Guided assembly of cancer ellipsoid on suspended hydrogel microfibers estimates multi-cellular traction force

Abstract

Three-dimensional (3D) multi-cellular aggregates hold important applications in tissue engineering and in vitro biological modeling. Probing the intrinsic forces generated during the aggregation process, could open up new possibilities in advancing the discovery of tissue mechanics-based biomarkers. We use individually suspended, and tethered gelatin hydrogel microfibers to guide multicellular aggregation of brain cancer cells (glioblastoma cell line, U87), forming characteristic cancer ‘ellipsoids’. Over a culture period of up to 13 days, U87 aggregates evolve from a flexible cell string with cell coverage following the relaxed and curly fiber contour; to a distinct ellipsoid-on-string morphology, where the fiber segment connecting the ellipsoid poles become taut. Fluorescence imaging revealed the fiber segment embedded within the ellipsoidal aggregate to exhibit a morphological transition analogous to filament buckling under a compressive force. By treating the multicellular aggregate as an effective elastic medium where the microfiber is embedded, we applied a filament post-buckling theory to model the fiber morphology, deducing the apparent elasticity of the cancer ellipsoid medium, as well as the collective traction force inherent in the aggregation process.

Rheological and Biological Impact of Printable PCL‐Fibers as Reinforcing Fillers in Cell‐Laden Spider‐Silk Bio‐Inks

“…We used a glioblastoma cell line, U87 (U-87 MG), [15,32] to investigate the impact of PCL-fiber-reinforcement on cell performance in eADF4(C16) bio-inks. There are three critical steps that represent the different environmental conditions to which cells are exposed upon printing.…”

Biointerface Fiber Technology from Electrospinning to Inflight Printing

“…(d) Immunofluorescence images of an ellipsoid-on-string formed by human glioblastoma U87 cells along the suspended gelatin microfibers (green fluorescence: GFAP, a glial cytoskeletal marker; blue fluorescence: nuclei). Reprinted with permission from ref . Copyright 2021 IOP Science.…”

“…37 Furthermore, an aggressive form of brain cancer cell clusters was cultured on the scaffold, and rapid proliferation and guided migration were observed with highly aligned cell morphologies (Figure 6d). 15 Those cell adhesive fiber arrays with controllable spatial displacement could lead to future applications in creating aligned and stackable cell arrays with multiple cell types for disease modeling and basic biological research.…”

“…13 The fibril constituents of the ECM play a vital role in providing the biophysiological functionalities arising from the scale-dependent material chemistry, mechanics, and topography. Natural and biocompatible polymers, such as gelatin and collagen, could be used to produce ECMenvironment mimicking fiber structures for studying basic biological processes, such as cell migrations, 14 cancer developments, 15 and neuronal regeneration. 16 In addition, functional polymers with sensing capabilities have been explored to build bioelectronic and wearable sensors.…”