Cobalt-Incorporated Hydroxyapatite Conditioned Media Promotes In Vitro Scratch Wound Healing and Mesenchymal Stem Cell Migration

Cell migration of mesenchymal stem cells (MSCs) is critical for bone healing and remodeling. Cobalt is a well-known hypoxia mimic, which can enhance MSC migration. Therefore, the objective of this study was to investigate the migratory response of MSCs to a developed cobalt-incorporated hydroxyapatite (HACo) material. HACo was fabricated by a simple ion exchange procedure at concentrations ranging from 40 to 8000 μM into disc shape. HACo discs were incubated in the media and conditioned media (CM; HACo_CM) were collected for MSC culture. HA_CM served as a control. MSCs were cultured until reaching 90% confluence before the wound was generated by scraping. Time-lapse imaging of wound migration was monitored, recorded, and assessed. Statistical analysis was performed by one-way ANOVA followed by a Dunnett's test. The wound area gradually declined from 0 to 40 h for all samples. HACo_CM at 40 µM (HACo40_CM) promoted wound closure at the early period of wound healing. Both HACo40_CM and HACo8000_CM enhanced the distance and velocity of individual cell migration. However, only HACo40_CM affected cell persistence and direction at the early period of cell migration. Exposure to HACo_CM accelerated the speed of MSC migration, which is necessary for wound healing. The migratory ability of individual cells could help the rate of wound healing. Therefore, HACo materials may serve as potential biomaterials for enhanced bone healing.