Flow perfusion rate modulates cell deposition onto scaffold substrate during cell seeding

Abstract

The combination of perfusion bioreactors with porous scaffolds is beneficial for the transport of cells during cell seeding. Nonetheless, the fact that cells penetrate into the scaffold pores does not necessarily imply the interception of cells with scaffold substrate and cell attachment. An in vitro perfusion system was built to relate the selected flow rate with seeding efficiency. However, the in vitro model does not elucidate how the flow rate affects the transport and deposition of cells onto the scaffold. Thus, a computational model was developed mimicking in vitro conditions to identify the mechanisms that bring cells to the scaffold from suspension flow. Static and dynamic cell seeding configurations were investigated. In static seeding, cells sediment due to gravity until they encounter the first obstacle. In dynamic seeding, 12, 120 and 600 flow rates were explored under the presence or the absence of gravity. Gravity and secondary flow were found to be key factors for cell deposition. In vitro and in silico seeding efficiencies are in the same order of magnitude and follow the same trend with the effect of fluid flow; static seeding results in higher efficiency than dynamic perfusion although irregular spatial distribution of cells was found. In dynamic seeding, 120 provided the best seeding results. Nevertheless, the perfusion approach reports low efficiencies for the scaffold used in this study which leads to cell waste and low density of cells inside the scaffold. This study suggests gravity and secondary flow as the driving mechanisms for cell-scaffold deposition. In addition, the present in silico model can help to optimize hydrodynamic-based seeding strategies prior to experiments and enhance cell seeding efficiency.

Modeling the flow and mass transport in a mechanically stimulated parametric porous scaffold under fluid-structure interaction approach

“…Previous studies oriented their investigation on only CFD models for analyzing these type of variables that cannot be assessed by means of experiments [6][7][8][9][10][11]15,13,14,12]. Only recent works apply the FSI technique for studying the complex hydrodynamic environment within a scaffold [23,27,[38][39][40].…”

“…Computational fluid dynamics (CFD) has been widely used for solving and determining the shear stress distribution of idealized [3,4] and complex microCT-based scaffold structures [5][6][7][8][9][10][11][12]. Recently, a validation of such models using particle image velocimetry (PIV) has been proposed with the aim of investigating how fluid flow conditions modulate cell motion and deposition during perfusion [13][14][15].…”

Permeability versus Design in TPMS Scaffolds

“…Therefore, good permeability of the scaffold, translated to the properties of the structure, means the right pore size distribution, high pore interconnectivity, and sufficient porosity [7,8,9]. Furthermore, permeability affects the magnitude of pressure and shear forces inside scaffolds, identified as potential stimuli for cellular differentiation or functional adaptation, for cell seeding efficiency and in vivo new tissue formation [10,11,12].…”

Cell marbles: A novel cell encapsulation technology by wrapping cell suspension droplets using electrospun nanofibers for developmental engineering

“…Cell marbles (0.5-2.0 mm in diameter) were produced by wrapping different types of cells suspended in culture media with electrospun nanofibers. Microscopic analysis of the CMs stored in mineral oil at room temperature for 10 minutes indicated that almost all of the initially encapsulated cells precipitated either at the bottoms of the CMs or on the up-inclined inner surfaces of the cloaks driven by gravity (Campos Marín et al, 2018;Scarritt et al, 2018).…”