating under neutral or near-neutral conditions with catalysts based only on earth-abundant metals is highly desirable with a view to reduce the cost of hydrogen production from water...
Article
The two ends of rodlike cellulose II nanocrystals (CNC-II) were regioselectively functionalized either with gold nanoparticles or thermosensitive polymer chains. In the first case, after the introduction of sulfur atoms...
Article
Rectangular V-amylose single crystals were prepared by adding racemic ibuprofen to hot dilute aqueous solutions of native and enzymatically-synthesized amylose. The lamellar thickness increased with increasing degree of polymerization of amylose and reached a plateau at about 7 nm, consistent with a chain-folding mechanism. The CP/MAS NMR spectrum...
Article
Full-text available
An experimental study of the ultrasonic compression moulding (UCM) to manufacture biobased composites made of semicrystalline starch powders and softwood fibres is described. The main objective was to assess the potential of using this fast and economical processing technique to elaborate a 100% biobased composite which might substitute more usual...
Article
Chitin nanocrystals (ChNCs) produced by hydrochloric acid hydrolysis of chitin were used as stabilizing agent for oil-in-water (O/W) emulsification of soybean oil (SO), acrylated soybean oil (ASO), and epoxidized soybean oil (ESO). The emulsion stability, droplet size, and rheology of the emulsion were found to be significantly affected by the oil...
Article
The breakdown and buildup mechanisms in concentrated cellulose nanocrystal (CNC) suspensions under shear and during relaxation upon cessation of shear were accessed by small-angle X-ray or light scattering combined with rheometry. The dynamic structural changes over nanometer to micrometer lengthscales were related to the well-known three-regime rh...
Article
A strategy to optimize the labeling of the reducing end of native cellulose nanocrystals (CNCs) with gold nanoparticles (AuNPs) was developed and used to investigate the arrangement of the elementary crystallites constituting these biosourced particles. First, CNCs pre-functionalized with thiosemicarbazide molecules were reacted with presynthesized...
Article
Chain-folded lamellar crystalline complexes of amylose with aliphatic diols were prepared and characterized by transmission electron microscopy as well as electron and X-ray diffraction. Four allomorphs were identified, depending on the complexing diol and crystallization conditions, that consisted of orthorhombic lattices of antiparallel 6- or 7-f...
Article
Emulsion polymerization provides a sustainable way to produce latex polymers for coatings and adhesives thanks to the use of water as a dispersion medium. This synthesis approach can be even more attractive if synthetic surfactant can be replaced by biobased solid particles as a stabilizer, through what is known as a “Pickering effect”. Herein, lat...
Article
Magnetic biopolymer hybrid nanoparticles have gained a lot of attention in the field of biomedical applications. Here we present the synthesis of hyaluronic acid (HA)-coated magnetic clusters of superparamagnetic nanoparticles. Firstly, the superparamagnetic magnetite nanoparticles coated with oleic acid were synthesized and characterized in terms...
Article
Abnormal carbohydrate structures known as polyglucosan bodies (PGBs) are associated with neurodegenerative disorders, glycogen storage diseases (GSDs), and aging. A hallmark of the GSD Lafora disease (LD), a fatal childhood epilepsy caused by recessive mutations in the EPM2A or EPM2B genes, are cytoplasmic PGBs known as Lafora bodies (LBs). LBs res...
Article
Nanocomposites based on thermoplasticized starch filled with cellulose nanofibrils (CNFs) were produced in a single step by twin-screw extrusion of corn starch granules, glycerol as a plasticizer, and oxidized cellulose fibers. The objective was to demonstrate the possibility to produce CNFs in situ during the processing of the nanocomposite when a...
Article
Artemisinin and its derivatives are currently recommended by World Health Organization for the treatment of malaria. Severe malaria requires a parenteral administration of artemisinin-based formulations. However, the effective use of artemisinin is limited by the pharmacokinetic characteristics of the drug (low water solubility, poor bioavailabilit...
Article
Full-text available
Starch granules that accumulate in the plastids of plants vary in size, shape, phosphate, or protein content according to their botanical origin. Depending on their size, the applications in food and nonfood industries differ. Being able to master starch granule size for a specific plant, without alteration of other characteristics (phosphate conte...
Article
Full-text available
Starch granule morphology is highly variable depending on the botanical origin. Moreover, all investigated plant species display intra-tissular variability of granule size. In potato tubers, the size distribution of starch granules follows a unimodal pattern with diameters ranging from 5 to 100 µm. Several evidences indicate that granule morphology...
Article
Full-text available
The effect of sonication on a highly concentrated commercial suspension of cellulose nanocrystals (CNCs) and the resulting rheological properties have been investigated. Rheology and structural analysis techniques (atomic force microscopy, small-angle X-ray scattering, transmission electron microscopy and dynamic light scattering) were used to char...
