title: Carboxymethylcellulose with phenolic hydroxyl microcapsules enclosinggene-modified BMSCs for controlled BMP-2 release in vitro.
abstract: OBJECTIVE
  The present study aimed to develop microparticles of phenolic hydroxyl derivative of carboxymethylcellulose (CMC-Ph) via Co-flow microfluidics technology and encapsulated gene-modified rat bone mesenchymal stem cells (BMSCs) for the detection of the growth factor release was controlled by Tet-on system. Meanwhile, we investigated the effect of the CMC-Ph microcapsules and Lentiviral transduction on osteogenesis of BMP2-BMSCs.
  
  
  METHODS
  The middle size of CMC-Ph microcapsules was prepared by optimized co-flow microfluidics through ejecting fluid CMC-Ph suspension (mixed with HRP) into co-flowing liquid paraffin which blends H2O2at priority. The Lentivirus-encoding hBMP-2 and Tet-On system were constructed and amplified by RT-PCR, then encapsulated in the microcapsules. The cellular viability of CMC-Ph microparticles was assessed by Live/dead staining and metabolic activity was estimated by colorimetric assay kit. In addition, BMP-2 secretion and kinetic studies were determined by ELISA, alkaline phosphatase (ALP) activity was evaluated using ALP assay kit, and ALP staining as well as mineral calcium deposition was detected by alizarin red S staining.
  
  
  RESULTS
  The diameter of CMC-Ph microparticles was controlled between 100 and 150 μm by altering the flow speed of liquid paraffin and then encapsulated bone morphogenetic protein 2 (BMP-2) gene modified BMSCs transduced by a lentiviral vector. Moreover, the mitochondrial activity of the encapsulated cells was maintained at least 24 d and BMP-2 protein secretion into the supernatant sustained for 35 d without significant loss of efficiency under the induction of the doxycycline. Furthermore, mineral deposition staining and ALP activity detection showed that encapsulated lentiviral-BMP2 transduced BMSCs possess more osteogenic differentiation potential than normal cells.
  
  
  CONCLUSIONS
  Co-flow microfluidics and phenolic hydroxyl derivative of carboxymethylcellulose (CMC-Ph) provide a promising strategy for cell-enclosed microcapsules in combination with BMP-2 gene and Tet-on system modified BMSCs and then controlled BMP-2 protein released effectively as well as promoted the osteogenic differentiation of BMSCs.
authors.affiliation: a Orthopaedic Department of the First Affiliated Hospital of Guangzhou Medical University , Guangdong Key Laboratory of Orthopaedic Technology and Implant Materials , Guangzhou , China.
authors.forename: Xiufan
authors.initials: X
authors.lastname: Du
authors.affiliation: a Orthopaedic Department of the First Affiliated Hospital of Guangzhou Medical University , Guangdong Key Laboratory of Orthopaedic Technology and Implant Materials , Guangzhou , China.
authors.forename: Fangli
authors.initials: F
authors.lastname: Huang
authors.affiliation: a Orthopaedic Department of the First Affiliated Hospital of Guangzhou Medical University , Guangdong Key Laboratory of Orthopaedic Technology and Implant Materials , Guangzhou , China.
authors.forename: Shujiang
authors.initials: S
authors.lastname: Zhang
authors.affiliation: a Orthopaedic Department of the First Affiliated Hospital of Guangzhou Medical University , Guangdong Key Laboratory of Orthopaedic Technology and Implant Materials , Guangzhou , China.
authors.forename: Yongchang
authors.initials: Y
authors.lastname: Yao
authors.affiliation: a Orthopaedic Department of the First Affiliated Hospital of Guangzhou Medical University , Guangdong Key Laboratory of Orthopaedic Technology and Implant Materials , Guangzhou , China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.affiliation: a Orthopaedic Department of the First Affiliated Hospital of Guangzhou Medical University , Guangdong Key Laboratory of Orthopaedic Technology and Implant Materials , Guangzhou , China.
authors.forename: Yushu
authors.initials: Y
authors.lastname: Chen
authors.affiliation: a Orthopaedic Department of the First Affiliated Hospital of Guangzhou Medical University , Guangdong Key Laboratory of Orthopaedic Technology and Implant Materials , Guangzhou , China.
authors.forename: Hongxuan
authors.initials: H
authors.lastname: Huang
authors.affiliation: a Orthopaedic Department of the First Affiliated Hospital of Guangzhou Medical University , Guangdong Key Laboratory of Orthopaedic Technology and Implant Materials , Guangzhou , China.
authors.forename: Bo
authors.initials: B
authors.lastname: Bai
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002214:Capsules; D002266:Carboxymethylcellulose Sodium / Q000737:chemistry*; D002454:Cell Differentiation / Q000235:genetics; D002470:Cell Survival; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D010012:Osteogenesis / Q000235:genetics; D010636:Phenols / Q000737:chemistry*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D014161:Transduction, Genetic
chemical_list: D055396:Bone Morphogenetic Protein 2; D002214:Capsules; D010636:Phenols; D012333:RNA, Messenger; D000469:Alkaline Phosphatase; D002266:Carboxymethylcellulose Sodium; D002118:Calcium
keywords: BMP-2; Phenolic hydroxyl derivative of carboxymethylcellulose (CMC-Ph); Tet-on system; lentiviral; microcapsules; osteogenic differentiation