Acoustic patterning of microcapillary networks for 3D vascularized in vitro models

This thesis explores an innovative biofabrication technology, specifically, contactless sound patterning and it is organized in three main parts. The initial two chapters establish a literature review of cutting-edge strategies in tissue engineering and regenerative medicine. The first chapter introduces the synergistic use of 3D bioprinting and nano-biomaterials, employing nano-sized bioactive materials within bio-inks formulation to induce varied cellular responses. Despite the widespread use of 3D bioprinting, inherent limitations hinder its clinical translation. The second chapter delves into the literature review on the state of the art of acoustic manipulation, presenting various devices and methods applicable in biomedical engineering and in vitro tissue modeling. Building upon this foundation, the thesis moves on the exploration of sound patterning as a chosen biofabrication technique. Sound patterning is explored for its versatility in spatially organizing cells, addressing biofabrication challenges such as high cell packing density, mildness of the process and rapidly creating 3D in vitro cellular morphologies. Subsequent chapters show the application of sound patterning in various in vitro models. Firstly, a vascularized tumor model for drug testing is developed by utilizing sound patterning to create reproducible cellular orchestration in a ring-like capillary structure which is later combined with a tumor mass. The model allows for image analysis-based readouts. Through live-imaging of the capillary structures, pro- or anti- angiogenic responses induced by the treatments can be detected. The following chapter explores the potential of sound-patterned capillaries in guiding neuronal growth within a 3D in vitro model of the peripheral neurovascular system. The sound patterned vascular layer accelerates neurite growth and induces their organization in multiplanar networks. The next chapter investigates cellular changes induced by the enhanced cell density achieved through sound patterning. Here, proteomic analysis is employed to shade light on the differential proteomic profile of microcapillary networks which self-assembled after sound patterning compared to their static counterpart. Finally, in the appendix, I discuss preliminary approaches to generate spatially patterned perfusable capillary networks, strategies which may be further explored in the future. Utilizing fast prototyping technologies such as computer numerical control (CNC) milling and fused deposition modeling (FDM) 3D printing, new labware solutions are created. This multidisciplinary research contributes with new insights into sound patterning as a promising biofabrication approach, for spatial control of cellular organization, and the development of advanced in vitro systems for tailored therapeutic applications.