Biological responses of brushite-forming Zn- and ZnSr- substituted beta-tricalcium phosphate bone cements

Abstract

The core aim of this study was to investigate zinc (Zn)and zinc and strontium (ZnSr)-containing brushite-forming β-tricalcium phosphate (TCP) cements for their effects on proliferation and differentiation of osteoblastic-like cells (MC3T3-E1 cell line) as well as for their in vivo behaviour in trabecular bone cylindrical defects in a pilot study. In vitro proliferation and maturation responses of MC3T3-E1 osteoblastic-like cells to bone cements were studied at the cellular and molecular levels. The Zn-and Sr-containing brushite cements were found to stimulate pre-osteoblastic proliferation and osteoblastic maturation. Indeed, MC3T3-E1 cells exposed to the powdered cements had increased proliferative rates and higher adhesiveness capacity, in comparison to control cells. Furthermore, they exhibited higher alkaline phosphatase (ALP) activity and increased Type-I collagen secretion and fibre deposition into the extracellular matrix. Proliferative and collagen deposition properties were more evident for cells grown in cements doped with Sr. The in vivo osteoconductive properties of the ZnCPC and ZnSrCPC cements were also pursued. Histological and histomorphometric analyses were performed at 1 and 2 months after implantation, using carbonated apatite cement (Norian SRS ® ) as control. There was no evidence of cement-induced adverse foreign body reactions, and furthermore ZnCPC and ZnSrCPC cements revealed better in vivo performance in comparison to the control apatite cement. Additionally, the presence of both zinc and strontium resulted in the highest rate of new bone formation. These novel results indicate that the investigated ZnCPC and ZnSrCPC cements are both biocompatible and osteoconductive, being good candidate materials to use as bone substitutes. a Both authors contributed equally to this work 163 www.ecmjournal.org S Pina et al. Brushite-forming bone cements

Biofunctional Ionic-Doped Calcium Phosphates: Silk Fibroin Composites for Bone Tissue Engineering Scaffolding

“…SF/TCP and SF/ ionic-doped TCP scaffolds exhibited a slower degradation rate compared with the SF scaffolds. This may be related to the pore structure and the molecular weight level of SF, but is mainly due to the crystalline structure and the presence of ionic-dopants (Sr, Zn, and Mn) on the scaffolds, which are known to contribute in the bone development process [Cao and Wang, 2009;Pina et al, 2010aPina et al, , 2010bRoy et al, 2013].…”

“…There has been significant interest in Bombyx mori as a source of silk fibroin (SF) on account of its remarkable elasticity, mechanical strength, toughness, biocompatibility, and biodegradability with controllable degradation rates [Vepari and Kaplan, 2007;Li et al, 2013]. CaPs have been shown to exhibit remarkable bioactivity, biocompatibility, bioresorbability, and excellent osteoconductive properties [Pina et al, 2010a[Pina et al, , 2010b. β-Tricalcium phosphate (β-TCP) is greatly biocompatible and resorbable, thereby instigating the replacement of the implants by the tissues.…”

Insights on the properties of levofloxacin-adsorbed Sr- and Mg-doped calcium phosphate powders

“…Doping HA with Mg and Sr ions is likely to further enhance the physico-chemical and especially the biological properties of the resulting materials [23][24][25]. While pure HA phase was obtained for the stoichiometric composition heat treated for 1 h at 800°C, doping with Mg and Sr ions resulted in the formation of b-TCP as secondary phase, which is more abundant in [Mg-HA], Fig.…”

“…HA deserved a particular attention because of its chemical and structural & Catarina F. Marques acmarques@ua.pt similarities with the inorganic phase of human bone and its biocompatibility, osteoconductive and osteophilic nature [17,18]. Moreover, the crystalline lattice of HA is able to easily incorporate foreign substituting ions that enhance osteointegration and mechanical properties of the grafts [19][20][21][22][23]. Magnesium (Mg 2? )…”

“…Strontium (Sr 2? ) is another interesting doping ion since it increases osteoclast apoptosis and enhances preosteoblastic cell proliferation and collagen synthesis, with consequent depression in bone resorption and maintained bone formation [23].…”