Structure and performance of injectable strontium-contained collagen calcium phosphate cement

Dongping YE; Ziqiang ZHOU; Weiguo LIANG

ABSTRACT

BACKGROUND:

Orthopedic academics are committed to the modification of calcium phosphate cement (CPC) by adding different additives, including the promotion of curing agents, plasticizers, anti-water blood solvent, porogen, enhancer, or biological activity substance or drug compound to the CPC in order to enhance its physical and chemical and biological properties which is a research hotspot in the field.

OBJECTIVE:

To investigate the physical and chemical characteristics of a biodegradable injectable CPC. DESIGN, TIME AND

SETTING:

Duplicated testing study was performed at the National Key Laboratory, College of Materials, South China University of Technology from December 2008 to May 2009. MATERIALS Calcium phosphate with partial crystallization and strontium phosphate and calcium hydrogen phosphate dehydrate with partial crystallization were added with modified starch and type I collagen to prepare a new type of self-injectable CPC.

METHODS:

CPC phase was analyzed using X'Pert Pro X-ray diffractometer; CPC morphology was observed using HITA2 -CHIH-800 transmission/scanning electron microscope; setting-up time was tested using Vicat apparatus according to A S TM C190203 standard; compressive strength was measured using Instron 5567 omnipotent electron apparatus; syringeability was detected using syringe apparatus with 1.6 mm of inside diameter; collapsibility was tested using soaking-shaking quantitative materials. MAIN OUTCOME

MEASURES:

Phase component and microstructure of CPC products, setting-up time, syringeability, compressive strength, and collapsibility.

RESULTS:

The material coul be injected with an excellent performance, and the modified starch significantly improved the resistance of bone cement collapsibility. As the bone cement liquid-solid ratio increased, the compressive strength of cement decreased. When the bone cement liquid-solid ratio was 0.3, the compressive strength for cement was (48.0±2.3) MPa when the bone cement liquid-solid ratio was 0.6, the compressive strength of bone cement reduced to (21,0±2.5) MPa. Hydration productof cement-like bone hydroxyapatite crystallization also could be seen from the X-ray diffraction, due to the hydration of-cement was not complete, a baseline level of volatile explained fully hydrated conditions, suggesting that the bone cement could farther improve the compression strength.

CONCLUSION:

Developed an injectable strontium-contained collagen CPC is coincidence with the biomechanical strength of the human body and meets the requirements of the operation conditions.