CALCIUM PHOSPHATE CERAMICS IN DRUG DELIVERY AND BONE TISSUE ENGINEERING

摘要

In the present study we have used calcium phosphate (CaP) ceramics in drug delivery and bone tissue engineering applications. For drug delivery, pH sensitive multifunctional CaP nano carriers have been synthesized. Alendronate, a bisphonate drug, is used to study the drug release at different pH from CaP/AD composites. A CaP/AD/RDB (RDB: Rhodamine B dye) composite system is used to examine the sensing of drug release by fluorescence measurement of RDB dye. Average dimension of the synthesized CaP, CaP/AD and CaP/AD/RDB nanoparticles are 55nm x 136 nm, 20 nm x 44 nm and 20 nm x 44 nm, respectively. High AD release is observed at pH 5.0 similar to cellular microenvironment compared to pH 7.5 similar to physiological environment. For tissue engineering application,, commercially pure β-tricalcium phosphate (β-TCP) is used for 3 dimensional printing (3DP). CaP scaffolds with interconnected macropores between 500 μm and 1000 μm are fabricated by 3DP. Resulting scaffolds are sintered in a conventional electric furnace at 1250 °C for 2 h and in a microwave furnace at 1250 °C for 1 h. Irrespective of the macropore size, microwave sintering resulted in high compressive strength compared to conventional sintering. A maximum compressive strength of 10.95±1.28 MPa is achieved for 500 μm interconnected macroporous scaffolds by microwave sintering, while a compressive strength of 6.62±0.67 MPa is achieved by conventional sintering. An increase in compressive strength is observed with decreasing macropore size for both conventional and microwave sintering.