Long term expansion profile of mesenchymal stromal cells at protein nanosheet-stabilised bioemulsions for next generation cell culture microcarriers.

Tremendous progress in the identification, isolation and expansion of stem cells has allowed their application in regenerative medicine and tissue engineering, and their use as advanced in vitro models. As a result, stem cell manufacturing increasingly requires scale up, parallelisation and automation. However, solid substrates currently used for the culture of adherent cells are poorly adapted for such applications, owing to their difficult processing from cell products, relatively high costs and their typical reliance on difficult to recycle plastics and microplastics. In this work, we show that bioemulsions formed of microdroplets stabilised by protein nanosheets displaying strong interfacial mechanics are well-suited for the scale up of adherent stem cells such as mesenchymal stromal cells (MSCs). We demonstrate that, over multiple passages (up to passage 10), MSCs retain comparable phenotypes when cultured on such bioemulsions, solid microcarriers (Synthemax II) and classic 2D tissue culture polystyrene. Phenotyping (cell proliferation, morphometry, flow cytometry and differentiation assays) of MSCs cultured for multiple passages on these systems indicate that, although stemness is lost at late passages when cultured on these different substrates, stem cell phenotypes remained comparable between different culture conditions, at any given passage. Hence our study validates the use of bioemulsions for the long term expansion of adherent stem cells and paves the way to the design of novel 3D bioreactors based on microdroplet microcarriers

Ordered arrays of magnetic nanowires investigated by polarized small-angle neutron scattering

Polarized small-angle neutron scattering (PSANS) experimental results obtained on arrays of ferromagnetic Co nanowires ($\phi\approx13$ nm) embedded in self-organized alumina (Al$_{2}$O$_{3}$) porous matrices are reported. The triangular array of aligned nanowires is investigated as a function of the external magnetic field with a view to determine experimentally the real space magnetization $\vec{M}(\vec{r})$ distribution inside the material during the magnetic hysteresis cycle. The observation of field-dependentSANSintensities allows us to characterize the influence of magnetostatic fields. The PSANS experimental data are compared to magnetostatic simulations. These results evidence that PSANS is a technique able to address real-space magnetization distributions in nanostructured magnetic systems. We show that beyond structural information (shape of the objects, two-dimensional organization) already accessible with nonpolarized SANS, using polarized neutrons as the incident beam provides information on the magnetic form factor and stray fields \textgreek{m}0Hd distribution in between nanowires.Comment: 13 pages, 10 figures, submitted to Phys. Rev.

Directing cell migration using micropatterned and dynamically adhesive polymer brushes

This work was funded by the BBSRC, New Investigator Award (BB/J000914/1)

Physico-chemical characterization of Antheraea mylitta silk mats for wound healing applications.

In the field of plastic reconstructive surgery, development of new innovative matrices for skin repair is in demand. The ideal biomaterial should promote attachment, proliferation and growth of cells. Additionally, it should degrade in an appropriate time period without releasing harmful substances, not exerting a pathological immune response. The materials used should display optimized mechanical properties to sustain cell growth and limit scaffold contraction. Wound healing is a biological process directed towards restoration of tissue that has suffered an injury. An important phase of wound healing is the generation of a basal epithelium wholly replacing the epidermis of the wound. Wild silk from Antheraea mylitta meets these demands to a large extent. To evaluate the effects of the treatment, Antheraea mylitta and Bombyx mori samples were characterized by SEM-EDX, FT-IR, XRD and TGA-DSC techniques. Preliminary cell growth behavior was carried out by culturing epidermal cells and proliferation was quantified via viability assay. Moreover, Antheraea mylitta possesses excellent cell-adhesive capability, effectively promoting cell attachment and proliferation. Antheraea mylitta serves as a delivery vehicle for cells. With all these unique features, it is expected that Antheraea mylitta mat will have wide utility in the areas of tissue engineering and regenerative medicine.Prof. Shyamkumar Vootla and Dr. Julien Gautrot thanks to Department of Science and Technology (DST), New Delhi. India and United Kingdom India Education and Research Initiative (UKIERI), British Council, United Kingdom, for funding of this project (DST/INT/UK/P-52). Tis work was supported by Commonwealth Academic Fellowship awarded to Prof. Shyamkumar Vootla by the Commonwealth Association of Universities, United Kingdom

Highly Stable RNA Capture by Dense Cationic Polymer Brushes for the Design of Cytocompatible, Serum-Stable SiRNA Delivery Vectors

The high density of polymer brushes confers to these coatings unique physicochemical properties, in particular for the regulation of biomolecular interaction and the design of highly selective coatings for biosensors and protein patterning. Here, we show that high density poly­(dimethylaminoethyl methacrylate) cationic polymer brushes enable the stable uptake of high levels of oligonucleotides. This is proposed to result from the high degree of crowding and associated increase in entropic driving force for the binding of polyelectrolytes such as nucleic acid molecules. We further demonstrate the ease with which such coatings allow the design of highly structured nanomaterials for siRNA delivery using block copolymer-brush-based nanoparticles that allow the protection of oligonucleotides by a protein-resistant outer block. In particular, these nanomaterials display a high serum stability and low cytotoxicity while retaining excellent knock down efficiencies. Polymer brush-based nanomaterials therefore appear particularly attractive for the rational design of a new generation of high performance theranostics and RNA delivery probes