Indiana University-Purdue University Indianapolis (IUPUI) / Dicalcium phosphate dihydrate (DCPD) cements have been used for bone repair due to its excellent biocompatibility and resorbability. However, DCPD cements are typically weak and brittle. To overcome these limitations, the sodium citrate used as a setting regulator and the coating of poly-L-lactide acid (PLLA) technique have been proposed in this study. The first purpose of this thesis is to develop composite PLLA/DCPD scaffolds with enhanced toughness by PLLA coating. The second purpose is to
examine the biocompatibility of the scaffolds. The final purpose is to investigate the degradation behaviors of DCPD and PLLA/DCPD scaffolds. In this experiment, DCPD cements were synthesized from monocalcium phosphate monohydrate (MCPM) and 𝛽-tricalcium phosphate (𝛽 –TCP) by using deionized water and sodium citrate as liquid components. The samples were prepared with powder to liquid ratio (P/L) at 1.00, 1.25 and 1.50. To fabricate the PLLA/DCPD composite samples, DCPD samples were coated with 5 % PLLA. The samples were characterized mechanical properties, such as porosity, diametral tensile strength, and fracture energy. The mechanical properties of DCPD scaffolds with and without PLLA coating after the in vitro static degradation (day 1, week1, 4, and 6) and in vitro dynamic degradation (day 1, week 1, 2, 4, 6, and 8) were investigated by measuring their weight loss, fracture energy, and pH of phosphate buffer
solution. In addition, the dog bone marrow stromal stem cells (dBMSCs) adhesion on
DCPD and PLLA/DCPD composite samples were examined by scanning electron
microscopy. The cell proliferation and differentiation in the medium conditioned with
DCPD and PLLA/DCPD composite samples were studied by XTT (2,3-Bis(2-methoxy-4-
nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide inner salt), and alkaline phosphatase (ALP) assay, respectively. The addition of sodium citrate and PLLA coating played a
crucial role in improving the mechanical properties of the samples by increasing the
diametral tensile strength from 0.50 ± 0.15 MPa to 2.70 ± 0.54 MPa and increasing the
fracture energy from 0.76 ± 0.18 N-mm to 12.67 ± 4.97 N-mm. The DCPD and
PLLA/DCPD composite samples were compatible with dBMSCs and the cells were able
to proliferate and differentiate in the conditioned medium. The degradation rate of DCPD
and PLLA/DCPD samples were not significant different (p > 0.05). However, the DCPD
and PLLA/DCPD composite samples those used sodium citrate as a liquid component
was found to degrade faster than the groups that use deionized water as liquid component
| Identifer | oai:union.ndltd.org:IUPUI/oai:scholarworks.iupui.edu:1805/4448 |
| Date | 21 May 2014 |
| Creators | Tanataweethum, Nida |
| Contributors | Chu, Tien-Min Gabriel, Lin, Chien-Chi, Bottino, Marco C. |
| Source Sets | Indiana University-Purdue University Indianapolis |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
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