Cell morphology as a design parameter in the bioengineering of cell-biomaterial surface interactions

Control of cell–surface interaction is necessary for biomaterial applications such as cell sheets, intelligent cell culture surfaces, or functional coatings. In this paper, we propose the emergent property of cell morphology as a design parameter in the bioengineering of cell–biomaterial surface interactions. Cell morphology measured through various parameters can indicate ideal candidates for these various applications thus reducing the time taken for the screening and development process. The hypothesis of this study is that there is an optimal cell morphology range for enhanced cell proliferation and migration on the surface of biomaterials. To test the hypothesis, primary porcine dermal fibroblasts (PDF, 3 biological replicates) were cultured on ten different surfaces comprising components of the natural extracellular matrix of tissues. Results suggested an optimal morphology with a cell aspect ratio (CAR) between 0.2 and 0.4 for both increased cell proliferation and migration. If the CAR was below 0.2 (very elongated cell), cell proliferation was increased whilst migration was reduced. A CAR of 0.4+ (rounded cell) favoured cell migration over proliferation. The screening process, when it comes to biomaterials is a long, repetitive, arduous but necessary event. This study highlights the beneficial use of testing the cell morphology on prospective prototypes, eliminating those that do not support an optimal cell shape. We believe that the research presented in this paper is important as we can help address this screening inefficiency through the use of the emergent property of cell morphology. Future work involves automating CAR quantification for high throughput screening of prototypes

Comments On The Proposed Conservation Of Hydrobia Hartmann, 1821 Acuta With A Neotype; Proposed Designation Of Turbo Ventrosus Montagu, 1803 As The Type Species Of Ventrosia Radoman, 1977; And Proposed Emendation Of Spelling Of Hydrobiina Mulsant, 1844 (Insecta, Coleoptera) To Hydrobiusina, So Removing The Homonymy With Hydrobiidae Troschel, 1857 (Mollusca)

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Novel Adhesin from Pasteurella multocida That Binds to the Integrin-Binding Fibronectin FnIII9-10 Repeats▿

Phage display screening with fragmented genomic DNA from the animal pathogen Pasteurella multocida has identified a gene encoding a putative fibronectin binding protein (19). Homologues of this gene (PM1665) are found in all other sequenced members of the Pasteurellaceae. Gene PM1665 has been cloned, and the protein has been expressed. Recombinant PM1665 protein binds to both soluble and immobilized fibronectin and is unique in that it interacts with the integrin-binding fibronectin type III (FnIII) repeats FnIII9-10 and not, as is the case for almost all other fibronectin adhesins, to the N-terminal type I repeats. Surface plasmon resonance analysis revealed a complex binding mechanism with a KD (equilibrium dissociation constant) of 150 nM ± 70 nM. Bioinformatics analysis suggests that the PM1665 protein contains two helix-hairpin-helix (HhH) motifs, and truncation mutation studies have identified the binding site in the protein as a combination of these two HhH motifs in conjunction with a conserved amino acid motif, VNINTA. We have shown that the PM1665 protein is on the cell surface and that binding of P. multocida to fibronectin is almost completely inhibited by anti-PM1665 antiserum. These results support the hypothesis that the PM1665 protein is a member of a new family of fibronectin binding adhesins that are important in the adhesion of P. multocida to fibronectin

Titanium phosphate glass microspheres for bone tissue engineering

We have demonstrated the successful production of titanium phosphate glass microspheres in the size range of ∼10–200 μm using an inexpensive, efficient, easily scalable process and assessed their use in bone tissue engineering applications. Glasses of the following compositions were prepared by melt-quench techniques: 0.5P2O5–0.4CaO–(0.1 − x)Na2O–xTiO2, where x = 0.03, 0.05 and 0.07 mol fraction (denoted as Ti3, Ti5 and Ti7 respectively). Several characterization studies such as differential thermal analysis, degradation (performed using a novel time lapse imaging technique) and pH and ion release measurements revealed significant densification of the glass structure with increased incorporation of TiO2 in the glass from 3 to 5 mol.%, although further TiO2 incorporation up to 7 mol.% did not affect the glass structure to the same extent. Cell culture studies performed using MG63 cells over a 7-day period clearly showed the ability of the microspheres to provide a stable surface for cell attachment, growth and proliferation. Taken together, the results confirm that 5 mol.% TiO2 glass microspheres, on account of their relative ease of preparation and favourable biocompatibility, are worthy candidates for use as substrate materials in bone tissue engineering applications