Bio-Inks for High Resolution 3D Inkjet Printing of Vasculature

Apr10Wed

Bio-Inks for High Resolution 3D Inkjet Printing of Vasculature

Wed, 10/04/2019 - 13:30 to 14:30

Location:

Speaker: 
Brian Derby
Affiliation: 
University of Manchester
Synopsis: 

Inkjet printing is a versatile tool used in additive manufacturing/3D printing with the benefit of multi-material deposition of picolitre volumes of material. A number of previous studies have demonstrated the utility of inkjet printing in producing vascularized structures and depositing cells for applications in tissue engineering and regenerative medicine. Despite the small droplet size delivered by inkjet printing (a 1 pL drop has a diameter of approximately 12.5 m), state-of-the-art bioprinted structures have minimum features in the range 100 – 200 m and have shown little improvement in resolution over the last 10 years. In order to print vascularised structures to allow transport of oxygen and nutrients to prototissues in culture, this current resolution may not be adequate.
In order to print vascular structures a sacrificial temporary support material is used to define the vasculature around which a hydrogel matrix is deposited. The sacrificial material is removed and replaced with culture media or a similar fluid once the construct is built. The width of a printed line is the resolution limiting lateral dimension for 3D printing and hence the minimum dimension of the vascular channels. Currently 3D printed vascular structures, using both inkjet and extruded filament methods, have been fabricated from gelatin methacrylate (GelMA) using a poloxamer fugitive hydrogel (Pluronic F127) for the vasculature. The minimum feature size is ≈ 200 m in the x-y plane, the limiting factor is the high degree of wettability of the inks on the gelled deposit from their low contact angle; low contact angles lead to poor lateral resolution. Here we present results using a new approach and material formulation for the vascular material using formulated and modified gelatine based bioinks for both the vasculature and the hydrogel matrix. This allows better control of interfacial energies and leads to improved printed feature resolution. The approach also simplifies the design of the printer by allowing similar temperature control for both inks, unlike the case with poloxamer/GelMA inks where the two printed components must be delivered at different temperatures.
New results are also presented using a novel ultrahigh resolution inkjet printer that is capable of delivering drops with volumes of 1 fL and drop diameters close to 1 m. These are shown to be able to produce high resolution vascular tubes with diameter in the range 10 – 20 m, that can be seeded with endothelial cells.

Biography: 

Brian Derby is Professor of Materials Science in the School of Materials, University of Manchester, UK and Director of the Manchester Centre for Digital Fabrication http://www.eps.manchester.ac.uk/our-research/research-facilities/digital.... He is a Fellow of the Institution of Materials, Mining and Minerals and an Academician of the World Academy of Ceramics.
He studied for a BA in Natural Sciences at the University of Cambridge and a Ph.D. in Materials science also at the University of Cambridge. He was a European Space Agency research Fellow at CEA Grenoble and a Research Fellow in Engineering at the University of Cambridge before being appointed to a faculty position at the University of Oxford. He took up his position in Manchester in 1999.
His research has focussed on modelling and characterising the materials science of manufacturing processes and studying the formation and characterising the structures of interfaces in materials. He is a pioneer in the application of inkjet printing as a manufacturing process. In 2007 he was awarded the Edward de Bono medal as part of the Saatchi and Saatchi Awards for World Changing Ideas in recognition of his development of inkjet printing for applications in biology and medicine. He has received research funding from the EPSRC, BBSRC, MRC, Wellcome Trust, British Heart Foundation, The European Commission, Office for Naval Research (USA), Army Office of Research (USA) and directly from industry (including Rolls Royce, BAE Systems, Merck and Xaar).
He is Editor of the Springer Engineering Series Engineering Materials and Processes, Associate Editor of the Journal of the American Ceramic Society, Associate Editor of the Journal of Materials Science and Engineering C Biomimetic and Supramolecular Systems, and he is on the Editorial Board of the IoP journal Biofabrication.

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