Article
Lamellar single crystals of V‐amylose were prepared from dilute aqueous solutions in the presence of selected bicyclic compounds. Transmission electron microscopy images as well as electron and X‐ray diffraction patterns revealed that two allomorphs containing 7‐fold amylose single helices were formed depending on the complexing agent. On the one h...
Article
Novel biocomposites were fabricated using preforms of unmodified starch powder and wood pulp fibers. Stacks of preforms were consolidated using thermo-compression (TCM) and ultrasonic compression moldings (UCM). The characterization of the microstructure of the biocomposites showed that TCM enabled a better preservation of the crystallinity of star...
Article
Diatoms are a major phylum of phytoplankton biodiversity and a resource considered for biotechnological developments , as feedstock for biofuels and applications ranging from food, human health or green chemistry. They contain a secondary plastid limited by four membranes, the outermost one being connected with the endoplasmic reticulum (ER). Upon...
Article
We present here the grafting of thermoresponsive polyetheramines at the reducing ends of cellulose nanocrystals (CNCs) using a two-step protocol involving an end carboxylation followed by a peptide coupling with the primary amine moiety of the polyetheramine. In aqueous suspensions these end-modified CNCs became associated by their derivatized tips...
Article
Full-text available
Chlamydomonas reinhardtii represents an ideal model microbial system to decipher starch metabolism. In this green algae, in cells growing in photosynthetic conditions, starch mainly accumulates as a sheath surrounding the pyrenoid while in cells subjected to a nutrient starvation, numerous starch granules are filling up the plastid stroma. The mech...
Article
Full-text available
Transmission electron microscopy (TEM) has played a significant role in the characterization of cellulosic materials, especially the so-called “nanocelluloses” (nanofibers and nanocrystals), from visualizing nanoscale morphologies to identifying crystal structures. With scientific and industrial interest in nanocelluloses rapidly increasing, this t...
Article
Full-text available
Following the first electron micrographs of cotton in 1940, the development of transmission electron microscopy applied to native cellulose has been evolving in a series of successive advances. At first, faced with the weak contrast of the early images, the operators had to use specific electron-dense contrasting agents to reveal the ultrastructure...
Article
Full-text available
Starch granules that accumulate in the plastids of plants vary in size, shape, phosphate, or protein content according to their botanical origin. Depending on their size, the applications in food and nonfood industries differ. Being able to master starch granule size for a specific plant, without alteration of other characteristics (phosphate conte...
Article
In vitro polymerization of β-mannans is a challenging reaction due to the steric hindrance confered by the configuration of mannosyl residues and the thermodynamic instability of the β-anomer. Whatever the approach used to date – whether chemical, or enzymatic with glycosynthases and mannosyltransferases – pure β-1,4-mannans have never been synthes...
Article
The periodate oxidation of microfibrillated cellulose followed by a reduction treatment was implemented to produce a new type of sterically-stabilized cellulosic nanorodsnanocrystals, which were characterized at the molecular and colloidal length scales. Solid-state NMR data showed that these treatments led to objects consisting of native cellulose...
Article
An efficient nanocomposite anode material for the oxygen-evolution reaction (OER) based on nickel oxide nanoparticles entrapped into a polypyrrole matrix has been readily synthesized by an all electrochemical procedure. Examples...
Article
Full-text available
Nanocellulose with a morphology ranging from long flexible to rod-like fibrils were produced via periodate oxidation route followed by reductive treatment with NaBH4 of never-dried eucalyptus pulp. The effect of the aldehyde content on the size and morphology of the resulting nanocellulose was studied by preparing three samples with 450, 830 and 14...
Article
The crystallization of amylose from dilute solutions in the presence of a series of linear saturated fatty acids (C3 to C20) was investigated by varying the fatty acid concentration, crystallization temperature and solvent composition (DMSO:water in various ratios). The morphology and structure of the resulting model lamellar crystals were characte...
Preprint
Full-text available
The initiation of starch granule formation is still poorly understood. However, soluble starch synthase 4 (SS4) appears to be a major component of this process since it is required to synthetize the correct number of starch granules in the chloroplasts of Arabidopsis thaliana plants. A yeast-2-hybrid screen allowed the identification of several put...
Article
Full-text available
Statement of significance: In this paper, we propose a new approach to assess the mineral properties of bone at the individual nanocrystal level, a daunting challenge for decades. We use a modified Transmission Electron Microscopy acquisition mode to perform an Automated Crystal Orientation Mapping (ACOM-TEM) by analyzing electron diffraction patt...
