66 research outputs found
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
Directing cell migration using micropatterned and dynamically adhesive polymer brushes
This work was funded by the BBSRC, New Investigator Award (BB/J000914/1)
Biofunctionalized Patterned Polymer Brushes via Thiol-Ene Coupling for the Control of Cell Adhesion and the Formation of Cell Arrays
Thiol–ene
radical coupling is increasingly used for the
biofunctionalization of biomaterials. Thiol–ene chemistry presents
interesting features that are particularly attractive for platforms
requiring specific reactions with peptides or proteins and the patterning
of cells, such as reactivity in physiological conditions and photoactivation.
In this work, we synthesized alkene-functionalized (allyl and norbornene
residues) antifouling polymer brushes (based on polyÂ(oligoethylene
glycol methacrylate)) and studied thiol–ene coupling with a
series of thiols including cell adhesive peptides RGD and REDV. The
adhesion of umbilical
vein endothelial cells (HUVECs) to these interfaces was studied and
highlighted the absence of specific integrin engagement to REDV, in
contrast to the high level of cell spreading observed on RGD-functionalized
polymer brushes. This revealed that α<sub>4</sub>β<sub>1</sub> integrins (binding to REDV sequences) are not sufficient
on their own to sustain HUVEC spreading, in contrast to α<sub>v</sub>β<sub>3</sub> and α<sub>5</sub>β<sub>1</sub> integrins. In addition, we photopatterned peptides at the surface
of polyÂ(oligoethylene glycol methacrylate) (POEGMA) brushes and characterized
the quality of the resulting arrays by epifluorescence microscopy
and atomic force microscopy (AFM). This allowed the formation of cell
patterns and demonstrated the potential of thiol–ene based
photopatterning for the design of cell microarrays
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 polyÂ(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
- …