Title : Determining the geometric factors governing the growth of mesenchymal cells into a 3D structure
Abstract:
INTRODUCTION: Cell culture techniques are essential for studying cellular behavior. However, traditional two-dimensional (2D) cultures do not fully capture the complexity of an in vivo environment due to the lack of extracellular matrix (ECM) interactions and limited structural complexity and arrangement. This study investigates the 3D structural characteristics of metallic lattice structures that influence mesenchymal cell growth and their implications for implant integration. By understanding how tissues grow within lattice implants in vivo, we can optimize scaffold designs to enhance cellular proliferation and tissue regeneration.
METHODS: A monolayer culture of mesenchymal cells (Kusa 4b10) was initially established on a GelMa hydrogel substrate, then a 3D-printed G23 titanium lattice was placed on top of the monolayer of cells and maintained for 28 days. Ten lattices of different designs (three replicates each) were evaluated in one experiment, which was repeated twice, i.e. Experiments 1 and 2. Cell attachment and proliferation into the lattices were assessed following transfer to a new cell culture plate using a CCK-8 assay at 450 nm. Separately, the digital design files used in the manufacturing of each lattice structure were analyzed in 3D Slicer and ImageJ (BoneJ plugin) to quantify various structural parameters, including element thickness (El_Th), element separation (El_Sp), ellipsoid factor (EF), degree of anisotropy (DA), porosity (P.O), and connectivity density (Conn.D). These factors were then plugged into a linear mixed model to assess their impact on cellular growth into the lattices, expressed as the CCK-8 (OD 450 nm) to SA (cm2) ratio.
RESULTS: Amongst various parameters by which a lattice structure can be mathematically described, key parameters that influenced cell ingrowth were El_Th, EF and Po.
DISCUSSION & CONCLUSIONS: These results align with previous findings, such as those demonstrating that a spacing and high porosity facilitate cell migration and osseointegration. Previous studies have also shown the positive impact of porosity on the performance of porous metal scaffolds.
