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Comparison of different strategies based on β-casein dynamics toencapsulate curcumin in casein micelles 
Auteur(s): Bahri Asma, Martin Fernandez M., Gergely C., Marchesseau Sylvie, Chevalier-Lucia Dominique
(Article) Publié:
Food Hydrocolloids, vol. 173 p.112258 (2025)
Ref HAL: hal-05370839_v1
DOI: 10.1016/j.foodhyd.2025.112258
Exporter : BibTex | endNote
Résumé: Casein micelles (CM) are colloidal phospho-protein-mineral complexes naturally present in milk. Cooling inducesβ-casein dissociation from CM. The aim of the present research is to improve curcumin encapsulation in β-casein depleted CM. This study proposes an extraction and separation process including cooling, low acidification (pH 5.8) and membrane filtration at a pilot scale allowing a removal of 45 ±5 % of β-casein fraction from CM.Special care was taken to preserve the CM integrity. Investigation of the depleted CM topography by atomic force microscopy (AFM) reveals a swelling of the micellar structure with a mean width of 193 ±10 nm and a mean height of 80 ±5 nm. Concurrently, exploration of the elastic properties displays a stiffer nanomechanicalsignature compared to native CM, with a mean elasticity modulus of 195 ±17 kPa. The β-caseins extracted from CM were bound to curcumin prior to their encapsulation in depleted CM. This new encapsulation strategy was compared to two other methods, and the results show that it significantly increases the binding efficiency of curcumin to CM.
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Probing the role of telopeptides in collagen fibrillogenesis by Second Harmonic Scattering
Auteur(s): De Lizaraga J., Martin Fernandez M., Salmon Estelle, Cloitre T., Gergely C., Jonin C.
(Article) Publié:
Journal Of Physical Chemistry B, vol. 129 p.9020-9029 (2025)
Ref HAL: hal-05343498_v1
DOI: 10.1021/acs.jpcb.5c02016
Exporter : BibTex | endNote
Résumé: Collagen, the primary structural protein in the extracellular matrix, plays a critical role in tissue architecture and mechanical integrity. This study investigates the structural and nonlinear optical properties of atelocollagen (Acol) and telocollagen (Tcol) in response to pH variations using Second Harmonic Scattering (SHS), polarization-resolved SHS (P-SHS), and Atomic Force Microscopy (AFM). AFM imaging revealed distinct morphological differences, with Acol forming wavy, non-cross-linked, and randomly arranged fibers, while Tcol exhibited a more interconnected, mesh-like fibrillar network. SHS and P-SHS measurements further confirmed these differences, indicating significant variations in hyperpolarizability and depolarization ratio (DR) between Acol and Tcol. The results suggest that telopeptides play a crucial role in collagen fibrillogenesis, influencing molecular symmetry and optical responses. The observed differences in nonlinear optical properties highlight the potential of SHS as a powerful tool for characterizing collagen self-assembly mechanisms. These findings contribute to the broader understanding of collagen organization in biological and biomaterial contexts, with implications for tissue engineering, fibrosis research, and regenerative medicine. Future work should explore how external factors such as ionic strength and crosslinking agents further modulate collagen fibril formation and its mechanical properties.
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Size effect in plasmonic-enhanced photocatalysis in Au/TiO 2 nanocomposites
Auteur(s): Awada Chawki, Benali Kanoun Mohammed, Ahmed Faheem, Saber Osama, Osama Aya, Osama Mostafa, Jonin C., Brevet Pierre-François
(Article) Publié:
Optical Materials, vol. p. (2025)
Ref HAL: hal-05139815_v1
DOI: 10.1016/j.optmat.2025.117293
Exporter : BibTex | endNote
Résumé: One of the important challenges encountered in photocatalysis applications is to fabricate high performance photocatalysts with an easy and low-cost fabrication method and sustaining a slow hole-electron recombination rate. The latter can be achieved by promoting the synergetic effect between noble metals and metal oxides such as titanium oxide (TiO 2 ) . In this work, gold nanostars/TiO 2 (GNS/TiO 2 ) nanocomposites were prepared using the impregnation method. A study of the dependence of the size on the synergetic effect of GNS/TiO 2 nanocomposites was investigated using TiO 2 nanoparticles with an average size of 5 nm and 20 nm, respectively. The structural, morphological, elemental and optical properties of GNS/TiO 2 nanocomposites were studied by X-ray diffraction (XRD), High-resolution transmission electron microcopy (HRTEM), Energy dispersion X-ray (EDX), selected area electron diffraction (SAED), Raman spectroscopy, adsorption/desorption isotherm, and UV-Vis optical spectroscopy techniques. The photocurrent study was performed with different films of GNS/TiO 2 nanocomposites indicating the importance of the size to enhance photocurrents with the presence of GNS. The photocatalytic activity of the prepared nanocomposites was studied toward the photodegradation of the Naphthol Green B complex dye. 5 nm and 20 nm pure anatase TiO 2 exhibited a very fast degradation of the dye during 19 and 70 minutes with kinetics reaction rate of 0.078 and 0.03 min -1 respectively. By adding GNS, 5 nm and 20 nm GNS/TiO 2 showed shorter photodegradation time of 10 and 15 minutes with kinetics reaction rate of 0.241 and 0.155 min -1 respectively. The latter confirms the strong synergetic effect between GNS and 5nm TiO 2 that may come from its smaller size compared to the 20 nm TiO 2 nanocomposite system. The first principal calculations were performed to study the stability and electronic structures of the Au/TiO 2 composite interface. The interfacial charge properties and the potential drop between the gold and TiO 2 were also studied. The adsorption energies of the Naphthol Green B on the Au/TiO 2 composite interface were also examined.
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