Development of an Additive Manufacturing Platform and Formulation of 3D Printable Hydrogel-Based Inks for Sensing and Environmental Applications
Creators: name: Finny, Abraham
Publisher: name: figshare
Year: 2022
Subjects: subject: 90301 Biomaterials
subject: FOS: Medical engineering
subject: 100708 Nanomaterials
subject: FOS: Nanotechnology
subject: 91205 Functional Materials
subject: FOS: Materials engineering
subject: 91202 Composite and Hybrid Materials
subject: Additive Manufacturing
subject: Environmental Chemistry
subject: 30107 Sensor Technology (Chemical aspects)
subject: FOS: Chemical sciences
subject: 100304 Industrial Biotechnology Diagnostics (incl. Biosensors)
subject: FOS: Industrial biotechnology
subject: 100101 Agricultural Biotechnology Diagnostics (incl. Biosensors)
subject: FOS: Agricultural biotechnology
subject: 100204 Environmental Biotechnology Diagnostics (incl. Biosensors)
subject: FOS: Environmental biotechnology
subject: 100402 Medical Biotechnology Diagnostics (incl. Biosensors)
subject: FOS: Medical biotechnology

description: Biopolymers and non-toxic synthetic polymers are some of the most appealing biomaterials for use in 3D bioprinting. While biopolymers are well known and broadly explored in many applications, their printability and the lack of suitable bioink composition that can be 3D printed remains a significant challenge. Choosing appropriate biopolymers and developing a selection guide for printing biocompatible hydrogels and biopolymer composites is crucial to print self-supporting 3D constructs successfully. Most importantly, analyzing the formulation criteria of bioinks and linking those criteria with the properties of the 3D-printed constructs is essential to the processing and utilizing of these materials for targeted applications such as tissue engineering, sensing, food industry, or consumer products applications. Therefore, the foremost task of this study is to understand the fundamental design characteristics of bioink formulations and develop a bioink selection guide that could be used as a universal tool for generating 3D constructs for targeted sensing and environmental applications. This includes the study of rheological, interfacial, mechanical, chemical, and degradation properties, as well as the behavior of the active components incorporated into hydrogel inks, which are crucial for printing complex and functional 3D structures. Several strategies and a general platform have been developed for printing functional hydrogel candidates to create fully 3D printable all-in-one sensors for monitoring physical and biological parameters for sensing and environmental remediation. <br> In the first strategy, the thermo-responsive property of gelatin is combined with alginate to form a shear-thinning hydrogel that could incorporate and maintain the activity of photoactive dyes with photocatalytic nanoparticles for use as UV sensors. In the second strategy, polyethyleneimine is added into a base hydrogel to enhance its physicochemical properties further and use the formulation as 3D printable adsorbents that have the capability to identify and remove heavy metal pollution. In the third strategy, cerium oxide nanoparticles were embedded within the hydrogel matrix to create colorimetric sensors for consumer applications. By tuning and modulating the hydrogel composition and the properties of individual components, we demonstrate strong interfacial bonding between layers, good shape fidelity, excellent stability, enhanced functionality, exceptional structural integrity, and excellent biocompatibility of the printed constructs. Collectively, these findings could help researchers select or develop suitable material compositions for bioprinting for a wide variety of target applications. The findings presented in this thesis demonstrate that by tuning the physicochemical properties of the hydrogel and adding carefully selected additives, it is possible to obtain standalone mechanically stable hydrogel constructs with new physical and functional properties such as: UV responsive features, target-induced color changing, and target binding properties for biorecognition, sensing and environmental remediation. In addition to specific examples of sustainable environmental sensing systems, the results also provide a selection guide for 3D printing hydrogels that can be used to additively manufacture a broad range of functional multi-composite constructs with strong interfacial bonding and stability.