Ong, L. J. Y. | Search bioRxiv

bioRxiv2025

A Patient-Specific 3D Printed Carotid Artery Model Integrating Vascular Structure, Flow and Endothelium Responses

The progression of atherosclerosis is driven by the interplay between vascular anatomy, hemodynamic forces, and endothelial responses. However, existing in vitro vascular models have yet to integrate all these elements into a cohesive, patient-specific system. Here, we present the first instance of direct 3D printing of a miniaturized, patient-specific carotid artery model that recapitulates anatomical-dependent hemodynamic changes and vascular cell remodeling. Phase-contrast MRI scans from a healthy donor were used to generate miniaturized 3D carotid artery models, which were analyzed via computational fluid dynamics (CFD) and particle imaging velocimetry (PIV) to validate the preservation of physiological hemodynamic properties. Using digital light processing (DLP) 3D printing, we fabricated the miniaturized carotid artery vessel using GelMA, containing embedded human aortic smooth muscle cells and an endothelialized lumen. Perfusion culture replicated physiological arterial shear stress of up to 10 dynes cm-{superscript 2}, resulting in differential endothelial cell alignment and inflammatory monocyte adhesion corresponding to laminar and turbulent flow regions within the carotid artery. This model serves as a powerful platform to investigate how anatomical variation influences susceptibility to atherosclerosis through its impact on local flow dynamics.

bioengineering↗

bioRxiv2023

Localized oxygen control in a microfluidic osteochondral interface model recapitulates bone-cartilage crosstalk during osteoarthritis

Osteoarthritis (OA) is characterized by the dysregulation of the osteochondral interface between bone and cartilage. In vitro models that accurately mimic this interface hold great potential for understanding OA pathophysiology and screening therapeutic agents. Presently, research efforts have focused on emulating heterogeneity in structural and mechanical attributes of the extracellular matrix (ECM) at the osteochondral interface. However, the precise simulation of differential oxygen gradients experienced by chondrocytes and osteoblasts in vivo remains a substantial obstacle for modeling osteo-chondral interactions effectively. To overcome this limitation, we show that micropatterned granular hydrogels, which are small microgel particles swelled in liquid culture media to create a shear-yielding jammed-packed solid, can be used to control the delivery of oxygen scavenging agents in a simple and scalable manner. Hypoxic granular hydrogels formulated with Oxyrase could maintain <1% oxygen concentration in a conventional cell culture incubator. Primary human chondrocytes maintained in the hypoxic hydrogels expressed a more anabolic phenotype similar to those cultured in a hypoxic incubator. The granular hydrogels can be readily patterned in a microfluidic device to generate a localized hypoxic environment, mimicking the differential oxygen levels at the osteochondral tissue interface (i.e. osteoblast at 20% and chondrocyte at 2% oxygen). Using this microfluidic coculture model, we paired healthy human chondrocytes with osteoblasts isolated from non-sclerotic and sclerotic subchondral bone to investigate how oxygen environment modulates osteoblast-chondrocyte crosstalk during OA. In a differential oxygen environment, the osteoblast-chondrocyte co-culture model showed sclerotic osteoblasts inducing chondrocyte collagen expression changes through increased MMP13 and ADAM15 production, unlike in a uniform normoxic oxygen environment, where the change was driven by altered collagen gene expression favoring Type I over Type II collagen. Furthermore, differential oxygen conditions enabled the identification of extensive transcriptional alterations induced by sclerotic osteoblasts, which involved inflammatory NF-{kappa}{beta}, TGF-{beta}/BMP, and IGF signaling pathways, that was otherwise not detectable in a uniform normoxic co-culture. The microfluidic model with localized oxygen variations effectively mimics physiologically relevant osteoblast-chondrocyte crosstalk, providing valuable insights into OA pathophysiology.

bioengineering↗