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Description
The blood–brain barrier (BBB) is a highly specialized neurovascular interface that regulates the selective exchange of molecules between the bloodstream and the central nervous system, playing a critical role in maintaining brain homeostasis (Cruz et al., 2023). Despite advances in in vitro modeling, many existing BBB models lack the structural and functional complexity necessary to fully replicate biomimetic structure. In this study, we propose an embedded 3D bioprinting approach to develop constructs with perfusable endothelialized microchannels to recapitulate the biomimetic structure of the BBB. Our strategy employes high-resolution extrusion-based printing of a sacrificial bioink within a neural cell laden supportive and biocompatible hydrogel (Afghah et al., 2020). The removal of the sacrificial bioink from the crosslinked construct enables the formation of perfusable endotheliazed microchannels, mimicking brain capillary structures. This approach offers a promising platform for applications in drug screening, neurodegenerative disease modeling, and translational neuroscience research.
MATERIALS AND METHODS
A vascularized structure was digitally designed and printed within a biocompatible hydrogel matrix. This supportive matrix, composed of Gelatin Methacryloyl (GelMA) was modified with Xanthan gum to improve the shear-thinning property. A 20% Pluronic F127 (PF127) solution served as sacrificial ink for printing vascularized microchannels. Following the embedded bioprinting process within a GelMA support matrix, the construct was crosslinked under UV light to stabilize its structure. The sacrificial PF127 ink was subsequently removed to create perfusable microchannels. These channels were then perfused with endothelial cells to develop biomimetic endothelialized microchannels. Live/dead assays and structural imaging confirmed both the biocompatibility and fidelity of the endothelial microchannels, demonstrating the potential of the construction for BBB modeling.
RESULTS AND DISCUSSION
Embedded 3D bioprinting technology allowed development of constructs with perfusable microchannels. The hollow channels within the construct remained intact and were effectively seeded with endothelial cells. Live/dead staining confirmed high viability of endothelial cells within the perfused microchannels. Confocal microscopy images revealed well-defined channel architecture and continuous endothelial cell lining. The GelMA hydrogel maintained structural stability while providing a biocompatible matrix for cell growth and neural differentiation.
CONCLUSIONS
The proposed embedded 3D bioprinting approach enabled the development of the constructs with perfusable endothelialized microchannels that effectively recapitulate the biomimetic structure of BBB in a brain-biomimetic structure. This advanced model demonstrates significant potential for enhancing 3D bioprinted blood-brain barrier platforms in neurovascular research and pharmaceutical screening applications.
REFERENCES
Cruz, E. M., Machado, L. S., Zamproni, L. N., Bim, L. V., Ferreira, P. S., Pinto, L. A., Pessan, L. A., Backes, E. H., & Porcionatto, M. A. (2023). A Gelatin Methacrylate-Based Hydrogel as a Potential Bioink for 3D Bioprinting and Neuronal Differentiation. Pharmaceutics, 15(2).
Afghah, F., Altunbek, M., Dikyol, C., & Koc, B. (2020). Preparation and characterization of nanoclay-hydrogel composite support-bath for bioprinting of complex structures. Scientific Reports, 10(1).
ACKNOWLEDGEMENTS
This study is supported by the Scientific and Techno-logical Research Council of Turkey (TUBITAK) Grant Number 22AG051. The authors acknowledge Sabanci University and Sabanci University Nanotechnology Research and Application Center (SUNUM).
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