title: Injectable alginate/hydroxyapatite gel scaffold combined with gelatin microspheres for drug delivery and bone tissue engineering.
abstract: Injectable and biodegradable alginate-based composite gel scaffolds doubly integrated with hydroxyapatite (HAp) and gelatin microspheres (GMs) were cross-linked via in situ release of calcium cations. As triggers of calcium cations, CaCO3 and glucono-D-lactone (GDL) were fixed as a mass ratio of 1:1 to control pH value ranging from 6.8 to 7.2 during gelation. Synchronously, tetracycline hydrochloride (TH) was encapsulated into GMs to enhance bioactivity of composite gel scaffolds. The effects of HAp and GMs on characteristics of gel scaffolds, including pH value, gelation time, mechanical properties, swelling ratio, degradation behavior and drug release, were investigated. The results showed that HAp and GMs successfully improved mechanical properties of gel scaffolds at strain from 0.1 to 0.5, which stabilized the gel network and decreased weight loss, as well as swelling ratio and gelation time. TH could be released from this composite gel scaffold into the local microenvironment in a controlled fashion by the organic/inorganic hybrid of hydrogel network. Our results demonstrate that the HAp and GMs doubly integrated alginate-based gel scaffolds, especially the one with 6% (w/v) HAp and 5% (w/v) GMs, have suitable physical performance and bioactive properties, thus provide a potential opportunity to be used for bone tissue engineering. The potential application of this gel scaffold in bone tissue engineering was confirmed by encapsulation behavior of osteoblasts. In combination with TH, the gel scaffold exhibited beneficial effects on osteoblast activity, which suggested a promising future for local treatment of pathologies involving bone loss.
authors.affiliation: School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
authors.forename: Jingxuan
authors.initials: J
authors.lastname: Yan
authors.affiliation: School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
authors.forename: Yuting
authors.initials: Y
authors.lastname: Miao
authors.affiliation: School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China. Electronic address: hptan@njust.edu.cn.
authors.forename: Huaping
authors.initials: H
authors.lastname: Tan
authors.affiliation: School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
authors.forename: Tianle
authors.initials: T
authors.lastname: Zhou
authors.affiliation: Department of Orthopaedics, Jinling Hospital, Nanjing 210002, China.
authors.forename: Zhonghua
authors.initials: Z
authors.lastname: Ling
authors.affiliation: Department of Orthopaedics, Jinling Hospital, Nanjing 210002, China. Electronic address: 13813889089@139.com.
authors.forename: Yong
authors.initials: Y
authors.lastname: Chen
authors.affiliation: School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Xing
authors.affiliation: School of Material Engineering, Jinling Institute of Technology, Nanjing 211169, China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Hu
mesh_terms: D000464:Alginates / Q000737:chemistry*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D019245:Compressive Strength; D004337:Drug Carriers / Q000737:chemistry* / Q000633:toxicity; D065546:Drug Liberation; D017886:Durapatite / Q000737:chemistry*; D005780:Gelatin / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006801:Humans; D020100:Hydrogels / Q000737:chemistry / Q000633:toxicity; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D016062:Porosity; D012212:Rheology; D013752:Tetracycline / Q000737:chemistry / Q000378:metabolism; D023822:Tissue Engineering
chemical_list: D000464:Alginates; D004337:Drug Carriers; D006603:Hexuronic Acids; D020100:Hydrogels; D020723:Glucuronic Acid; D005780:Gelatin; D017886:Durapatite; D013752:Tetracycline
keywords: Alginate; Drug delivery; Hydrogels; Hydroxyapatite; Microspheres; Tissue engineering