Preparation and biological evaluation of hydroxyapatite-coated nickel-free high-nitrogen stainless steel

Abstract

Calcium phosphate was formed on nickel-free high-nitrogen stainless steel (HNS) by chemical solution deposition. The calcium phosphate deposition was enhanced by glutamic acid covalently immobilized on the surface of HNS with trisuccinimidyl citrate as a linker. X-ray diffraction patterns and Fourier transform infrared spectra showed that the material deposited on glutamic acid-immobilized HNS within 24 h was low-crystallinity calcium-deficient carbonate-containing hydroxyapatite (HAp). The biological activity of the resulting HAp-coated HNS was investigated by using a human osteoblast-like MG-63 cell culture. The HAp-coated HNS stimulated the alkaline-phosphate activity of the MG-63 culture after 7 days. Therefore, HAp-coated HNS is suitable for orthopedic devices and soft tissue adhesion materials.

Investigation of microbiologically influenced corrosion of high nitrogen nickel-free stainless steel by Pseudomonas aeruginosa

“…The corresponding spectra of the biotic coupon were curve-fitted with two dominant peaks for CrN (BE at 396.8 eV) and NH3 (BE at 398.6 eV). NH3, NH4 + and CrN have been reported by others to be present in biofilms and passivation films on coupon surfaces [47][48][49]. The Cr 2p peaks were curve-fitted as Cr2O3 and Cr(OH)3 for the abiotic coupon, and as Cr2N, Cr2O3 and Cr(OH)3 for the biotic coupon respectively [44,[50][51][52][53][54][55], which were all shown in Table 8.…”

“…The nitrogen addition smoothens of surface, promotes the formation of a passivation film and improves their pitting corrosion resistance to corrosive chemicals [48,49]. The previous reports proved that HNS with high concentrate of nitrogen possesses better corrosion resistance compared with traditional stainless steels (e.g.…”