Measuring Dimensionality of Cell-Scaffold Contacts of Primary Human Bone Marrow Stromal Cells Cultured on Electrospun Fiber Scaffolds

Published

January 1, 2023

Author(s)

Carl Simon Jr., Peter Bajcsy, Joe Chalfoun, Michael Paul Majurski, Mary C. Brady, Mylene Simon, Nathan Hotaling, Nick Schaub, Allison Horenberg, Piotr Szczypinski, Dongbo Wang, Veronica DeFelice, Soweon Yoon, Stephanie Florczyk

Abstract

The properties and structure of the cellular microenvironment can influence cell behavior. Sites of cell adhesion to the extracellular matrix (ECM) initiate intracellular signaling that direct cell functions such as proliferation, differentiation and apoptosis. Electrospun fibers are being advanced as tissue engineering scaffolds since they mimic the fibrous nature of native ECM proteins such as collagen, elastin and fibronectin. Culturing cells in fiber-based scaffolds can drive specific functions, such as the osteogenic differentiation of primary human bone marrow stromal cells (hBMSCs), by affecting cell shape and dimensionality. In order to probe this mechanism, cell-fiber contacts have been imaged to assess their shape and dimensionality. Fluorescent fiber scaffolds were made by spiking polymer solutions (poly(lactic-co-glycolic) acid, PLGA) with a fluorophore prior to electrospinning. Two types of fiber scaffolds were made: a medium fiber diameter (MMF) and a larger fiber diameter (MF). Fluorescent spuncoat PLGA films were made as a planar control (SC). hBSMCs were cultured on the fluorescent fibers and films and the i) hBMSCs, ii) fibers and iii) films were imaged by confocal fluorescence microscopy. Two fundamentally different image analysis approaches, one having geometrical assumptions and the other having statistical assumptions, were used to segment and analyze the 3D structure of cell-scaffold contacts. During culture in scaffolds (MMF, MF), the cells contacted the fibers in multiple planes over the surface of the cell. During culture on films (SC), contacts were confined to the bottom surface of the cell. Shape metrics indicated that cell-fiber contacts had greater dimensionality and greater 3D character than the cell-film contacts. These results indicate that cell adhesion site-initiated signaling may emanate from multiple planes over the cell surface during culture in fibers, as opposed to emanating only from the cell's bottom surface during culture on planar surfaces. These differences in cell-adhesion site geometry may affect signaling kinetics that control cell function in fiber-based scaffolds.

Citation

Journal of Biomedical Materials Research

Pub Type

Journals

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https://doi.org/10.1002/jbm.a.37449

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Keywords

regenerative medicine

Citation

Simon Jr., C. , Bajcsy, P. , Chalfoun, J. , Majurski, M. , Brady, M. , Simon, M. , Hotaling, N. , Schaub, N. , Horenberg, A. , Szczypinski, P. , Wang, D. , DeFelice, V. , Yoon, S. and Florczyk, S. (2023), Measuring Dimensionality of Cell-Scaffold Contacts of Primary Human Bone Marrow Stromal Cells Cultured on Electrospun Fiber Scaffolds, Journal of Biomedical Materials Research, [online], https://doi.org/10.1002/jbm.a.37449, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=934599 (Accessed April 25, 2024)