title: Fast degradable citrate-based bone scaffold promotes spinal fusion.
abstract: It is well known that high rates of fusion failure and pseudoarthrosis development (5~35%) are concomitant in spinal fusion surgery, which was ascribed to the shortage of suitable materials for bone regeneration. Citrate was recently recognized to play an indispensable role in enhancing osteconductivity and osteoinductivity, and promoting bone formation. To address the material challenges in spinal fusion surgery, we have synthesized mechanically robust and fast degrading citrate-based polymers by incorporating N-methyldiethanolamine (MDEA) into clickable poly(1, 8-octanediol citrates) (POC-click), referred to as POC-M-click. The obtained POC-M-click were fabricated into POC-M-click-HA matchstick scaffolds by compositing with hydroxyapatite (HA) for interbody spinal fusion in a rabbit model. Spinal fusion was analyzed by radiography, manual palpation, biomechanical testing, and histological evaluation. At 4 and 8 weeks post surgery, POC-M-click-HA scaffolds presented optimal degradation rates that facilitated faster new bone formation and higher spinal fusion rates (11.2±3.7, 80±4.5 at week 4 and 8, respectively) than the poly(L-lactic acid)-HA (PLLA-HA) control group (9.3±2.4 and 71.1±4.4) (p<0.05). The POC-M-click-HA scaffold-fused vertebrates possessed a maximum load and stiffness of 880.8±14.5 N and 843.2±22.4 N/mm, respectively, which were also much higher than those of the PLLA-HA group (maximum: 712.0±37.5 N, stiffness: 622.5±28.4 N/mm, p<0.05). Overall, the results suggest that POC-M-click-HA scaffolds could potentially serve as promising bone grafts for spinal fusion applications.
authors.affiliation: Academy of Orthopedics, Guangdong Province, Department of Orthopedic Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, 510630, China ; Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou 510515, China.
authors.forename: Jiajun
authors.initials: J
authors.lastname: Tang
authors.affiliation: Department of Biomedical Engineering, Materials Research Institute, The Huck Institutes of The Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Jinshan
authors.initials: J
authors.lastname: Guo
authors.affiliation: Academy of Orthopedics, Guangdong Province, Department of Orthopedic Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, 510630, China ; Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou 510515, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Li
authors.affiliation: Academy of Orthopedics, Guangdong Province, Department of Orthopedic Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, 510630, China ; Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou 510515, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Yang
authors.affiliation: Academy of Orthopedics, Guangdong Province, Department of Orthopedic Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, 510630, China ; Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou 510515, China.
authors.forename: Denghui
authors.initials: D
authors.lastname: Xie
authors.affiliation: Academy of Orthopedics, Guangdong Province, Department of Orthopedic Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, 510630, China ; Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou 510515, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.affiliation: Academy of Orthopedics, Guangdong Province, Department of Orthopedic Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, 510630, China ; Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou 510515, China.
authors.forename: Shengfa
authors.initials: S
authors.lastname: Li
authors.affiliation: Medical imaging department, Guangdong Province, The Third Affiliated Hospital of Southern Medical University, Guangzhou, 510630, China.
authors.forename: Shaolin
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Biomedical Engineering, Materials Research Institute, The Huck Institutes of The Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Gloria B
authors.initials: GB
authors.lastname: Kim
authors.affiliation: Academy of Orthopedics, Guangdong Province, Department of Orthopedic Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, 510630, China ; Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou 510515, China.
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Bai
authors.affiliation: Academy of Orthopedics, Guangdong Province, Department of Orthopedic Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, 510630, China.
authors.forename: Zhongmin
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Biomedical Engineering, Materials Research Institute, The Huck Institutes of The Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Jian
authors.initials: J
authors.lastname: Yang