3D Printed Functional Materials and Devices and Applications in AI-powered 3D Printing on Moving Freeform Surfaces

Abstract

The capability of 3D printing a diverse palette of functional inks will enable the mass democratization of manufactured patient-specific wearable devices and smart biomedical implants for applications such as health monitoring and regenerative biomedicines. These personalized wearables could be fabricated via in situ printing --- direct printing of 3D constructs on the target surfaces --- at ease of the conventional fabricate-then-transfer procedure. This new 3D printing technology requires functional (e.g., conductive and viscoelastic) inks and devices (e.g., wearable and implantable sensors) that are compatible with in situ printing, as well as the assistance of artificial intelligence (AI) to sense, adapt, and predict the state of the printing environment, such as a moving hand and a dynamically morphing organ. To advance this in situ printing technology, this thesis work is focused on (1) the development of functional materials and devices for 3D printing, and (2) the AI-assisted 3D printing system. To extend the palette of 3D printable materials and devices, on-skin printable silver conductive inks, hydrogel-based deformable sensors, and transparent electrocorticography sensors were developed. As with the AI for in situ 3D printing, solutions for four types of scenarios were studied (with complexity from low to high): (1) printing on static, planar substrates without AI intervention, with a demonstration of fully printed electrocorticography sensors for implantation in mice; (2) printing on static, non-planar parts with open-loop AI, with a demonstration of printing viscoelastic dampers on hard drives to eliminate specific modes of vibration; (3) printing on moving targets with closed-loop and predictive AI, with demonstrations of printing wearable electronics on a human hand and depositing cell-laden bio-inks on live mice; (4) printing on deformable targets with closed-loop and predictive AI, with demonstrations of printing a hydrogel sensor on a breathing lung and multi-material printing on a phantom face. We anticipate that this convergence of AI, 3D printing, functional materials, and personalized biomedical devices will lead to a compelling future for on-the-scene autonomous medical care and smart manufacturing.