Contents lists available at ScienceDirect Polymer journal homepage: www.elsevier.com/locate/polymer High-performance porous PLLA-based scaffolds for bone tissue engineering: Preparation, characterization, and in vitro and in vivo evaluation Jiajun Ju a , Xiangfang Peng a , Keqing Huang c , Lengwan Li a , Xianhu Liu d , Chandani Chitrakar e , Lingqian Chang f , Zhipeng Gu c, ⁎⁎ , Tairong Kuang a,b,* a The Key Laboratory of Polymer Processing Engineering of Ministry of Education, South China University of Technology, Guangzhou, 510640, PR China b College of Material Science and Engineering, Zhejiang University of Technology, Hangzhou, 310014, PR China c Key Laboratory of Sensing Technology and Biomedical Instrument of Guangdong Province, School of Biomedical Engineering, Sun Yat-sen University, Guangzhou, 510006, PR China d The Key Laboratory of Advanced Materials Processing and Mold of Ministry of Education, Zhengzhou University, Zhengzhou, 450002, PR China e Department of Biomedical Engineering, University of North Texas, Denton, TX, 76203, USA f Institute of Nanotechnology for Single Cell Analysis (INSCA), Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, PR China HIGHLIGHTS • Porous PLLA-based scaffolds are successfully fabricated by structural manipulation and Sc-CO 2 foaming. • Incorporation of PEG into PLLA scaffolds improves hydrophilicity, biodegradability and compression strength significantly. • In vitro and in vivo biocompatibility of the structured PEG5 foam is investigated. • The structured PEG5 foam supports cell attachment and growth. • The obtained porous PLLA-based scaffolds are promising substrates for bone tissue engineering. ARTICLE INFO Keywords: PLLA-based scaffolds Structural manipulation Sc-CO 2 foaming Degradability Hydrophilicity In vitro and in vivo ABSTRACT Porous poly (L-lactic acid) (PLLA)-based tissue engineering scaffolds have gained growing interests due to their unique structures and properties. However, the simple and green fabrication of PLLA-based scaffolds with uniform and interconnected pore structure, good degradability and hydrophobicity, and excellent biocompat- ibility remain a major challenge. Herein, we developed a facile, cost-effective and eco-friendly structural ma- nipulation processing with supercritical carbon dioxide (Sc-CO 2 ) foaming technique to prepare porous PLLA/ poly (ethylene glycol) (PEG) (95/5 wt%) scaffolds. First, structural manipulation processing was used to ma- nipulate the formation of oriented crystal structure in a PLLA matrix, which could slow down the gas escaping during the Sc-CO 2 foaming process. Subsequently, the Sc-CO 2 foaming process was utilized to form 3D porous scaffolds, which are suitable for the cell growth, migration and proliferation. The fabricated porous biode- gradable scaffold exhibited high porosity (90.3%), uniform and interconnected open-pores, good strengths (11.9 MPa/(g·cm 3 )), degradabilities and hydrophilicities (75.7 ± 2.1°), as well as excellent in vitro biocompatibilities. For in vivo application, a rabbit model with bone defects was utilized, and both the histological analysis and immunohistochemical analysis results revealed that the obtained porous PLLA/PEG scaffolds support bone tissue engineering. 1. Introduction Nowadays, poly (L-lactide acid) (PLLA), which is a biodegradable and biocompatible synthetic polymer, is widely believed to be used as tissue engineering scaffold due to its good mechanical characteristics and biomedical performance [1–4]. Ideal PLLA scaffolds should have high porosity with interconnected pore structure to ensure cellular penetration and adequate transport of nutrients to cells [5,6]. https://doi.org/10.1016/j.polymer.2019.121707 Received 11 June 2019; Received in revised form 6 August 2019; Accepted 12 August 2019 * Corresponding author. ⁎⁎ Corresponding author. E-mail addresses: guzhp@mail.sysu.edu.cn (Z. Gu), ktrmonarch0914@gmail.com, ktrmonarch0914@gmail.com (T. Kuang). Polymer 180 (2019) 121707 Available online 13 August 2019 0032-3861/ © 2019 Elsevier Ltd. All rights reserved. T