The Variability in Cytocompatibility and Bone Conduction Based on Different Pore Size and Porosity of n-HA/PA66 Composite Scaffolds

Abstract

As porous materials, nano-hydroxyapatite/polyamide 66 (n-HA/PA66) composite scaffolds with both desirable bioactivity and good mechanical properties showed great potential to reconstruct the bone defect. Moreover, the pore size and porosity played a key role in the scaffold architecture and cell or bone ingrowth. To investigate the cytocompatibility of different pore size and porosity of n-HA/PA66 composite scaffolds on differentiation and cytocompatibility of osteogenically induced bone marrow-derived mesenchymal stem cells (BMSCs) and bone conduction in repairing the calvarial critical size defect of Sprague-Dawley rats in vivo, we evaluated three kinds of n-HA/PA66 composite scaffolds according to the pore size and porosity in this study (group A: mean pore size was 214 ± 107.3 μm, and more than 70% were arranged in 100–300 μm; group B: material mean pore size was 375 ± 132.2 μm, and about 60% were distributed in 300–500 μm; group C: mean pore size was 533 ± 169.4 μm, and more than 60% were in 400–700 μm). Osteogenically induced BMSCs were seeded in the three types of n-HA/PA66 material and cultured in vitro, and the variability on cell adhesion, growth, proliferation, osteogenic differentiation was analyzed using scanning electron microscopy alkaline phosphatase (ALP) and collagen type I (COL I) immunohistochemical staining, as well as quantitative real-time PCR (qRT-PCR) analysis on the osteogenesis-related gene expression (alkaline phosphatase, COL I), was done. Three group matrices/BMSC composites were implanted into the cranial defect of Sprague-Dawley rats. The differentiations of osteogenesis in vivo were then evaluated by histological and qRT-PCR analysis on mRNA levels of OPG and RANKL after 4 and 8 weeks, respectively. The in vitro and in vivo results showed that the group B n-HA/PA66 scaffold was more suitable for osteogenically induced BMSC proliferation, differentiation in vitro, and bone conduction in vivo than groups A and C, indicating that the porous n-HA/PA66 matrices with a mean pore size of 375 ± 132.2 μm and porosity 77 ± 2.9% have better cell biocompatibility and bone conduction.

The improved bioactive n-HA/PA66 cage versus the PEEK cage in anterior cervical fusion: results from a 6-year follow-up and a case-matched study

“…The bone graft volumes in both cages were similar and sufficiently large to be filled with bone fragments during surgery, and they had enough bone mass for osteogenesis. On the other hand, the pore size and porosity played crucial roles in the scaffold architecture and cell proliferation, differentiation and bone in-growth [24]. In the goat C3/4 partial discectomy and fusion model, the mean CT fusion scores of the porous n-HA/PA66 group were significantly higher than those of the dense strut group (porous group vs. dense group: 15.33 ± 2.55 and 10.67 ± 2.55 at 12 weeks, 23.60 ± 3.57 and 16.60 ± 4.67 at 24 weeks, P < 0.05).…”

“…The improved n-HA/PA66 cage is still dense, which could limit its biological activity. To overcome these drawbacks, a novel porous n-HA/PA66 composite has been developed in recent years [24][25][26][27]. More effort Cage subsidence in ACDF can be influenced by many factors, including end plate preparation, postoperative cervical motion, cage design and material properties, implantation of the anterior cervical plate, and bone mineral density or age [28][29][30][31].…”

The Improved Bioactive n-HA/PA66 Cage Versus the PEEK Cage in Anterior Cervical Fusion: Results from a 6-year Follow-up and a Case-matched Study

“…The bone graft volumes in both cages were similar and su ciently large to be lled with bone fragments during surgery, and they had enough bone mass for osteogenesis. On the other hand, the pore size and porosity played crucial roles in the scaffold architecture and cell proliferation, differentiation and bone in-growth [20] . In the goat C3/4 partial discectomy and fusion model, the mean CT fusion scores of the porous n-HA/PA66 group were signi cantly higher than those of the dense strut group (porous group vs. dense group: 15.33 ± 2.55 and 10.67 ± 2.55 at 12 weeks, 23.60 ± 3.57 and 16.60 ± 4.67 at 24 weeks, P < 0.05).…”

“…The improved n-HA/PA66 cage is still dense, which could limit its biological activity. To overcome these drawbacks, a novel porous n-HA/PA66 composite has been developed in recent years [20][21][22][23] . More effort is necessary to translate it into clinical use, which might enhance radiological and clinical results.…”

Reconstruction of Load-Bearing Segmental Bone Defects Using Carbonate Apatite Honeycomb Blocks

“…Generally, synthetic bone blocks are used to clinically treat the defect in osteotomy surgeries of loading limbs. − Therefore, the effects of the pore characteristics in blocks on mechanical strength, osteoconductivity, and bioresorbability should be evaluated by implanting blocks in load-bearing segmental defects. However, previous studies have investigated the effect of the pore characteristics in synthetic bone blocks on bone reconstruction using nonload-bearing bone defects. − Furthermore, while these studies did not evaluate the mechanical strength of the blocks, they did investigate osteoconductivity and bioresorbability. Therefore, the optimal pore characteristics for the reconstruction of load-bearing segmental defects remain unclear.…”