We studied oil in water Pickering emulsions stabilized by cellulose nanocrystals obtained by hydrochloric acid hydrolysis of bacterial cellulose. The resulting solid particles, called bacterial cellulose nanocrystals (BCNs), present an elongated shape and low surface charge density, forming a colloidal suspension in water. The BCNs produced proved to stabilize the hexadecane/water interface, promoting monodispersed oil in water droplets around 4 μm in diameter stable for several months. We characterized the emulsion and visualized the particles at the surface of the droplets by scanning electron microscopy (SEM) and calculated the droplet coverage by varying the BCN concentration in the aqueous phase. A 60% coverage limit has been defined, above which very stable, deformable droplets are obtained. The high stability of the more covered droplets was attributed to the particle irreversible adsorption associated with the formation of a 2D network. Due to the sustainability and low environmental impact of cellulose, the BCN based emulsions open opportunities for the development of environmentally friendly new materials.

International audienceCellulosic colloidal nanorods of different origins were used in order to investigate the effect of various elongated shapes adsorbed at the oil-water interface for Pickering emulsion characteristics. Nanocrystals of length ranging from 185 nm to 4 μm were obtained from the hydrolysis of cellulose microfibrils of three different biological origins: cotton (CCN), bacterial cellulose (BCN) and Cladophora (ClaCN) leading to aspect ratios ranging from 13 to 160. These nanocrystals are irreversibly adsorbed at the oil-water interface and form ultrastable emulsions. Individual droplets of similar diameter were obtained under diluted conditions, illustrating both similar wetting properties and nanocrystal flexibility for the three different types of nanocrystals. However, it was shown that the aspect ratio directly influences the coverage ratio giving rise, on the one hand to a dense organisation (coverage >80%) with short nanocrystals and on the other hand to an interconnected network of low covered droplets (40%) when longer nanocrystals are used. An estimation is made showing that for the longer nanocrystals, 55% of the nanocrystals introduced are involved in the network of the material. The capillary force that promotes attractive interactions between nanocrystals was also addressed. These results lead to a better understanding of the adsorption process for rod-like particles of various aspect ratios for the elaboration of a controlled surface architecture, from a homogeneous monolayer to interconnected porous multilayered interfaces

Neutral cellulose nanocrystals dispersed in water were shown in a previous work to stabilize oil/water interfaces and produce Pickering emulsions with outstanding stability, whereas sulfated nanocrystals obtained from cotton did not show interfacial properties. To develop a better understanding of the stabilization mechanism, amphiphilic properties of the nanocrystals were modulated by tuning the surface charge density to investigate emulsifying capability on two sources of cellulose: cotton linters (CCN) and bacterial cellulose (BCN). This charge adjustment made it possible to determine the conditions where a low surface charge density, below 0.03 e/nm(2), remains compatible with emulsification, as well as when assisted by charge screening regardless of the source. This study discusses this ability to stabilize oil-in-water emulsions for cellulose nanocrystals varying in crystalline allomorph, morphology, and hydrolysis processes related to the amphiphilic character of nonhydrophobized cellulose nanocrystal.

Innovative methods for treating impaired and hard-to-heal wounds are needed. Novel strategies are needed for faster healing by reducing infection, moisturizing the wound, stimulating the healing mechanisms, speeding up the wound closure and reducing scar formation. In the past few years, nanotechnology has been constantly revolutionizing the treatment and management of wound care, by offering novel solutions which include but are not limited to: state-of-the-art materials, so called 'smart' biomaterials and theranostic nanoparticles. Nanotechnology-based therapy has recently announced itself as a possible next-generation therapy that is able to advance wound healing to cure chronic wounds. In this communication, the recent progress in advanced therapy for cutaneous wound healing during last 5 years using a nanotechnology-based approach is summarized.

In this study, several formulations of nanoceria and dextran-nanoceria with curcumin, each demonstrated to have anti-cancer properties, were synthesized and applied as treatment for human childhood neuroblastoma. The anti-cancer activities of these formulations were explored in neuroblastoma models of both MYCN-amplified and non-amplified cell lines. Ceria nanoparticles, coated with dextran and loaded with curcumin, were found to induce substantial cell death in neuroblastoma cells (up to a 2-fold and a 1.6-fold decrease in cell viability for MYCN-upregulated and normal expressing cell lines, respectively; *p < 0.05) while producing no or only minor toxicity in healthy cells (no toxicity at 100 μM; **p < 0.01). This formulation evokes prolonged oxidative stress, stabilizing HIF-1α, and inducing caspase-dependent apoptosis (up to a 2.4-fold increase over control; *p < 0.05). Overall, nano-therapeutic treatments showed a more pronounced effect in MYCN-amplified cells, which are traditionally more resistant to drug therapies. These results represent a very promising alternative to small molecule drug therapies for robust cancers.

