9 - High-resolution 3D printing for healthcare underpinned by small-scale fluidics

Abstract

In this chapter we concentrate on recent developments in small-scale fluidics assisted high-resolution (<10μm) 3D printing technologies and their potential transformative impact and applications in healthcare. We start by outlining the clinical context and healthcare needs driving some of the most exciting developments in the high-resolution printing and healthcare manufacture, which are poised to underpin the growth of major new health and care paradigms such as personalized medicine and medical devices; minimally invasive surgical interventions and sensors; biorobotics, bionics and human-machine interfaces enabled by haptics technologies; sensing and stimulation devices; and theranostic and bioresorbable medical devices. This is followed by a brief review of a few techniques for 3D printing at high-resolution, including direct-write and electrohydrodynamic printing where small (micro and nano) scale fluidics plays a vital role in improving reliability and achieving resolutions at the limit of current photolithographic techniques. Next we discuss the fundamentals of small-scale flows and materials considerations in designing “inks” for 3D printing. This includes expounding on the role of two key parameters, ink rheology and surface energy, in deciding the printing resolution. Then we discuss some healthcare related exemplar structures that have exploited high-resolution 3D printing and, in particular, emphasize the unique features of high-resolution printing that suit these applications. These include discussion on electronic interconnects and healthcare sensors, bio-scaffolds and their functional properties, cell signaling and the role of site-specific materials deposition for biology-on-a-chip type applications. Lastly, we will provide a perspective on future developments in the technology and its potential impact on shaping the future of healthcare applications such as miniature wearable and implantable sensing, (personalised) implantable devices, soft robotics and haptics, etc.