Periodic Reporting for period 3 - 3DPartForm (3D-printing of PARTiculate FORMulations utilizing polymer microparticle-based voxels)
Periodo di rendicontazione: 2022-08-01 al 2024-01-31
The demand for solutions in digital health, cellular materials and microsystems requires reconsidering how polymer materials are made and multiple functions as well as the time axis (e.g. the material’s ability to be adaptive and stimuli-responsive over its life cycle) properly integrated. Based on the 3DPartForm project’s motto “Material innovations arise from the way materials are made”, the project’s approach towards this goal is to come up with a novel design concept where polymer materials will be able to collect, process and release signals and information in a smart fashion. Most importantly, multimaterials will be designed such that one specific function can be triggered by multiple stimuli, and one specific stimulus can induce multiple functions. With that, 4D polymer materials will be obtained for the first time that are highly integrated, multifunctional, reprogrammable, scalable, and able to sense, guide and manipulate information. The basis for this approach are adaptive and stimuli-responsive, microscopic hydrogel particles that will be assembled into hierarchical systems based on additive manufacturing – metaphorically speaking in a LEGO®-like fashion. Thus, the project’s contribution to moving forward the state of the art in polymer materials design and processing methods will be manifold. Exemplarily, functionality of polymer materials will be embedded on the building block level to avoid elaborate, costly post processing. Further, by using building blocks that are not liquid as in established 3D printing methods based on polymer melts or resins but made of pre-polymerized particles, design flexibility and thus combinations of materials and functions is greatly enhanced opening up new possibilities in tailored material solutions, which will be a game changer for wearable materials, biomimetics, and artificial organ design.
The importance of the project for society lies in its broadness of applicability of the materials that can be developed by 3DPartForm’s unique combination of material basis and processing technology. Microgels have been chosen as building blocks due to their successful usage as platform for biosensing or as cell-like environment for cell-free protein synthesis and enzymatic cascades - all examples that have been explored by the PI’s research group. Building up hierarchical assemblies of such versatile building blocks will provide a path towards material composites or so-called cellular materials that make the jump to length scales that are significant for the important field of human-machine integration, intelligent biomedical systems, and hybrid tissue of artificial and natural entities, for instance. By implementing sensory molecules, nanoparticles and functional microgel building blocks, (bio-)chemical information and signals will be processable in such a complex, cross-scale environment and, in perspective, even provide the means to control system properties based on feedback loops. As a long-term perspective, the combination of cellular materials and sensing will form the basis for rational materials design and the development of biomedical systems that are optimally adapted to their environment and a user’s/patient’s needs.
The importance of the project for society lies in its broadness of applicability of the materials that can be developed by 3DPartForm’s unique combination of material basis and processing technology. Microgels have been chosen as building blocks due to their successful usage as platform for biosensing or as cell-like environment for cell-free protein synthesis and enzymatic cascades - all examples that have been explored by the PI’s research group. Building up hierarchical assemblies of such versatile building blocks will provide a path towards material composites or so-called cellular materials that make the jump to length scales that are significant for the important field of human-machine integration, intelligent biomedical systems, and hybrid tissue of artificial and natural entities, for instance. By implementing sensory molecules, nanoparticles and functional microgel building blocks, (bio-)chemical information and signals will be processable in such a complex, cross-scale environment and, in perspective, even provide the means to control system properties based on feedback loops. As a long-term perspective, the combination of cellular materials and sensing will form the basis for rational materials design and the development of biomedical systems that are optimally adapted to their environment and a user’s/patient’s needs.
The roadmap towards these materials is a multi-step process. Starting from developing a material library for microgel (= building block) fabrication (1), the preparation of exactly these microgels in sufficient amounts for subsequent across-scale material manufacturing that exceed available microfluidic technology will be in focus (2). In parallel, first steps towards an assembly platform of individual microgels will be discussed followed by the preparation of 3D materials with a focus on light guiding and processing (3).
