2, Division of Surgery and Interventional Science, Centre for Nanoscience and Technology, London, , United Kingdom
Several diseases include cancer, skin diseases, inflammatory conditions, trauma and congenital deformalities cause ear and nose defects that require reconstuction. Due to the wide patient population that this affects, nose reconstruction creates a huge social and economic burden. Each year, 1/6000 children are born with a small or missing ear, a condition called microtia. This devastating facial disfigurement causes high physical, social and mental burden for both the child and parent. Current surgical reconstruction involves harvesting tissue from elsewhere in the body, to recreate the cartilage framework of the ear and the nose and then implanting the framework beneath the skin. These techniques cause pain, are limited by tissue availability, can fail and have potential wound-healing complications.
Several synthetic and biological materials have been considered for the reconstruction of the nose and ear but with high levels of infection, unnatural look and feel, they are not considered an acceptable alternative. Synthetic materials are promising candidates to provide the mechanicalproperties and support for the constructs. However, biological materials are useful as they have good biocompatibility and can support tissue formation, which synthetic materials often lack. The incorporation of patient's own cells within the construct can also enhance the biocompatibility of the implant material.
Additive three dimensional bio plotting, a modified form of Fused Deposition Modelling (FDM) has now allowed synthetic and biological biomaterials to be combined to create organ replacements. In addition, to being able to create more complex shapes which better mimic the native tissue, they can be manufactured specific to the patient. Bioplotting also allows the direct printing of cells with the material to create a biocompatible and functional implant.
The work described in this paper represents a new approach to ear and nose reconstruction using 3D-Bio-plotting. We have tested several combinations of biological hydrogels and synthetic polysaccharide composite materials to act as the replacement for the cartilage framework of the ear and the nose.
We describe the concepts being developed from 3D to 4D biofabrication using a high precision Bioplotter robot (Envisiontec) to ensure we are creating accurate patient focused auricular and nasal relacements. The bioplotter has proven capable of printing several materials sequentially in very precise locations with and without cells incorporated in the material. Now, in the second stage of our current programme, we are exploring suitable combinations of synthetic and biological material for nose and ear reconstruction, printing of the patient's own cells within the biological component of the material will be optimised. The ability of the cells to survive, grow and support tissue formation is driven by novel laminar( low shear) flow mixing to ensure maximum stem cell survival.