Background: Hydroxyapatite (HA) was emerging as the most promising biomaterial owing
to its excellent bioactivity, biocompatibility, and high compressive strength for segmental bone defects.
However, due to the lack of synergistic signals of osteogenic cells or growth factors, attempts concerning
HA have not achieved an ideal therapeutical effect.
Objective: This work was intended to combine HA particles with nerve growth factor (NGF) to coaccelerate
the bone repair.
Method: To deal with the strong absorption on HA particles and short half-life of exogenous NGF, bovine
serum albumin (BSA) and silk fibroin (SF) were introduced.
Result: Protected with SF, maximum release rate was 49.8% at 48 h for 2 mg/ml SF used group while
the release rate was less than 5% without SF. PC-12 cells cultured in the NGF release fluid quit proliferation
and differentiated to neural phenotype, and approximately 9.5% of NGF loading released from
the particles within 48 h.
Conclusion: Protected with BSA, in vitro release showed no obvious effect on strong absorption for the
surface of HA particles, however, the drug loading of model protein decreased. Fortunately, SF demonstrated
the capacity of adjusting the release profile of protein by varying the amount of SF embedded
with no influence on drug loading and maintaining the bioactivity of NGF absorbed on HA particles.