Highly porous polymeric materials are prepared by thiol–ene and thiol–yne mediated network formation using high internal phase emulsion templates. The efficiency of network formation is between 80 and 90% for all materials while the thiol–yne materials display enhanced strength and toughness due to their higher degree of crosslinking.

Glycidyl methacrylate (GMA) emulsion-templated porous polymers (polyHIPEs) were prepared by thermal and photopolymerisation and derivatised with morpholine, tris(2-aminoethylamine) and a bisamino-PEG homobifunctional molecule. The extent of the functionalization reactions was investigated by a range of qualitative and quantitative techniques (FTIR, CHN analysis, titration, XPS, HR-MAS NMR spectroscopy, ninhydrin assay and Fmoc number determination) and was found to be excellent for small molecule amines (up to 89% conversion) but low for the reaction with PEG (2% conversion). This was ascribed to the high exclusion volume of the PEG chains in solution. Proteinase K (Pro K) was subsequently immobilized covalently onto the GMA polyHIPE material, both directly via reaction with surface epoxy groups and indirectly by activation of the pendent amine groups of PEGylated polyHIPE with glutaraldehyde then reductive amination with the enzyme. The activity of the supported enzymes was determined by a continuous electrochemical assay involving the hydrolysis of N-acetyl-l-tyrosine ethyl ester. The directly immobilized Pro K was found to have an activity of only 3.6 U/g whereas the activity of the enzyme immobilized via the PEG linker was much higher (up to 78 U/g)

Printing of novel linear polypeptide hydrogel bioinks and stabilisation of structures by post-printing UV-triggered crosslinking through catalyst free thiol–yne click chemistry of cysteine and propiolated 4-arm PEG.

Electrospinning is considered a relatively simple and versatile technique to form high porosity porous scaffolds with micron to nanoscale fibers for biomedical applications. Here, electrospinning of unsaturated aliphatic polyglobalide (PGl) into well-defined fibers with an average diameter of 9 μm is demonstrated. Addition of a dithiol cross-linker and a photoinitiator to the polymer solution enabled the UV-triggered intracross-linking of the fibers during the spinning process. The in situ cross-linking of the fibers resulted in amorphous material able to swell up to 14% in tetrahydrofurane (THF) without losing the fiber morphology. Seeding mesenchymal stem cells (MSCs) onto both cross-linked and non-cross-linked PGl fibers proved their compatibility with MSCs and suitability as scaffolds for cell growth and proliferation of MSCs. Moreover, the ability to directly load cross-linked PGl with hydrophobic molecules by soaking the fiber mesh in solution is shown with Rhodamine B and Indomethacin, a hydrophobic anti-inflammatory drug. This marks an advantage over conventional aliphatic polyesters and opens opportunities for the design of drug loaded polyester scaffolds for biomedical applications or tissue engineering.