title: Effect of in vitro degradation of poly(D,L-lactide)/beta-tricalcium composite on its shape-memory properties.
abstract: The in vitro degradation characteristic and shape-memory properties of poly(D,L-lactide) (PDLLA)/beta-tricalcium phosphate (beta-TCP) composites were investigated because of their wide application in biomedical fields. In this article, PDLLA and crystalline beta-TCP were compounded and interesting shape-memory behaviors of the composite were first investigated. Then, in vitro degradation of the PDLLA/beta-TCP composites with weight ratios of 1:1, 2:1, and 3:1 was performed in phosphate buffer saline solution (PBS) (154 mM, pH 7.4) at 37 degrees C. The effect of in vitro degradation time for PDLLA/beta-TCP composites on shape-memory properties was studied by scanning electron microscopy, differential scanning calorimetry, gel permeation chromatography, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The changes of structural morphology, glass transition temperature (T(g)), molecular weight, and weight loss of composites matrix and pH change of degradation medium indicated that shape-memory effects at different degradation time were nonlinearly influenced because of the breaking down of polymer chain and the formation of degradation products. Furthermore, the results from XRD and FTIR implied that the degradation products, for example, hydroxyapatite (HA), calcium hydrogen phosphate (CaHPO(4)), and calcium pyrophosphate (Ca(2)P(2)O(7)) phases also had some effects on shape-memory properties during the degradation.
authors.affiliation: School of Materials Science and Engineering, Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, People's Republic of China.
authors.forename: Xiaotong
authors.initials: X
authors.lastname: Zheng
authors.forename: Shaobing
authors.initials: S
authors.lastname: Zhou
authors.forename: Xiongjun
authors.initials: X
authors.lastname: Yu
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Li
authors.forename: Bo
authors.initials: B
authors.lastname: Feng
authors.forename: Shuxin
authors.initials: S
authors.lastname: Qu
authors.forename: Jie
authors.initials: J
authors.lastname: Weng
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D001835:Body Weight; D018786:Bone Substitutes / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D019344:Lactic Acid / Q000031:analogs & derivatives / Q000737:chemistry; D008422:Materials Testing; D008956:Models, Chemical; D008970:Molecular Weight; D011091:Polyesters / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013696:Temperature; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: C510584:2,2'-bis(2-oxazoline) linked poly(lactic acid); D001672:Biocompatible Materials; D018786:Bone Substitutes; D002130:Calcium Phosphates; D011091:Polyesters; D011108:Polymers; C485817:beta-tricalcium phosphate; D019344:Lactic Acid; C033616:poly(lactide)