Monday, 17 February 2014

Nanostructured Nonwovens with Self-Assembling Peptides

More from the EDANA NIA 2013 Conference in Roubaix...

Robabeh Gharaei of Leeds University (UK) said the materials of the title were being developed as nonwoven scaffolds for tissue engineering.  Such scaffolds had to be highly porous 3D structures which were biocompatible, bioresorbable, biodegradable and had an appropriate surface chemistry.  Examples given included naturally derived polymers such as collagen, chitosan, and elastin or synthetic polymers such as polycaprolactone, polylactic acid or  polyglycolic acid and its copolymers.  These could be 3D printed into the appropriate porous structure, spun into nanofibres, or even simply used as a hydrogel.  Improvements promoting cell attachment, cell proliferation, cell differentiation and extracellular formation were required, and the incorporation of self-assembling peptides within the polymer was thought to be a potential solution.

Electrospun nonwovens have therefore been made from 6% PCL in hexafluoro-2-propanol loaded with the peptides P11-4 and P11-8, both of which were bioactive and specially synthesised for use in nonwoven scaffolds.  Concentrations of 20 and 40g/l of the peptides in the dope were used and both caused the production of a biphasic structure (a mixture of filaments and short submicron fibres).  ATR-FTIR analysis of the fibres showed the presence of both monomeric and beta-sheet peptide structures. It was postulated that the peptides were self-assembling into “beta-sheet tapes” during spinning and causing this mixture. 

Asked if the biofunctionality of these nonwovens had been checked, Ms Gharaei said they hadn’t but she expected to see improvements over the current scaffolds.  The peptides did not self-assemble in solution so it must be happening during spinning.  Maybe the peptide is affecting the surface tension of the dope and thereby affecting the resulting fibres.

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