title: Structural and degradation characteristics of an innovative porous PLGA/TCP scaffold incorporated with bioactive molecular icaritin.
abstract: Phytomolecules may chemically bind to scaffold materials for medical applications. The present study used an osteoconductive porous poly(l-lactide-co-glycolide)/tricalcium phosphate (PLGA/TCP) to incorporate an exogenous phytoestrogenic molecule icaritin to form a PLGA/TCP/icaritin composite scaffold material with potential slow release of icaritin during scaffold degradation. Accordingly, the present study was designed to investigate its in vitro degradation characteristics and the release pattern of icaritin at three different doses (74 mg, 7.4 mg and 0.74 mg per 100 g PLGA/TCP, i.e. in the PLGA/TCP/icaritin-H, -M and -L groups, respectively). A PLGA/TCP/icaritin porous composite scaffold was fabricated using a computer-controlled printing machine. The PLGA/TCP/icaritin scaffolds were incubated in saline at 37 °C for 12 weeks and the pure PLGA/TCP scaffold served as a control. During the 12 weeks in vitro degradation, the scaffolds in all four groups showed changes, including a decrease in weight, volume and pore size of the composite scaffold, while there was a decrease in acidity and an increase in Ca and lactic acid concentrations in the degradation medium, especially after 7 weeks. The rate of degradation was explained by the relationship with the content of icaritin incorporated into the scaffolds. The higher the icaritin content in the scaffolds, the slower the degradation could be observed during 12 weeks. After 12 weeks, the SEM showed that the surface of the PLGA/TCP and PLGA/TCP/icaritin-L groups was relatively smooth with a gradual decrease in number and size of the micropores, while the porous morphology on the surface of the PLGA/TCP/icaritin-M and PLGA/TCP/icaritin-H groups was partly maintained, accompanied by a decrease in phosphate (P) and calcium (Ca) contents at the surface. Though the mechanical property of the PLGA/TCP/icaritin scaffold decreased after degradation, its porous structure was maintained, which was essential for cell migration and ingrowth of newly regenerated tissues in vivo. The controlled release of icaritin from the composite scaffold reached about 70% of the incorporated icaritin into the degradation medium after 12 weeks. The above findings suggested that the structural and degradation properties of the porous composite PLGA/TCP/icaritin scaffold were dependent on icaritin concentrations. This innovative composite porous scaffold material developed in the present study may be used as a good scaffold material for enhancing bone repair, especially at high concentrations of icaritin. In vivo confirmation is, however, needed to substantiate our in vitro findings.
authors.affiliation: Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR, People's Republic of China.
authors.forename: Xin-Hui
authors.initials: XH
authors.lastname: Xie
authors.forename: Xin-Luan
authors.initials: XL
authors.lastname: Wang
authors.forename: Ge
authors.initials: G
authors.lastname: Zhang
authors.forename: Yi-Xin
authors.initials: YX
authors.lastname: He
authors.forename: Xiao-Hong
authors.initials: XH
authors.lastname: Wang
authors.forename: Zhong
authors.initials: Z
authors.lastname: Liu
authors.forename: Kai
authors.initials: K
authors.lastname: He
authors.forename: Jiang
authors.initials: J
authors.lastname: Peng
authors.forename: Yang
authors.initials: Y
authors.lastname: Leng
authors.forename: Ling
authors.initials: L
authors.lastname: Qin
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D001696:Biomechanical Phenomena; D001842:Bone and Bones; D002118:Calcium / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry*; D019245:Compressive Strength; D003470:Culture Media / Q000737:chemistry; D005419:Flavonoids / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D002130:Calcium Phosphates; D003470:Culture Media; D005419:Flavonoids; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; C018392:tricalcium phosphate; D002118:Calcium; C499403:icaritin