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Effect of microstructure characteristics on tetracalcium phosphate–nanomonetite cement in
vitro cytotoxicity
This content has been downloaded from IOPscience. Please scroll down to see the full text. 2015 Biomed. Mater. 10 025006 (http://iopscience.iop.org/1748-605X/10/2/025006) View the table of contents for this issue, or go to the journal homepage for more
Download details: IP Address: 169.230.243.252 This content was downloaded on 31/03/2015 at 06:04
Please note that terms and conditions apply.
Biomed. Mater. 10 (2015) 025006
doi:10.1088/1748-6041/10/2/025006
Paper
received
9 December 2014
Effect of microstructure characteristics on tetracalcium phosphate–nanomonetite cement in vitro cytotoxicity
accep ted for publication
24 February 2015 published
25 March 2015
Lubomir Medvecky, Maria Giretova, Radoslava Stulajterova and Monika Kasiarova Department of Electroceramics, Institute of Materials Research of SAS, Watsonova 47, 040 01 Kosice, Slovakia E-mail: [email protected] Keywords: calcium phosphate cement, tetracalcium phosphate, in vitro cytotoxicity, osteoblasts, microstructure
Abstract MC3T3E1 murine pre-osteoblastic cells were used to evaluate the cytotoxicity of tetracalcium phosphate (TTCP)–nanomonetite (DCPA) cement. The starting cement powder mixture was prepared by the in situ reaction between TTCP and a diluted solution of orthophosphoric acid in a planetary ball mill. The cements in the form of pressed cement powder mixture discs differ from each other by the method of pre-treatment and degree of the transformation of cement components in phosphate-buffered saline (PBS). For the evaluation of TTCP–DCPA cement to be non-cytotoxic, it was sufficient to apply the short-time soaking in PBS solution, regardless of whether the cement components were completely transformed or not. If the texture motif and hydroxyapatite particle morphology were properly developed during the initial stage of hardening, the cement cytotoxicity or osteoblast proliferation were insignificantly influenced by the soaking time or the texture stability during cell cultivation, but the lattice ordering enhanced cell proliferation. Results showed that the surface texture and the hydroxyapatite particle morphology are crucial for in vitro cement cytotoxicity evaluation.
1. Introduction Calcium phosphate cements (CPCs) belong to a very important class of biomaterials because of their excellent biocompatibility and osteoconductivity, which are properties pre-determining their possible utilization in the human body for bone repair and substitution [1–5]. One of the most studied CPCs, which is composed of a basic component (tetracalcium phosphate (TTCP)) and a more acidic component (e.g. brushite or monetite), is characterized by self-hardening during acido-basic reaction with calcium-deficient hydroxyapatite (CDHA) as a final product after the addition of hardening liquid [6]. The CPCs have good bioactivity, noncytotoxicity, osteoconductivity and they can be replaced by new bone because of their bioresorbable properties [7]. The properties of cements are influenced by various parameters such as the particle size of starting cement precursors [8, 9], the TTCP/DCPA mole ratio [10], the powder to liquid ratio (P/L) in cement paste [11], and the chemical nature of hardening liquids and additives [12]. TTCP cements showed better antimicrobial activity than the calcium hydroxide ones [13] and no significant influence on cell proliferation with the © 2015 IOP Publishing Ltd
increase in alkaline phosphatase (ALP) activity and osteogenesis promotion was verified [14]. The rise in Ca2+ ion and the decrease of PO34− concentrations were measured in α-modification Minimum Essential Medium Eagle (MEM) [15] and high pH values were reached during TTCP cement hardening because of TTCP hydrolysis in the first stage of hardening [16]. The verification of the osteoblast cytotoxicity of fresh CPC paste supported opinion that this behavior was caused by the increase of both the local ion concentration and pH during the transformation of cement paste [17]. It was demonstrated that 2–4 mM concentration of Ca2+ ions is favorable for osteoblast proliferation and cell differentiation was promoted at even higher calcium concentration but does not exceed 10 mM [18]. On the other hand, the activated osteoblast apoptosis by phosphate ions above a concentration of 5 mM was confirmed [19]. Besides the above-reported effects of the ion concentration, a significant effect of cement particle size on osteoblast proliferation with a strong inhibition by the particles
Search
Collections
Journals
About
Contact us
My IOPscience
Effect of microstructure characteristics on tetracalcium phosphate–nanomonetite cement in
vitro cytotoxicity
This content has been downloaded from IOPscience. Please scroll down to see the full text. 2015 Biomed. Mater. 10 025006 (http://iopscience.iop.org/1748-605X/10/2/025006) View the table of contents for this issue, or go to the journal homepage for more
Download details: IP Address: 169.230.243.252 This content was downloaded on 31/03/2015 at 06:04
Please note that terms and conditions apply.
