Towards an in vitro model of the glomerular barrier unit with an innovative bioassembly method

Coaxial cell printing of a human glomerular model: anin vitroglomerular filtration barrier and its pathophysiology

Much effort has been expended in emulating the kidney's glomerular unit because of its limitless potential in the field of drug screening and nephrotoxicity testing in clinics. Herein, we fabricate a functional bilayer glomerular microvessel-on-a-chip that recapitulates the specific arrangement of the glomerular endothelial cell, podocyte layers, and the intervening glomerular basement membrane (GBM) in a single step. Our perfusable chip allows for the co-culture of monolayer glomerular endothelium and podocyte epithelium, which display mature functional markers of glomerular cells, and their proper interactions produce GBM proteins, which are the major components of the GBMin vivo. Furthermore, we test the selective permeability capacity, a representative hallmark function of the glomerular filtration barrier. Lastly, we evaluate the response of our glomerular model to Adriamycin- and hyperglycemia-induced injury to evaluate its applicability for drug screening and glomerular disease modeling.

Vascularization of Cell-Laden Microfibres by Femtosecond Laser Processing

To face the increasing demand for organ transplantation, currently the development of tissue engineering appears as the best opportunity to effectively regenerate functional tissues and organs. However, these approaches still face the lack of an efficient method to produce an efficient vascularization system. To answer these issues, the formation of an intra-volume channel within a three-dimensional, scaffold free, mature, and cell-covered collagen microfibre is here investigated through laser-induced cavitation. An intra-volume channel was formed upon irradiation with a near-infrared, femtosecond laser beam, focused with a high numerical aperture lens. The laser beam directly crossed the surface of a dense and living-cell bilayer and was focused behind the bilayer to induce channel formation in the hydrogel core while preserving the cell bilayer. Channel formation was assessed through confocal microscopy. Channel generation inside the hydrogel core was enhanced by the formation of voluminous cavitation bubbles with a lifetime longer than 30 s, which also improved intra-volume channel durability. Twenty-four hours after laser processing, cellular viability dropped due to a lack of sufficient hydration for processing longer than 10 min. However, the processing automation could drastically reduce the cellular mortality, this way enabling the formation of hollowed microfibres with a high density of living-cell outer bilayer.

Tissue Engineering and Regenerative Medicine 2019: The Role of Biofabrication-A Year in Review

Despite its relative youth, biofabrication is unceasingly expanding by assimilating the contributions from various disciplinary areas and their technological advances. Those developments have spawned the range of available options to produce structures with complex geometries while accurately manipulating and controlling cell behavior. As it evolves, biofabrication impacts other research fields, allowing the fabrication of tissue models of increased complexity that more closely resemble the dynamics of living tissue. The recent blooming and evolutions in biofabrication have opened new windows and perspectives that could aid the translational struggle in tissue engineering and regenerative medicine (TERM) applications. Based on similar methodologies applied in past years' reviews, we identified the most high-impact publications and reviewed the major concepts, findings, and research outcomes in the context of advancement beyond the state-of-the-art in the field. We first aim to clarify the confusion in terminology and concepts in biofabrication to therefore introduce the striking evolutions in three-dimensional and four-dimensional bioprinting of tissues. We conclude with a short discussion on the future outlooks for innovation that biofabrication could bring to TERM research.