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Polylactic acid - calcium phosphates composites

Marina Sokolova ,  Vita Zalite ,  Janis Locs ,  Liga Berzina-Cimdina 

Riga Biomaterials Innovation and Development Centre, Riga LV-1007, Latvia


Bioactive ceramics such as hydroxyapatite (HAp) and tricalcium phosphate (TCP) are one of the most popular implant materials in the reconstructive surgery to repair damaged hard tissues. Calcium phosphates (CaP) have excellent biomaterial properties due to their similarity to the inorganic component of the bone matrix. However, CaP clinical application is restricted due to their inherent brittleness and poor shape ability. To capitalize the advantage of CaP and overcome some drawbacks, CaP is combined with polylactic acid to generate highly porous biocomposite materials. Polylactic acid (PLA) has good mechanical properties and low toxicity.
CaP – PLA composites have received a great deal of interest in orthopedic and dental applications, which is attributed to their good osteoconductivity, biodegradability and high mechanical strength.
In this study CaP powder was prepared by wet chemical precipitation method from calcium hydroxide suspension and ortophosphoric acid solution. Multiple factors like suspension temperature, pH, acid addition rate and mixing determine phase composition of the product. Lower temperatures and acidic pH values promote formation of β-TCP phase, but slightly alkaline pH and higher temperatures promote formation of HAp phase. It is possible to obtain calcium phosphate product with diverse phase composition, by varying these parameters
There is a problem with homogenization of CaP with the PLA due to different chemical characteristics of hydrophilic CaP and hydrophobic PLA. Organic solvents normally used for dissolving PLA could not be used to effectively disperse the CaP powder. The aim of this study was to resolve homogenization and intermixing problem raised on the ceramic – polymer biomedical composite system.
Fourier-transform infrared spectroscopy (FT-IR) is used to determine the characteristic functional groups in the sintered calcium phosphate samples. X−ray diffractometry (XRD) is used to analyze phase composition of obtained bioceramics samples. Scanning electron microscopy (SEM) is used to characterize the morphology of the obtained samples.


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Presentation: Poster at Nano-Biotechnologia PL, by Marina Sokolova
See On-line Journal of Nano-Biotechnologia PL

Submitted: 2012-06-30 11:24
Revised:   2012-06-30 11:24