Repair of Bone Defect in Femoral Condyle Using Microencapsulated Chitosan, Nanohydroxyapatite/Collagen and Poly(L‐Lactide)‐Based Microsphere‐Scaffold Delivery System

Abstract

Bone repair ability of microencapsulated chitosan, nanohydroxyapatite/collagen (nHAC), and poly(L-lactide) (PLLA)-based microsphere-scaffold delivery system was investigated in present research, with nHAC/PLLA composite scaffold as a control. Chitosan microspheres (CMs) encapsulated with bone morphogenetic protein-2-derived synthetic peptide were incorporated into nHAC and PLLA-based matrix via a thermally induced phase separation method, in which dioxane was used as the solvent for PLLA. Compared with the rapid release from CMs, the synthetic peptide was delivered from CMs/nHAC/PLLA microsphere-scaffold composite in a temporally controlled manner, depending on the degradation of both incorporated CMs and PLLA matrix. MC3T3-E1 osteoblastic cells were seeded into nHAC/PLLA and CMs/nHAC/PLLA scaffolds, respectively, and in vitro cytocompatibility was tested by scanning electron microscopy and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The results indicated that, with the appearance of CMs in microsphere-scaffold composite, the osteoblasts exhibit better morphology and proliferation ability. In vivo tissue compatibility was evaluated by transplanting the scaffolds into rabbit femoral condyles with a defect 6 mm in diameter. After implanting for 4, 8, and 12 weeks, respectively, radiographic and histological observation revealed that the CMs/nHAC/PLLA composite can accelerate the regeneration of cancellous bone defect as compared with the nHAC/PLLA scaffold. The results demonstrated that the CMs/nHAC/PLLA possesses better biocompatibility, which should be attributed to both the incorporated chitosan component and the encapsulated bioactive synthetic peptide. The promising CMs/nHAC/PLLA microsphere-scaffold composite can be used as delivery system for multiple bioactive factors or as inductive implant scaffold for bone regeneration.

Versatility of Chitosan-Based Biomaterials and Their Use as Scaffolds for Tissue Regeneration

“…The combination of CS with other natural polymers, such as collagen, gelatin, and silk fibroin, synthetic polymers such as PLGA, and compounds of calcium and phosphate, such as HA, permits an improvement in specific properties like solubility, biodegradation, and mechanical performance of CS as a function of the tissue to be regenerated [10]. In fact, some studies have clearly shown that the association of CS with collagen [42, 44, 68], silk fibroin [73], and HA [45, 57, 58] was capable of promoting greater tissue regeneration than pure CS, as in these studies pure or combined CS scaffolds were implanted, making it possible to establish a comparison between them. However, in the vast majority of studies evaluating CS combined with other biomaterials, the favorable results obtained cannot be attributed to the associations, as pure CS was neither evaluated nor used as a control [8, 30, 32, 41, 46, 48, 49, 53, 54, 62, 63, 67, 71, 76, 77, 80, 81, 83, 86, 88].…”

A review on carrier systems for bone morphogenetic protein‐2

“…The result suggested that the activity of aminobiotinated rhBMP‐2 has been found more than the carboxy‐biotinated rhBMP‐2, but in the presence of avidin the scenario become reverse. Also, the phenol/imidazole‐treated rhBMP‐2 failed to retain the rhBMP‐2 bioactivity . Moreover, Uludag et al showed that protein pI has influence on early retention of rhBMP‐2 …”

Artificial Organs 2011: A Year in Review

“…Xufeng Niu et al. (127) of Tsinghua University, Beijing, China investigated the repair of bone defects in femoral condyle using microencapsulated chitosan (CHIT), nanohydroxyapatite/collagen (nHAC), and poly(l‐lactide)‐based microsphere–scaffold delivery system with nHAC/PLLA composite scaffold as a control. Compared with the rapid release from chitosan microspheres (CMs), the synthetic peptide was delivered from CMs/nHAC/PLLA microsphere–scaffold composite in a temporally controlled manner.…”