Do novel cement-type biomaterials reveal ion reactivity that affects cell viability in vitro?

Abstract

Calcium phosphate bioceramics have been studied as bone filler materials for years and have become a component of many commercial products. It is widely known that surface-reactive biomaterials may cause changes in the concentration of crucial ions in the surrounding environment, thereby affecting cell metabolism and viability. The aim of this study was to produce five cement-type biomaterials and characterize their phase composition using X-ray diffraction method, and porosity and pore size distribution using mercury intrusion porosimeter. We then evaluated ion interactions of the novel biomaterials with the surrounding environment (culture medium). A commercially available bone substitute, HydroSet™ (Stryker®), was used as a reference. MTT and NRU cytotoxicity tests were performed to assess the effect of changes in the concentration of crucial ions (calcium, magnesium, phosphate) on osteoblast metabolism and viability in vitro. Our study clearly indicated that various biomaterials demonstrated different ion reactivity and consequently may cause changes in ion concentration in the local environment. Critically low or high values of calcium, magnesium, and phosphate concentrations in the medium exerted cytotoxic effects on the cultured cells. Moreover, we discovered that the chemical composition of the culture medium had a substantial influence on ion interactions with biomaterials.

Osteogenic cell response to 3-D hydroxyapatite scaffolds developed via replication of natural marine sponges

“…Magnesium has been reported to enhance osteoblast adhesion, increase angiogenesis in porous structures [ 24 ], increase bone formation [ 25 ] and increase bioresorption [ 26 , 27 ]. Crucially, in vitro, several papers have reported that high and low concentrations of Mg are inhibitory to cell proliferation and/or cytotoxic but optimal concentrations can enhance osteoblast proliferation and mineralization [ 28 , 29 ]. The findings of the current study support this but would suggest that this initial increase is transitory.…”

Do Ca2+-adsorbing ceramics reduce the release of calcium ions from gypsum-based biomaterials?

“…Evaluation of ionic reactivity was performed based on a previously described procedure [2]. Briefly, granules sintered at various temperatures (90°C, 400°C, 800°C and 1150°C) were placed on a 24-well plate (200 mg per well) and sterilized using the ethylene dioxide method (1 h at 55°C with a subsequent degassation for 20 h).…”

“…Despite many advantages, the relatively rapid rate of in vivo gypsum resorption may disturb the rate of appropriate, gradual replacement of the biomaterial by the newly formed bone. Furthermore, due to the rapid resorption of gypsum and gypsum-based composites, the resulting calcium-rich fluid is relatively toxic for human osteoblasts [1,2]. The presence of OsteoSet® pellets (calcium sulfate bone void filler) caused a decrease in osteogenic cell proliferation [3].…”

“…Physiological changes in extracellular calcium concentrations may also affect osteoblast function [6]. It is therefore not surprising that the elevated Ca +2 concentrations in the fluids incubated with gypsum-based implants, highly exceeding those optimal for osteoblast cells, dramatically reduce their metabolism and viability [2].…”

How calcite and modified hydroxyapatite influence physicochemical properties and cytocompatibility of alpha-TCP based bone cements

“…The cellular response to CPCs is linked to their phase composition [22]. The effect of chemical stability and resorbability of biomaterials, including ion release, on the cellular response was confirmed inter alia by Malafaya and Reis [23] and Przekora et al [10]. …”