Rheumatoid arthritis (RA) is an autoimmune disease that affects 1-2% of the human population worldwide, and effective therapies with targeted delivery for local immune suppression have not been described. We address this problem by developing a novel theranostic nanoparticle for RA and assessed its therapeutic and targeting effects under image-guidance. Methods: Albumin-cerium oxide nanoparticles were synthesized by the biomineralization process and further conjugated with near-infrared, indocyanine green (ICG) dye. Enzymatic-like properties and reactive oxygen species (ROS) scavenging activities, as well as the ability to reprogram macrophages, were determined on a monocyte cell line in culture. The therapeutic effect and systemic targeting potential were evaluated in collagen-induced arthritis (CIA) mouse model using optical/optoacoustic tomographic imaging. Results: Small nanotheranostics with narrow size distribution and high colloidal stability were fabricated and displayed high ROS scavenging and enzymatic-like activity, as well as advanced efficacy in a converting pro-inflammatory macrophage phenotype into anti-inflammatory phenotype. When administrated into affected animals, these nanoparticles accumulated in inflamed joints and revealed a therapeutic effect similar to the gold-standard therapy for RA, methotrexate. Conclusions: The inflammation-targeting, inherent contrast and therapeutic activity of this new albumin-cerium oxide nanoparticle may make it a relevant agent for assessing severity in RA, and other inflammatory diseases, and controlling inflammation with image-guidance. The design of these nanotheranostics will enable potential clinical translation as systemic therapy for RA.

The purpose of this study was to prepare dexamethasone-loaded polymeric nanoparticles and evaluate their potential for transport across human placenta. Statistical modeling and factorial design was applied to investigate the influence of process parameters on the following nanoparticle characteristics: particle size, polydispersity index, zeta potential, and drug encapsulation efficiency. Dexamethasone and nanoparticle transport was subsequently investigated using the BeWo b30 cell line, an in vitro model of human placental trophoblast cells, which represent the rate-limiting barrier for maternal-fetal transfer. Encapsulation efficiency and drug transport were determined using a validated high performance liquid chromatography method. Nanoparticle morphology and drug encapsulation were further characterized by cryo-transmission electron microscopy and X-ray diffraction, respectively. Nanoparticles prepared from poly(lactic-co-glycolic acid) were spherical, with particle sizes ranging from 140–298 nm, and encapsulation efficiency ranging from 52–89%. Nanoencapsulation enhanced the apparent permeability of dexamethasone from the maternal compartment to the fetal compartment more than 10-fold in this model. Particle size was shown to be inversely correlated with drug and nanoparticle permeability, as confirmed with fluorescently-labeled nanoparticles. These results highlight the feasibility of designing nanoparticles capable of delivering medication to the fetus, in particular, potential dexamethasone therapy for the prenatal treatment of congenital adrenal hyperplasia.

This research is devoted to the development and optimization of fine purification processes realized on short monolithic columns (CIM disks), using influenza vaccine and viruslike synthetic particles as model objects. The pseudoaffinity mode of liquid chromatography has been used as a tool for dynamic adsorption experiments. Viruslike particles, close to the dimensions of influenza viruses, were developed by means of main antigen of influenza viruses (hemeagglutinin) covalent binding to the outer aminated surface of synthetic latex particles. The natural receptor analogues of sialic acid were used as affinity ligands immobilized on the surface of the CIM disk by different ways to achieve a high adsorption capacity. Also, some other ligands were tested as possible candidates for virus capturing. The affinity binding parameters for influenza A virus were obtained by frontal elution method at optimized chromatographic conditions and immobilization schemes. The experimental data pointed out the possibility of selective isolation of hemeagglutinin from a mixture of vaccine proteins. The results obtained by fast affinity chromatography have shown functional and sterical correspondence viruslike synthetic models to influenza viruses. Additionally, the optimization of chromatographic conditions allowed isolation of influenza virus A while maintaining its virulence. The maximum value of adsorption capacity was registered for a monolithic disk, modified subsequently by chitosan and 2,6-sialyllactose and found to be equal to 6.9 x 10(12) virions/mL support.