title: Mechanical and thermal property characterization of poly-l-lactide (PLLA) scaffold developed using pressure-controllable green foaming technology.
abstract: Poly-l-lactide (PLLA) is one of the most promising biological materials used for tissue engineering scaffolds (TES) because of their excellent biodegradability and tenability. Here, microcellular PLLA foams were fabricated by pressure-controllable green foaming technology. Scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), wide angle X-ray diffraction measurement (WAXRD), thermogravimetric (TG) analysis, reflection-Fourier transform infrared (FTIR) analysis, enzymatic degradation study and MTT assay were used to analyze the scaffolds' morphologies, structures and crystallinities, mechanical and biodegradation properties, as well as their cytotoxicity. The results showed that PLLA foams with pore sizes from 8 to 103μm diameters were produced when the saturation pressure decreased from 7.0 to 4.0MPa. Through a combination of StepScan DSC (SSDSC) and WAXRD approaches, it was observed in PLLA foams that the crystallinity, highly-oriented metastable state and rigid amorphous phase increased with the increasing foaming pressure. It was also found that both the glass transition temperature and apparent enthalpy of PLLA significantly increased after the foaming process, which suggested that the changes of microcellular structure could provide PLLA scaffolds better thermal stability and elasticity. Moreover, MTT assessments suggested that the smaller pore size should benefit cell attachment and growth in the scaffold. The results of current work will give us better understanding of the mechanisms involved in structure and property changes of PLLA at the molecular level, which enables more possibilities for the design of PLLA scaffold to satisfy various requirements in biomedical and green chemical applications.
authors: Center of Analysis and Testing, Nanjing Normal University, Nanjing 210023, China; School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China.
authors: Shen-Jun
authors: SJ
authors: Sheng
authors: Department of Physics and Astronomy, Rowan University, Glassboro, NJ 08028, USA; Department of Biomedical and Translational Sciences, Rowan University, Glassboro, NJ 08028, USA.
authors: Xiao
authors: X
authors: Hu
authors: Center of Analysis and Testing, Nanjing Normal University, Nanjing 210023, China; Department of Physics and Astronomy, Rowan University, Glassboro, NJ 08028, USA. Electronic address: wangfang@njnu.edu.cn.
authors: Fang
authors: F
authors: Wang
authors: Key Laboratory of Optoelectronics of Jiangsu Province, School of Physics and Technology, Nanjing Normal University, Nanjing 210023, China.
authors: Qing-Yu
authors: QY
authors: Ma
authors: Center of Analysis and Testing, Nanjing Normal University, Nanjing 210023, China.
authors: Min-Fen
authors: MF
authors: Gu
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D002152:Calorimetry, Differential Scanning / Q000379:methods; D004548:Elasticity; D008422:Materials Testing / Q000379:methods; D008855:Microscopy, Electron, Scanning / Q000379:methods; D011091:Polyesters / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011312:Pressure; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013696:Temperature; D013816:Thermodynamics; D013818:Thermogravimetry / Q000379:methods; D023822:Tissue Engineering / Q000379:methods; D054457:Tissue Scaffolds / Q000737:chemistry*; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; D011108:Polymers; C033616:poly(lactide)
keywords: Biodegradation; Gas foaming; Glass transition temperature; Mesophase; Poly-l-lactide; Rigid amorphous