In Vitro Osteogenesis Stimulation via Nano-Hydroxyapatite/Carbon Nanotube Thin Films on Biomedical Stainless Steel

Abstract

We evaluated the electrophoretic deposition of nanohydroxyapatite/superhydrop hilic multiwalled carbon nanotube composites (nHAp/MWCNT) onto stainless steel biomedical alloys for applications in bone tissue engineering. First, nHAp/MWCNT composites were dispersed into 0.042 mol·L−1 of Ca(NO3)2·4H2O + 0.025 mol·L−1 NH4H2PO4 electrolytes (pH = 4.8) at two different concentrations. Next, a voltage of −2 V was applied using 316L stainless steel as a working electrode (0.27 cm2), a high-purity platinum coil wire was used as the auxiliary electrode, and an Ag/AgCl (3 M) electrode was used as the reference electrode. The nHAp/MWCNT composites were characterized by transmission electron microscopy. The deposited nHAp and nHAp/MWCNT films were characterized by profilometry, scanning electron microscopy, X-ray diffractometry and Raman spectroscopy. Human osteoblast cells were cultivated with the different materials and in vitro cytotoxicity was evaluated using lactate dehydrogenase (LDH) assay. The osteogenesis process was evaluated by mRNA levels of the three genes that are directly related to bone repair: Alkaline Phosphatase, Osteopontin and Osteocalcin. We showed that rough, crystalline apatite thin films containing phases of nHAp were successfully deposited onto 316L stainless steel alloys. Also, we noticed that nHAp/MWCNT thin films deposited onto 316L stainless steel alloys upregulated the expression of important genes related to bone mineralization and maturation. Our results strongly support the possibility of this new alternative to modify the surface of metallic biomedical alloys to promote bone tissue regeneration.

3D printed hydroxyapatite promotes congruent bone ingrowth in rat load bearing defects

“…Recent studies have elucidated that HAP, when used in the form of a nanocomposite, augmented the expression of osteogenic proteins alkaline phosphate (ALP), osteocalcin (OC), and osteopontin (OPN), along with enhanced calcium deposition, which is involved in osteogenic differentiation and mineralization [26]. This is in accordance with the findings of Martinelli et al [27]. They reported increased OC and OPN activity while using nanohydroxyapatite carbon composites; increased ALP activity was observed, which showed the potential of the nanohydroxyapatite to enhance biomineralization.…”

Tubular nanomaterials for bone tissue engineering

“…nHA/MWCNT composites showed no cytotoxicity against MG-63 human osteoblast cells and upregulated genes related to bone maturation and mineralization. 150 The composite scaffolds of chitosan/gelatin/nanohydroxyapatite/multiwalled carbon nanotube (CS/Gel/nHA/MWCNT) provided adequate space for cell adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 cells. An increasing MWCNT content led to an increase in hydrophobicity and a decrease in degradation rate whilst enhancing the mechanical strength of the scaffold.…”

Multi-endpoint assessments for in vitro nano-bio interactions and uptake of biogenic phosphorus nanomaterials using HEK293 cells

“…13 This had relevance when nHAPs were to be explored for biomedical purposes such as bone grafting and tissue engineering. For such applications, majorly surface-functionalized nHAP and its composites with other materials such as chitosan, 14 caprolactone, 15 carbon nanotube, 16 gelatin, 17 and elements like europium, 18 yttrium 19 and strontium 19 were used. Further, for nHAPs without any co-substitutions or modifications, there are some reports showing the toxicity of nHAP to BEAS-2B (lung cell line), 20 RAW264.7 (mouse macrophage), 21 catfish B (3B11) and T (28s 3) immune cells, 22 L929 (murine fibroblasts), 23 and primary rat osteoblasts.…”