Biomed. Mater. 10 (2015) 025006
doi:10.1088/1748-6041/10/2/025006
Paper
received
9 December 2014
Effect of microstructure characteristics on tetracalcium phosphate–nanomonetite cement in vitro cytotoxicity
accep ted for publication
24 February 2015 published
25 March 2015
Lubomir Medvecky, Maria Giretova, Radoslava Stulajterova and Monika Kasiarova Department of Electroceramics, Institute of Materials Research of SAS, Watsonova 47, 040 01 Kosice, Slovakia E-mail: [email protected] Keywords: calcium phosphate cement, tetracalcium phosphate, in vitro cytotoxicity, osteoblasts, microstructure
Abstract MC3T3E1 murine pre-osteoblastic cells were used to evaluate the cytotoxicity of tetracalcium phosphate (TTCP)–nanomonetite (DCPA) cement. The starting cement powder mixture was prepared by the in situ reaction between TTCP and a diluted solution of orthophosphoric acid in a planetary ball mill. The cements in the form of pressed cement powder mixture discs differ from each other by the method of pre-treatment and degree of the transformation of cement components in phosphate-buffered saline (PBS). For the evaluation of TTCP–DCPA cement to be non-cytotoxic, it was sufficient to apply the short-time soaking in PBS solution, regardless of whether the cement components were completely transformed or not. If the texture motif and hydroxyapatite particle morphology were properly developed during the initial stage of hardening, the cement cytotoxicity or osteoblast proliferation were insignificantly influenced by the soaking time or the texture stability during cell cultivation, but the lattice ordering enhanced cell proliferation. Results showed that the surface texture and the hydroxyapatite particle morphology are crucial for in vitro cement cytotoxicity evaluation.
1. Introduction Calcium phosphate cements (CPCs) belong to a very important class of biomaterials because of their excellent biocompatibility and osteoconductivity, which are properties pre-determining their possible utilization in the human body for bone repair and substitution [1–5]. One of the most studied CPCs, which is composed of a basic component (tetracalcium phosphate (TTCP)) and a more acidic component (e.g. brushite or monetite), is characterized by self-hardening during acido-basic reaction with calcium-deficient hydroxyapatite (CDHA) as a final product after the addition of hardening liquid [6]. The CPCs have good bioactivity, noncytotoxicity, osteoconductivity and they can be replaced by new bone because of their bioresorbable properties [7]. The properties of cements are influenced by various parameters such as the particle size of starting cement precursors [8, 9], the TTCP/DCPA mole ratio [10], the powder to liquid ratio (P/L) in cement paste [11], and the chemical nature of hardening liquids and additives [12]. TTCP cements showed better antimicrobial activity than the calcium hydroxide ones [13] and no significant influence on cell proliferation with the © 2015 IOP Publishing Ltd
increase in alkaline phosphatase (ALP) activity and osteogenesis promotion was verified [14]. The rise in Ca2+ ion and the decrease of PO34− concentrations were measured in α-modification Minimum Essential Medium Eagle (MEM) [15] and high pH values were reached during TTCP cement hardening because of TTCP hydrolysis in the first stage of hardening [16]. The verification of the osteoblast cytotoxicity of fresh CPC paste supported opinion that this behavior was caused by the increase of both the local ion concentration and pH during the transformation of cement paste [17]. It was demonstrated that 2–4 mM concentration of Ca2+ ions is favorable for osteoblast proliferation and cell differentiation was promoted at even higher calcium concentration but does not exceed 10 mM [18]. On the other hand, the activated osteoblast apoptosis by phosphate ions above a concentration of 5 mM was confirmed [19]. Besides the above-reported effects of the ion concentration, a significant effect of cement particle size on osteoblast proliferation with a strong inhibition by the particles