Article
Rubber materials with well-dispersed fillers and large mechanical reinforcement have been obtained by melt-processing a diene elastomer matrix and tailored nanocellulose powders having both a high specific surface area and a modified interface. Such filler powders with a specific surface area of 180 m2 g-1 and 100 m2 g-1 have been obtained by freez...
Article
The potential use of polyester polymeric nanoparticles (NPs) as drug nanocarriers is well-documented. Nevertheless, structural changes due to hydrophobic drug loading and release have been rarely explored. Herein, we have used static and dynamic light scattering (SDLS), small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and...
Article
The inline coupling of the field-amplified sample injection (FASI) to Taylor dispersion analysis (TDA) was used to characterize low-UV absorbing carboxylated silica nanoparticles (cNPs). The hydrodynamic diameters (Dh) were measured by using a commercial capillary electrophoresis instrument. The proposed methodology did not require any complicated...
Article
New α(1 → 2) or α(1 → 3) branched dextrans with high molar masses and controlled architecture were synthesized using a dextransucrase and branching sucrases. Their molecular structure, solubility, conformation, film-forming ability, as well as their thermal and mechanical properties were determined. These new dextrans present structures with low de...
Article
Background: Curcumin (CUR) has properties that can be useful for the treatment of Alzheimer's disease. Such properties are the inhibition of amyloid-β-protein (Aβ) aggregation, Aβ-induced inflammation, and activities of β-secretase and acetylcholinesterase. However, previous studies have revealed that CUR exhibited low bioavailability and difficul...
Article
A series of β-cyclodextrin (βCD) amphiphilic derivatives with varying degree of substitution was prepared by acylating βCDs on their secondary face using thermolysin to catalyze the transesterification. After dissolution in acetone, the βCD-Cn derivatives (n = 8, 10, 12, 14) were nanoprecipitated in water where they self-organized into structured p...
Chapter
Polarized Raman spectroscopy (PRS) and synchrotron X-ray microdiffraction were used to determine the local orientation of crystalline regions in giant starch granules extracted from bulbs of tulip and the orchid Phajus grandifolius. Starch granules can be described as distorted spherulites composed of concentric growth rings in which molecules are...
Chapter
One major challenge of nanomedicine is to design nanocarriers that deliver active compounds to a target site, at a sufficient concentration and without premature degradation, in order to maximize the efficiency of the substance while limiting secondary effects. In this context, we have developed colloidal nanovectors based on cyclodextrin (CD) amph...
Chapter
Amylose, a mostly linear homopolymer of α(1,4)-D-glucose extracted from native starch, has the ability to form crystalline inclusion compounds with a large variety of small molecules. In these crystallosolvates, the so-called “V-amylose” occurs in the form of single helices and the ligands can be located inside the helices, in-between or both [Lour...
Article
Full-text available
Soft mesoporous hierarchically structured particles were created by the self-assembly of an amphiphilic deep cavitand cyclodextrin βCD-nC10 (degree of substitution n = 7.3), with a nanocavity grafted by multiple alkyl (C10) chains on the secondary face of the βCD macrocycle through enzymatic biotransesterification, and the nonlamellar lipid monoole...
Article
In this work, polarized Raman spectroscopy (PRS) was used to determine orientation maps of crystallites present in Phajus grandifolius starch granules based on the anisotropic response of the glycosidic Raman band at 865 cm−1. The response of this band was preliminarily evaluated using model A-amylose crystals as standard. The A‐amylose crystals or...
Article
The deconstruction of the hierarchical structure of cellulose results in the production of cellulose nanofibrils (CNFs). CNFs are commonly obtained by grinding and high-pressure homogenization processes and both treatments can be simultaneously used. Nevertheless, the influence of a two-stage high pressure homogenization of previously ground CNFs o...
Article
Full-text available
In this study, thermo-compression molding was used to fabricate bulk materials from native starch powder. The objective was to determine the process parameters that enabled the welding of starch granules while preserving their crystallinity. The effects of forming parameters such as temperature, compression stress, and water content on the microstr...
Article
Full-text available
At variance with the starch accumulating plants and most of the glycogen-accumulating cyanobacteria, Cyanobacterium sp. CLg1 synthesizes both glycogen and starch. We now report the selection of a starchless mutant of this cyanobacterium that retains wild-type amounts of glycogen. Unlike other mutants of this type found in plants and cyanobacteria,...
Article
Full-text available
Cellulose nanofibrils (NFCs) are slender nanoparticles with outstanding mechanical properties that are used to enhance the mechanical properties of polymer nanocomposites and fabricate dense and transparent nanopapers. However, the reinforcement effect of these nanoparticles is not as efficient for the elastic properties as expected by the classica...