Preparation, Characterization, In Vitro Bioactivity, and Cellular Responses to a Polyetheretherketone Bioactive Composite Containing Nanocalcium Silicate for Bone Repair

Abstract

In this study, a nanocalcium silicate (n-CS)/polyetheretherketone (PEEK) bioactive composite was prepared using a process of compounding and injection-molding. The mechanical properties, hydrophilicity, and in vitro bioactivity of the composite, as well as the cellular responses of MC3T3-E1 cells (attachment, proliferation, spreading, and differentiation) to the composite, were investigated. The results showed that the mechanical properties and hydrophilicity of the composites were significantly improved by the addition of n-CS to PEEK. In addition, an apatite-layer formed on the composite surface after immersion in simulated body fluid (SBF) for 7 days. In cell culture tests, the results revealed that the n-CS/PEEK composite significantly promoted cell attachment, proliferation, and spreading compared with PEEK or ultrahigh molecular weight polyethylene (UHMWPE). Moreover, cells grown on the composite exhibited higher alkaline phosphatase (ALP) activity, more calcium nodule-formation, and higher expression levels of osteogenic differentiation-related genes than cells grown on PEEK or UHMWPE. These results indicated that the incorporation of n-CS to PEEK could greatly improve the bioactivity and biocompatibility of the composite. Thus, the n-CS/PEEK composite may be a promising bone repair material for use in orthopedic clinics.

Osseointegration of nanohydroxyapatite- or nano-calcium silicate-incorporated polyetheretherketone bioactive composites in vivo

“…Our previous results 25,26 indicated that elastic modulus and compressive strength of the composite increased with increasing n-HA or n-CS content from 0 to 40 wt%, while the highest n-HA or n-CS content (60 wt%) yielded a lower elastic modulus and compressive strength, so the concentration of n-HA or n-CS in PEEK composite in this study was determined as 40 wt%. The 40 wt% n-HA/PEEK and 40 wt% n-CS/PEEK composites were fabricated using a compounding and injectionmolding technique according to our previously reported procedure, 25,26 and the pure PEEK sample was prepared using an injection-molding technique.…”

“…In addition, CS offers improved bioactivity compared with that of calcium phosphate materials. 18,19 In our previous study, 25 an apatite layer was formed on the n-CS/PEEK composite, and the entire surface of this specimen was nearly covered with a thick and compact apatite layer after immersion for 28 days. We predicted that apatite would form on the surface of n-CS/ PEEK in the early implantation period, and then, the bone matrix would integrate with the apatite.…”

“…The 40 wt% n-HA/PEEK and 40 wt% n-CS/PEEK composites were fabricated using a compounding and injectionmolding technique according to our previously reported procedure, 25,26 and the pure PEEK sample was prepared using an injection-molding technique. Briefly, the PEEK and n-HA/n-CS powders were compounded in a high-speed ball mill (QM-3B, T-Bota Scietech Instruments & Equipment Ltd., Nanjing, People's Republic of China) at a mixing speed of 500 rpm for 1 hour; the mixtures were then dried at 150°C for 24 hours; and the samples were produced using an injection-molding machine (Battenfeld BA-300/050CD, Awans, Belgium) at an injecting and molding temperature of 380°C.…”

“…23,24 In previous studies, 25,26 our research group used a compounding and injection-molding technique to separately incorporate nanohydroxyapatite (n-HA) and nano-calcium silicate (n-CS) into PEEK to prepare n-HA/PEEK and n-CS/PEEK composites, respectively. The optimal incorporating ratio for both n-HA and n-CS was 40 weight% (wt%), and both n-HA/PEEK and n-CS/ PEEK exhibited good bioactivity, which was confirmed by a simulated body fluid soaking test and in vitro cell tests.…”

Effects of magnesium silicate on the mechanical properties, biocompatibility, bioactivity, degradability, and osteogenesis of poly(butylene succinate)-based composite scaffolds for bone repair

“…The cell proliferation was expressed as relative proliferation rates, in which the modified ODs at day 3 and 5 were normalized to those at day 1 for each group. 20 2.5.3 Cell morphology. Cell morphology was visualized by detecting the filamentous actin of the cytoskeleton of MC3T3-E1 cells into scaffolds.…”