Chemical treatment of the intra-canal dentin surface: a new approach to modify dentin hydrophobicity

Objective This study evaluated the hydrophobicity of dentin surfaces that were modified through chemical silanization with octadecyltrichlorosilane (OTS). Material and Methods An in vitro experimental study was performed using 40 human permanent incisors that were divided into the following two groups: non-silanized and silanized. The specimens were pretreated and chemically modified with OTS. After the chemical modification, the dentin hydrophobicity was examined using a water contact angle measurement (WCA). The effectiveness of the modification of hydrophobicity was verified by the fluid permeability test (FPT). Results and Conclusions Statistically significant differences were found in the values of WCA and FPT between the two groups. After silanization, the hydrophobic intraradicular dentin surface exhibited in vitro properties that limit fluid penetration into the sealed root canal. This chemical treatment is a new approach for improving the sealing of the root canal system

The "how" and "where" behind the functionalization of graphene oxide by thiol-ene "click" chemistry

Graphene oxide (GO) is a 2D nanomaterial with unique chemistry due to the combination of sp2 hybridization and oxygen functional groups (OFGs) even in single layer. OFGs play a fundamental role in the chemical functionalization of GO to produce GO-based materials for diverse applications. However, traditional strategies that employ epoxides, alcohols, and carboxylic acids suffer from low control and undesirable side reactions, including by-product formation and GO reduction. Thiol-ene “click” reaction offers a promising and versatile chemical approach for the alkene functionalization (−C=C−) of GO, providing orthogonality, stereoselectivity, regioselectivity, and high yields while reducing by-products. This review examines the chemical functionalization of GO via thiol-ene “click” reactions, providing insights into the underlying reaction mechanisms, including the role of radical or base catalysts in triggering the reaction. We discuss the “how” and “where” the reaction takes place on GO, the strategies to avoid unwanted side reactions, such as GO reduction and by-product formation. We anticipate that multi-functionalization of GO via the alkene groups will enhance GO physicochemical properties while preserving its intrinsic chemistry

Targeted Gold Nanorods for Cancer Imaging and Therapy

Les nanobâtonnets d'or (GNRs) sont d'excellents candidats pour l'imagerie, le diagnostic et le traitement du cancer en raison de leurs propriétés chimiques, optiques et biologiques. Nous avons étudié les conditions de synthèse afin d obtenir des GNRs purs fonctionnalisés avec des polyéthylènes glycols (PEG). Nous avons établi les conditions optimales pour la préparation et la functionallisation des GNRs purs utilisables pour les applications biologiques. Afin d assurer la reconnaissance spécifique de tumeurs, nous avons ensuite lié des ligands/récepteurs permettant le ciblage tumorale comme le peptide RGD ou des protéines comme la toxine de Shiga sur la surface des GNRs. L excellent viabilité des cellules et l importante capture spécifique par les cellules de ces GNR-peptides / protéines démontrent l'avantage de l utilisation de ces constructions par rapport à une stratégie non spécifique. Nous avons examiné l efficacité de cette stratégie en termes d'imagerie photo-acoustique et de la thérapie photothermique. Nous étions particulièrement intéressés par une destruction quantitative et ciblée des cellules vivantes via une thérapie photothermique utilisant les GNRs. Nous résultats montrent qu une destruction des systèmes biologiques est possible uniquement lorsqu un contact direct existe entre la cellule et les GNRs, obtenu dans le cas de ciblage actif. Ensuite, nous avons testé les GNRs ciblées in vivo dans un modèle murin de xénogreffe. Nous avons particulièrement étudié la biodistribution des GNRs dans l animal et leur accumulation/rétention au niveau des tumeurs. Enfin, nous avons utilisé la thérapie photothermique sur les sites tumoraux ciblés les GNRsGold nanorods (GNR) are excellent candidates for cancer imaging, diagnosis and therapy due to their unique chemical, optical and biological properties. We have investigated the conditions for the synthesis of ultrapure GNR functionalized with polyethylene glycols (PEG) suitable for biological applications. Several factors such as PEG chain length, reaction conditions and purification method greatly influence the size, optical properties and long-term stability of GNR. To push our system toward specific tumor recognition we then linked tumor targeting moieties like the peptide RGD or the protein Shiga toxin B onto the surface of GNR. Excellent cell viability and specific cellular uptake of these peptide/protein coated ultrapure GNR proofed the advantage of these constructs over an untargeted strategy. We further examined the effectiveness and efficiency of our approach in terms of photoacoustic imaging and photothermal therapy. We were especially interested in a quantitative and targeted destruction of living cells by gold nanorod guided photothermal therapy. Our novel findings show evidence that efficient treatment of biological systems is only possible when a direct, active targeting by the GNR is achieved. Further on we tested our nanodevices in tumor xenograft mice. Herein we monitored the biodistribution of the GNR in living mice as well as their surface specific uptake into malignant tissue. Last but not least in a first trial we generated a lethal heat increase at the GNR targeted tumor sitesPARIS-BIUSJ-Biologie recherche (751052107) / SudocSudocFranceF

Preparation of bactericidal cationic PDMS surfaces using a facile and efficient approach

International audienc

The Paradoxical Thermodynamic Basis for the Interaction of Ethylene Glycol, Glycine, and Sarcosine Chains with Bovine Carbonic Anhydrase II: An Unexpected Manifestation of Enthalpy/Entropy Compensation

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Dependence of Effective Molarity on Linker Length for an Intramolecular Protein−Ligand System

International audienc

Biomimetic engineering of non-adhesive glycocalyx-like PDMS surfaces

International audienc