Cell-derived nanovesicles from mesenchymal stem cells as extracellular vesicle-mimetics in wound healing

Wound healing is a dynamic process that involves a series of molecular and cellular events aimed at replacing devitalized and missing cellular components and/or tissue layers. Recently, extracellular vesicles (EVs), naturally cell-secreted lipid membrane-bound vesicles laden with biological cargos including proteins, lipids, and nucleic acids, have drawn wide attention due to their ability to promote wound healing and tissue regeneration. However, current exploitation of EVs as therapeutic agents is limited by their low isolation yields and tedious isolation processes. To circumvent these challenges, bioinspired cell-derived nanovesicles (CDNs) that mimic EVs were obtained by shearing mesenchymal stem cells (MSCs) through membranes with different pore sizes. Physical characterisations and high-throughput proteomics confirmed that MSC-CDNs mimicked MSC-EVs. Moreover, these MSC-CDNs were efficiently uptaken by human dermal fibroblasts and demonstrated a dose-dependent activation of MAPK signalling pathway, resulting in enhancement of cell proliferation, cell migration, secretion of growth factors and extracellular matrix proteins, which all promoted tissue regeneration. Of note, MSC-CDNs enhanced angiogenesis in human dermal microvascular endothelial cells in a 3D PEG-fibrin scaffold and animal model, accelerating wound healing in vitro and in vivo. These findings suggest that MSC-CDNs could replace both whole cells and EVs in promoting wound healing and tissue regeneration.

Biomineralization of lithium nanoparticles by Li-resistant Pseudomonas rodhesiae isolated from the Atacama salt flat

BACKGROUND: The Atacama salt flat is located in northern Chile, at 2300 m above sea level, and has a high concentration of lithium, being one of the main extraction sites in the world. The effect of lithium on microorganism communities inhabiting environments with high concentrations of this metal has been scarcely studied. A few works have studied the microorganisms present in lithium-rich salt flats (Uyuni and Hombre Muerto in Bolivia and Argentina, respectively). Nanocrystals formation through biological mineralization has been described as an alternative for microorganisms living in metal-rich environments to cope with metal ions. However, bacterial lithium biomineralization of lithium nanostructures has not been published to date. In the present work, we studied lithium-rich soils of the Atacama salt flat and reported for the first time the biological synthesis of Li nanoparticles. RESULTS: Bacterial communities were evaluated and a high abundance of Cellulomonas, Arcticibacter, Mucilaginibacter, and Pseudomonas were determined. Three lithium resistant strains corresponding to Pseudomonas rodhesiae, Planomicrobium koreense, and Pseudomonas sp. were isolated (MIC > 700 mM). High levels of S2− were detected in the headspace of P. rodhesiae and Pseudomonas sp. cultures exposed to cysteine. Accordingly, biomineralization of lithium sulfide-containing nanomaterials was determined in P. rodhesiae exposed to lithium salts and cysteine. Transmission electron microscopy (TEM) analysis of ultrathin sections of P. rodhesiae cells biomineralizing lithium revealed the presence of nanometric materials. Lithium sulfide-containing nanomaterials were purified, and their size and shape determined by dynamic light scattering and TEM. Spherical nanoparticles with an average size < 40 nm and a hydro-dynamic size ~ 44.62 nm were determined. CONCLUSIONS: We characterized the bacterial communities inhabiting Li-rich extreme environments and reported for the first time the biomineralization of Li-containing nanomaterials by Li-resistant bacteria. The biosynthesis method described in this report could be used to recover lithium from waste batteries and thus provide a solution to the accumulation of batteries.

Bio-Nanotechnology for Active Food Packaging.

The most commonly used packaging material is associated with environmental issues as they are non-degradable in nature. The number of attempts are made for developing the eco-friendly degradable biopolymers as ideal food packaging. The biopolymers developed are not commercialized as they have poor mechanical strength and resistance properties. Thus to enhance the following faults in the reinforcing material are added which resulted in the composites formation. During various food processing operations the nanotechnology approach is employed such as encapsulation of the material in the nanoparticles, which can be delivered to the targeted site, enhancement of the flavor, integration of antibacterial agents with the nanoparticle in the food, enhancement of shelf-life for storage, and contamination sensing. Food packaging substances synthesized by nanotechnology may increase the shelf-life of the food as they provide resistive packaging, increase the level of food safety, liberate the preservatives for enhancing the life of the food and notify the consumer either the food is consumable or spoiled. Nano-supplements are integrated by the encapsulation method for efficient dietary as well as drug delivery systems. Nano-materials are not well evaluated for the health risk and environmental issues associated with it even the side-effects are unexploited. Various authorities are working prompt designing of guidelines and legislation policies for further acceptance of Nano-based materials in food packaging systems. Biologically synthesized nanoparticles will serve as a significant tool to conquer present contests that are linked with food packaging constituents.