A simple rocker‐induced mechanical stimulus upregulates mineralization by human osteoprogenitor cells in fibrous scaffolds

Abstract

Biodegradable electrospun polycaprolactone scaffolds can be used to support bone‐forming cells and could fill a thin bony defect, such as in cleft palate. Oscillatory fluid flow has been shown to stimulate bone production in human progenitor cells in monolayer culture. The aim of this study was to examine whether bone matrix production by primary human mesenchymal stem cells from bone marrow or jaw periosteal tissue could be stimulated using oscillatory fluid flow supplied by a standard see‐saw rocker. This was investigated for cells in two‐dimensional culture and within electrospun polycaprolactone scaffolds. From day 4 of culture onwards, samples were rocked at 45 cycles/min for 1 h/day, 5 days/week (rocking group). Cell viability, calcium deposition, collagen production, alkaline phosphatase activity and vascular endothelial growth factor secretion were evaluated to assess the ability of the cells to undergo bone differentiation and induce vascularisation. Both cell types produced more mineralized tissue when subjected to rocking and supplemented with dexamethasone. Mesenchymal progenitors and primary human mesenchymal stem cells from bone marrow in three‐dimensional scaffolds upregulated mineral deposition after rocking culture as assessed by micro‐computed tomography and alizarin red staining. Interestingly, vascular endothelial growth factor secretion, which has previously been shown to be mechanically sensitive, was not altered by rocking in this system and was inhibited by dexamethasone. Rocker culture may be a cost effective, simple pretreatment for bone tissue engineering for small defects such as cleft palate.

3D Printing of Bone Grafts for Cleft Alveolar Osteoplasty – In vivo Evaluation in a Preclinical Model

“…This might be the reason, why, up to now, only a few materials were tested for the treatment of such defects and most studies concentrate on secondary bone grafting (Seifeldin, 2016). These materials include hydroxyapatite granules (Korn et al, 2014(Korn et al, , 2017, bio-ceramics coated with bovine collagen and dipyridamole (Lopez et al, 2018), tricalcium phosphates (TCP) (Janssen et al, 2014;Berger et al, 2015), demineralized bone matrix (Francis et al, 2013), thermoplastic poly-ε-caprolactone (PCL) (Ahn et al, 2018;Puwanun et al, 2018) or a β-TCP/PCL composite (Raúl et al, 2019). In a recent review, Martín-del-Campo et al (2019) suggested several biomaterial-based strategies which have high potential for cleft repair.…”

Mimetic Hierarchical Approaches for Osteochondral Tissue Engineering

“…Osteogeneicity of these cells is confirmed when cultured on porous scaffolds yielding bone-like tissue [35,36]. Importantly, these cells were also confirmed to have mesenchymal multipotency, demonstrated by single-cell lineage analysis [37].…”

Investigation of Conjunctival Fibrosis Response Using a 3D Glaucoma Tenon's Capsule + Conjunctival Model

“…A ''see-saw'' motion rocker was used to apply shear stress, because it is an established method used in numerous credible studies to mimic fluid shear stress, [19][20][21][22] including use with 3D culture. 23 The method enables a high throughput, which was advantageous for this study, allowing us to easily expose many samples at once to 1 hour per day of shear stress during culture in 48-well plates. The method also has a low cost and is easy to establish.…”

“…Because the 3D samples were thin (approximately 150 lm) with a low collagen concentration (3 mg/mL), we can be confident that shear stress would have passed through sample pores, previously estimated to measure between 2.2 and 1.1 lm for 1-to 4-mg/mL collagen hydrogels. 24 Puwanun et al 23 previously stimulated bone cells in rigid polycaprolactone (PCL) electrospinning scaffolds (width 15 mm 3 length 35 mm 3 thickness 390 lm) and found enhancement of mineralization due to the shear stress exerted by a see-saw motion rocker. This occurred throughout the full thickness of the scaffold, as evidenced by micro computed tomography scan images.…”

“…This occurred throughout the full thickness of the scaffold, as evidenced by micro computed tomography scan images. 23 Furthermore, surface shear stress has previously been applied via fluid movement across the top of 3 mg/mL collagen hydrogels successfully, in addition to interstitial flow, using microfluidic perfusion systems. 25,26 The fluid shear stress generated in our 3D model is calculated as previously described 19 to be 0.065 Pa, based on fluid viscosity (10 À3 Pa s), a maximum 78 flip angle, 1.6-mm fluid depth, 11-mm well length, and 12-second cycle (5 rpm).…”