Degradable emulsion-templated scaffolds for tissue engineering from thiol–ene photopolymerisation

Abstract

Further information on publisher's website:http://dx.doi.org/10.1039/c2sm26250aPublisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractEmulsion templating has been used to prepare highly porous polyHIPE materials by thiol-ene photoinitiated network formation. Commercially available multifunctional thiols and acrylates were formulated into water-in-oil high internal phase emulsions (HIPEs) using an appropriate surfactant, and the HIPEs were photo-cured. The temperature of the HIPE aqueous phase was found to influence the morphology of the resulting materials. In agreement with previous work, a higher aqueous phase temperature (80 o C) gave rise to a larger mean void and interconnect diameter. The influence of temperature on morphology was found to be reduced at higher porosity, but still significant. The Young's modulus of the porous materials was shown to be related to the functionality of the acrylate comonomer used. A mixture of penta-and hexa-acrylate gave rise to a 100-fold increase in modulus, compared to an analogous tri-functional acrylate. The materials could be functionalised conveniently by addition of mono-acrylates or thiols to the organic phase of the precursor HIPE. Degradation was observed to occur at a rate depending on the degradation conditions. Under cell culture conditions at 37 o C, 19% mass loss occurred over 15 weeks. The scaffolds were found to be capable of supporting the growth of keratinocytic cells (HaCaTs) over 11 days in culture. Some penetrative in-growth of the cells into the scaffold was observed.3

Fully biodegradable and biocompatible emulsion templated polymer scaffolds by thiol-acrylate polymerization of polycaprolactone macromonomers

“…The distribution of void diameters was wide in all cases, but within the range which has previously been used for cell culture. In common with earlier work we observe that heating the droplet phase (40 o C) increases both the average void size and distribution 16,22 ( Table 1, figure 4). Cell culture experiments with L929 cells showed that cells readily penetrated into and migrated through the structure as would be required for 3D cell growth ( Figure 5, 6).…”

“…Hexa--Acrylate and Triacrylate PolyHIPE Preparation. For comparison two biodegradable polyHIPEs reported by Caldwell et al based on a hexa--functional acrylate (DPEHA) and a second on a trifunctional acrylate (TMPTA) were also produced according to the previously published procedure 16 . The nominal porosity in each case was 85%.…”

“…Although the thermal curing of thiol--ene polyHIPE materials has also been described 20 , the rapid cure times associated with photocuring offers a distinct advantage as it allows polyHIPE materials to be obtained from monomers which produce highly unstable emulsions, such as multifunctional thiols. Such materials can be produced with nominal porosities up to 90% and are inherently biodegradable due to their aliphatic ester crosslinks 16 . Evaluation of these materials as scaffolds for tissue engineering has shown promise as the materials are capable of supporting the growth of keratinocytes over a culture period of 11 days 16 .…”

“…Such materials can be produced with nominal porosities up to 90% and are inherently biodegradable due to their aliphatic ester crosslinks 16 . Evaluation of these materials as scaffolds for tissue engineering has shown promise as the materials are capable of supporting the growth of keratinocytes over a culture period of 11 days 16 . Partially degradable styrene--based polyHIPE polymers have previously been prepared via thermally initiated free radical polymerization with up to 50 wt% of the total organic phase replaced by PCL--diacrylate macromonomers 18,21 .…”

Osteosarcoma growth on trabecular bone mimicking structures manufactured via laser direct write

“…A study by Pierre et al employed EHA and IBOA monomers with trimethylolpropane triacrylate (TMPTA) crosslinker and Span 80 as surfactant, showing the effect of the monomer choice (EHA or IBOA) on the elastic properties of the monolith as well as employing photoinitiated polymerisation as a curing method [10] . Photoinitiated polymerisation reduces the cure time to seconds, which means that less stable emulsions can be cured which might otherwise destabilise during the long process of thermal curing or with increase in temperature [2,4,10,12] . This approach has potentially increased the versatility of PolyHIPE systems, and there is a growing interest in the use of photocurable monomers for their production [4,8,[11][12][13][14][15][16] .…”