Skip to 0 minutes and 13 secondsMy background is a clinical dermatologist. So I studied the biology and science of the skin, and then applied it to clinical work with all sorts of diseases of the skin, ranging from cancers through to inflammatory skin problems, and ulcers, and to light wound healing. So I think 3D printing immediately offers the opportunity to help us with abnormal wound healing, delayed would healing, and pathogenic ulcers. The other areas where 3D printing might play a big role would be in disorders where the integrity of the skin's disrupted. And we see a lot of skin disorders where, for one reason or another, the integrity of the skin is lost.
Skip to 0 minutes and 59 secondsAnd I think 3D printing and 3D printing technology, biofabrication, is going to give us the opportunity to help these patients. I think the ability to arrange cells into compartments-- and the skin is a very compartmentalised organ with the dermis and epidermis-- really, some great opportunity there to stratify the skin and recreate the natural, or try to replicate what are these natural layers in a biofabricated skin. The skin, of course, is a very important immunologic organ. Where you've got the epidermis, which is generally a fraction of a millimetre. You've got the dermis, which can be up to one to two millimetres depending on which part of the body you're talking about.
Skip to 1 minute and 40 secondsSo it's a pretty thin tissue, and a very, very intricate arrangement in terms of layers and organisation within the layers. The ability to customise and individualise biofabricated skin to the person's needs, incorporate perhaps their cells within the structure, will be very important. A lot of the issues to do with using grafts, particularly xenografts and donated skin, of course, is immune rejection. And this would really be a great advance in being able to get around that. So we have gained some insights into the complexity of the structure of skin. We see there is a need for 3D printing to be able to produce layers of cells if we are to facilitate skin regeneration to assist in wound healing.
Skip to 2 minutes and 31 secondsSo we have some real challenges in the ability to print multiple cells and to create those very sophisticated structures. So, Steve, will 3D printing be able to deliver that ability, the ability to create layers of cells that might facilitate skin regeneration? Well, inkjet printing as an alternative to extrusion-based printing does give us the layer resolution that we'll need. We've been working in this area for the last five years, tailoring inks to specific cell types, to allow us to put down multiple different materials simultaneously, taking cues from PolyJet type technologies where we can discretely distribute cells within two-dimensional slices, and then reposition additional cells close by. So we've got accuracy of nearly single cell per droplet.
Skip to 3 minutes and 18 secondsUsing inkjet printing, we can print living cells with extremely high resolution, even one cell at a time. Achieving cell printing requires some clever bio-ink formulations. If normal cell culture medium is used as the ink, the living cells can burst due to the high stresses of the jetting process. But when biopolymers are added, the cells can be protected and printed successfully. Printing of living cells can allow for development of novel wound healing strategies.
Skip to 3 minutes and 54 secondsLiving cells derived from the patient could be deposited at the site of injury.
Skip to 4 minutes and 3 secondsDifferent types of cells could be built up in sequential layers.
Skip to 4 minutes and 11 secondsSuch a strategy could accelerate healing or reduce trauma after surgery.
Skip to 4 minutes and 24 secondsAnd the creation of these inks has required the identification of materials with quite unique properties. These materials are what we call shear thinning materials, naturally occurring organic molecules which will facilitate the suspension of living cells in the bio-ink, which will shear thin during the printing process in order to protect the cell, and then will reformulate on the other side of the printing process to create the 3D structures. This discovery of these properties in naturally occurring materials has taken us a step closer to being able to create very sophisticated layers of cells mimicking the properties of skin.
As you heard in the video, inkjet printing, as an alternative to extrusion–based printing, does give the layer resolution needed for skin regeneration.
With ink jet printing, very low volume droplets can be put down onto the surface droplets with a volume of ten to twenty picolitres to get very high detailed resolution. The challenge here however, is the material itself. To operate on an ink jet printer the material has to fall within a very tight window of viscosity and surface tension. This is quite different to extrusion printing which works with solid based materials or hot melt polymers.
© University of Wollongong, 3D Bioprinting: Printing parts for bodies, 2014, Wallace, G.G., Cornock, R.C., O’Connell, C.D., Beirne, S., Dodds, S., Gilbert, F.