Poly(ε-caprolactone)/Hydroxyapatite 3D Honeycomb Scaffolds for a Cellular Microenvironment Adapted to Maxillofacial Bone Reconstruction

Abstract

The elaboration of biomimetic materials inspired from the specific structure of native bone is one the main goal of tissue engineering approaches. To offer the most appropriate environment for bone reconstruction, we combined electrospinning and electrospraying to elaborate an innovative scaffold composed of alternating layers of polycaprolactone (PCL) and hydroxyapatite (HA). In our approach, the electrospun PCL was shaped into a honeycomb-like structure with an inner diameter of 160 μm, capable of providing bone cells with a 3D environment while ensuring the material biomechanical strength. After 5 days of culture without any differentiation factor, the murine embryonic cell line demonstrated excellent cell viability on contact with the PCL-HA structures as well as active colonization of the scaffold. The cell differentiation, as tested by RT-qPCR, revealed a 6-fold increase in the expression of the RNA of the Bglap involved in bone mineralization as compared to a classical 2D culture. This differentiation of the cells into osteoblasts was confirmed by alkaline phosphatase staining of the scaffold cultivated with the cell lineage. Later on, organotypic cultures of embryonic bone tissues showed the high capacity of the PCL-HA honeycomb structure to guide the migration of differentiated bone cells throughout the cavities and the ridge of the biomaterial, with a colonization surface twice as big as that of the control. Taken together, our results indicate that PCL-HA honeycomb structures are biomimetic supports that promotes in vitro osteocompatibility, osteoconduction, and osteoinduction and could be suitable for being used for bone reconstruction in complex situations such as the repair of maxillofacial defects.

The combination of a poly‐caprolactone/nano‐hydroxyapatite honeycomb scaffold and mesenchymal stem cells promotes bone regeneration in rat calvarial defects

“…In the present study, we first confirmed the in vitro cytocompatibility of this honeycomb PCL-nHA scaffold seeded with rat BM-MSCs by analyzing cell attachment, cell morphology, and spatial distribution. The cells completely covered the honeycomb PCL-nHA scaffold, and so there was no preference for a particular part of the honeycomb structure; this has previously been observed with C3H10T1/2 cells after 48 h of culture (Garcia Garcia et al, 2018). This complete coverage could be explained by the honeycomb pattern's promotion of extracellular matrix synthesis and upregulation of type II collagen (Eniwumide et al, 2014).…”

“…In the present study, the μCT parameters did prevent us from detecting the honeycomb PCL-nHA scaffold and thus from evaluating its rate of degradation over time. However, given that the mean ± SEM thickness of our honeycomb PCL-nHA scaffold was 31 ± 5 μm (Garcia Garcia et al, 2018), we can assume that it did not fill the bone defect (500 μm in thickness). Hence, the scaffold left space for bone synthesis, which might have contributed to the rapid bone construction (with a bone volume fraction of more than 80% after 8 weeks) relative to most of the scaffolds tested in the same model (Chamieh et al, 2016;Chen et al, 2019;Orbay et al, 2017;Son, Linh, Yang, & Lee, 2013;Wang et al, 2019;Wu et al, 2019;Zhang et al, 2016).…”

“…The mean diameter of the honeycomb cavities was 160 μm, and the honeycomb walls were 20 μm wide and 60 μm high. Thirteen layers of PCL (flow rate: 1.5 ml/h; needle-collector distance: 18 cm; voltage: 25 kV) and 13 layers of nHA (flow rate: 0.6 ml/h; needle-collector distance: 15.5 cm; voltage: 25 kV) were deposited alternately, as described previously (Garcia Garcia et al, 2018) (Figure 1a). After processing, the resulting membrane was peeled off from the honeycomb micropattern collector, transferred into six-well inserts (diameter: 12 mm; no membrane, Costar, Corning, France), disinfected in 70% ethanol for 1 h, and then rinsed three times with phosphate-buffered saline (PBS, Sigma-Aldrich).…”

“…When using honeycomb micropatterned collectors, the resulting scaffolds with controlled pore size mimic the hemiosteon structure (Nedjari et al, 2014). Using this process, a PCL scaffold integrating HA nanoparticles in the electrospraying steps with a honeycomb macrostructure (referred to henceforth as a “honeycomb PCL‐nHA scaffold”) proved to be cytocompatible, osteoconductive, and osteoinductive in vitro using the C3H10T1/2 cell line and organotypic culture (Garcia Garcia et al, 2018), but it has not yet been tested in vivo. This honeycomb PCL‐nHA scaffold was tested in this study for the first time in vivo to assess its bone reconstruction capacities.…”

Nanocomposite Polymer Scaffolds Responding under External Stimuli for Drug Delivery and Tissue Engineering Applications

“…A) Organotype culture of cells from a chicken bone embryo onto a honeycomb PCL/hydroxyapatite ELS scaffold produced by electrospinning/electrospraying onto a micropatterned collector. Reproduced with permission . Copyright 2018, American Chemical Society.…”