Investigation of Human Dental Pulp Cells on a Potential Injectable Poly(lactic-co-glycolic acid) Microsphere Scaffold

Abstract Introduction 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 × 105 cells/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.