title: Investigation of Human Dental Pulp Cells on a Potential Injectable Poly(lactic-co-glycolic acid) Microsphere Scaffold.
abstract: BACKGROUND
  Poly(lactic-co-glycolic acid) (PLGA) has been extensively explored in the tissue engineering field with good biocompatibility and biodegradability. PLGA microspheres' injectable potency makes it highly desirable in dentin-pulp complex regeneration. Therefore, we investigated the cell adhesion, proliferation, odontogenic differentiation, and matrix mineralization of human dental pulp cells (HDPCs) on a PLGA microsphere scaffold. We hypothesized that this scaffold might be suitable for dentin-pulp complex regeneration.
  
  
  METHODS
  PLGA microsphere scaffolds were fabricated using the double-emulsion solvent extraction technique with or without type I collagen surface modification. HDPCs were isolated from freshly extracted premolar or third molar teeth with patients' informed consent and ethical approval. Fourth-passage HDPCs (1 × 105cells/ml) were seeded onto surface-modified or -unmodified PLGA microspheres and cultured in vitro. Cell adhesion, proliferation, and alkaline phosphatase activity were evaluated at different time points. Odontogenic-related gene expression (DMP1, DSPP, COL1, OPN, and OCN) were analyzed using quantitative real-time polymerase chain reaction. After 8 weeks of culture, samples were observed under scanning electron microscopy.
  
  
  RESULTS
  Surface modification using type I collagen significantly enhanced HDPC attachment to the PLGA microspheres and promoted cell spreading. Alkaline phosphatase activity and odontogenic-related gene expression of HDPCs cultured with PLGA microsphere scaffolds were enhanced significantly compared with HDPCs cultured without PLGA microsphere scaffolds. After 8 weeks of culture, HDPCs combined with PLGA microspheres formed 3-dimensional structures. Partial degradation of the scaffolds and matrix mineralization were also observed.
  
  
  CONCLUSIONS
  HDPCs can adhere to the PLGA microspheres, proliferate and differentiate into odontoblastlike cells, and form a 3-dimensional complex with matrix mineralization. This study may provide insight into the clinical dentin-pulp complex restoration with HDPCs and PLGA microsphere constructs.
authors.affiliation: Research Center, Tianjin Stomatological Hospital, Tianjin, China. Electronic address: zouhuiru@163.com.
authors.forename: Huiru
authors.initials: H
authors.lastname: Zou
authors.affiliation: Research Center, Tianjin Stomatological Hospital, Tianjin, China.
authors.forename: Guanhua
authors.initials: G
authors.lastname: Wang
authors.affiliation: Research Center, Tianjin Stomatological Hospital, Tianjin, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Song
authors.affiliation: Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, China.
authors.forename: Xudong
authors.initials: X
authors.lastname: Shi
mesh_terms: D024042:Collagen Type I / Q000627:therapeutic use; D003782:Dental Pulp / Q000166:cytology* / Q000502:physiology; D006801:Humans; D019344:Lactic Acid / Q000627:therapeutic use; D008863:Microspheres; D011100:Polyglycolic Acid / Q000627:therapeutic use; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D012038:Regeneration / Q000502:physiology; D054457:Tissue Scaffolds
chemical_list: D024042:Collagen Type I; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid
keywords: Human dental pulp cells; microsphere; odontogenic differentiation; poly(lactic-co-glycolic acid)