Growth behavior of rat bone marrow cells on RF magnetron sputtered hydroxyapatite and dicalcium pyrophosphate coatings

Abstract

The aim of this study was to evaluate the osteogenic properties of magnetron sputtered dicalcium pyrophaosphate (DCPP) and hydroxylapatite (HA) coatings. Therefore, DCPP and HA coatings were deposited on grit-blasted titanium discs. The substrates were used as-prepared or received an additional heat treatment which changed the amorphous coating structure to a crystalline structure. Subsequently, rat bone marrow stromal cells were cultured for 1-24 days on the various substrates. DNA and alkaline phosphatase activity was determined after 1, 3, 5, 8, and 12 days of incubation. Osteocalcin expression was evaluated after 8, 12, 16, and 24 days of incubation. Scanning electron microscopical analysis of cell morphology and coating characteristics was done after 8 and 16 days of incubation. All assays were done in duplicate and in each assay all specimens were present in fourfold. Results demonstrated that the cells did not proliferate and differentiate on all amorphous coatings. SEM revealed that the amorphous coatings showed significant dissolution. On the crystalline DCPP and HA coatings an increase in DNA and alkaline phosphatase activity was seen starting at day 8 of incubation. Osteocalcin expression on the crystalline coatings started to increase at day 16 of incubation. SEM showed that the growth and differentiation of the cells was associated with extensive collagen fiber formation and surface mineralization in the form of globular accretions. Further, statistical testing revealed that proliferation and differentiation of the rat bone marrow stromal cells started significantly earlier on the crystalline HA coatings than that on the crystalline DCPP coatings. These results demonstrate that the rat bone marrow stromal cells proliferated and differentiated only on crystalline magnetron sputtered DCPP as well as HA coatings, which warrants the further in vivo analysis of the bone healing supporting properties of these coatings.

Calcium orthophosphate coatings, films and layers

“…A greater percent of bone contact lengths were detected for calcium orthophosphate-coated Ti implants compared with control Ti implants 3 and 12 weeks after implant placement (Ong et al 2002). Similar results were obtained in other studies (Dalton and Cook 1995; Nguyen et al 2004; Yan et al 2006). …”

Calcium orthophosphate deposits: Preparation, properties and biomedical applications

“…A greater percent of bone contact lengths was detected for the CaPO 4 -coated Ti implants compared to the uncoated controls 3 and 12 weeks after the implant placement [844]. Similar results were obtained in other studies [845][846][847]. Obviously, a better wettability of CaPO 4 -coated substrates, if compared to the uncoated controls (Fig.…”

Synthesis of UV‐curable/alkali‐soluble dispersants used for black photoresist with a high loading of carbon black

“…Several methods have been used to produced HA micropatterns, such as sputtering,13, 14 biomineralization,15, 16 and electrophoretic deposition 17. Sputtering technique is noteworthy since it can seamlessly combine with microfabrication process and produce uniform HA thin films on micro‐machined surfaces with good repeatability 13, 14, 18…”