As a basis in polymer material design, various inter-crosslinking mechanisms have been identified to yield optimal connectivity among multi-particle/multi-microgel assemblies. As a material basis for building block design, both natural and synthetic monomers and macromers have been explored. To further expand the material library, methods for fabricating microgels were developed, which enable processing fast-gelling precursors into homogeneous microgels via emulsion droplet coalescence, and extend the microgels' functionality by incorporation of various additives. For proof-of-concept and easier handling of material building blocks, initial studies were carried out using macroscopic hydrogel-based building blocks before down-scaling towards micron-sized building blocks to improve the local resolution of functionality and thus the degree of system integration. As both types of building block sizes could be successfully inter-crosslinked by hand, the focus has been then on a novel AM platform, allowing for the controlled, hierarchical assembly of the building blocks. Working towards these 2D and eventually 3D assemblies, the scale-up of hydrogel particle suspensions from milliliter- to liter-scale has been studied in depth developing parallelized microfluidics in 3D-printed microflow cells. For maximized signal transmission in hierarchical hydrogel particle assemblies, e.g. for the transmission of light, besides building block properties themselves as well as the inter-crosslinking stability as another factor, the size and interfacial area of the inter-crosslinked particle-particle interface needs to be considered. For this reason, with Stop-flow Lithography (SFL), a process is currently being established that, in contrast to conventional droplet microfluidics, allows for fabricating anisotropic hydrogel microparticles. The results and new insights gathered form a promising basis to successfully implement a new path in polymer material design and processing from which not only materials scientists, but also life science and engineering will greatly benefit.
As a basis in polymer material design, various inter-crosslinking mechanisms have been identified to yield optimal connectivity among multi-particle/multi-microgel assemblies. As a material basis for building block design, both natural and synthetic monomers and macromers have been explored. To further expand the material library, methods for fabricating microgels were developed, which enable processing fast-gelling precursors into homogeneous microgels via emulsion droplet coalescence, and extend the microgels' functionality by incorporation of various additives. For proof-of-concept and easier handling of material building blocks, initial studies were carried out using macroscopic hydrogel-based building blocks before down-scaling towards micron-sized building blocks to improve the local resolution of functionality and thus the degree of system integration. As both types of building block sizes could be successfully inter-crosslinked by hand, the focus has been then on a novel AM platform, allowing for the controlled, hierarchical assembly of the building blocks. Working towards these 2D and eventually 3D assemblies, the scale-up of hydrogel particle suspensions from milliliter- to liter-scale has been studied in depth developing parallelized microfluidics in 3D-printed microflow cells. For maximized signal transmission in hierarchical hydrogel particle assemblies, e.g. for the transmission of light, besides building block properties themselves as well as the inter-crosslinking stability as another factor, the size and interfacial area of the inter-crosslinked particle-particle interface needs to be considered. For this reason, with Stop-flow Lithography (SFL), a process is currently being established that, in contrast to conventional droplet microfluidics, allows for fabricating anisotropic hydrogel microparticles. The results and new insights gathered form a promising basis to successfully implement a new path in polymer material design and processing from which not only materials scientists, but also life science and engineering will greatly benefit.
3DPartForm utilizes an interdisciplinary approach to develop a new class of polymer materials with intrinsic time axis based on the hierarchical assembly of building blocks with arbitrary configuration of their individual dynamic and stimuli-responsive properties. Thus, the expected results will move more than one field of research forward. In the area of scaling up microfluidic production, 3D-printed microfluidic devices combining two levels of scale-up (parallel emulsification and so-called droplet splitting) will enable a broad audience to use microfluidics for material design and analytics. The monolithic device fabrication based on PµSL instead of conventional combined photo- and soft lithography will provide the basis for scalable and robust microfluidics, thus addressing a key demand in the microfluidics and materials science community. Microgel-based building blocks manufactured by these devices will be assembled in 2D and eventually 3D by a novel AM platform, which is expected to become a standard in the design of discontinuous soft matter and integrated cellular materials. As a long-term perspective, the manually operated AM platform will be automated and commercialized, e.g. in an ERC PoC project.
Generally, the ERC project has been strongly application-driven. Thus, it is the aim to extend the focus of the project to also provide a general understanding and eventually guidelines for discontinuous soft matter design and its assembly (e.g. mechanical cohesion, information flow across building block interfaces, behavior of material assemblies upon local shrinkage, swelling, material ageing).
Generally, the ERC project has been strongly application-driven. Thus, it is the aim to extend the focus of the project to also provide a general understanding and eventually guidelines for discontinuous soft matter design and its assembly (e.g. mechanical cohesion, information flow across building block interfaces, behavior of material assemblies upon local shrinkage, swelling, material ageing).