Noteworthy: Silk Scaffolds

BBC: Silkworms Could Aid Breakthrough in Tissue Engineering

Every Monday I plan to talk about something in the news and how this relates to the field of tissue engineering. This week I’ve posted a link to a video about the creation of silk. Textile specialists have long looked at silk because it is a naturally produced material, from either spiders or silk worms. However, the first review of the scientific use of silk as a biomaterial wasn’t published until 2003. This is yet another example of just how rapidly the field of tissue engineering is progressing and how rapidly it is growing. In 2003, just 189 papers were published, according to the scientific publishing database PubMed, compared to 438 in 2011.
Today, it’s very evident that silk scaffolds are being tested around the world, from the USA, to Germany, to China, to Australia, and everywhere in between. Silk is, however, very rarely used on its own, and when it is, it does need to be chemically treated to change its mechanical, and sometimes biological, properties. Silk from various spiders, for example, has to be processed to remove an outer coating which is biologically toxic. Much more common is to find silk that has been modified, either by adding adenovirus to stimulate a biological process, or through the attachment of various proteins etc. that will give it various properties. Crosslinking of fibers strengthens the network and allows it to hold its shape better. And very commonly silk will be mixed with synthetic polymers such as polyacrylamide, whose biological properties are much easier to control to get reproducible results.
What the group did at the Institute of Materials Research and Engineering in Singapore accomplished in making colored silk worms that can generate fluorescently colored silk is very interesting because, as stated in the video, it makes it easier to do fluorescence imaging of the scaffold. From a biological standpoint it is interesting not just because of the new product it produces, but because it raises the possibility of incorporating many different characteristics into the silk, such as mechanical properties, or modified biological moieties (both would come from modifying the structure of the silk fibroin molecules during production by the silkworm). Previously, all materials had to be modified post-extraction and purification, now they can be modified before production even starts. It’s the biological equivalent of producing spinach-flavored pasta instead of taking plain pasta, cooking it, and adding spinach.


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