Human neutrophils reaction to the biodegraded nano-hydroxyapatite/collagen and nano-hydroxyapatite/collagen/poly(L-lactic acid) composites

The impact of biodegraded nano-hydroxyapatite/collagen (nHAC) composite and nano-hydroxyapatite/ collagen/poly(L-lactic acid) (nHAC/PLA) scaffold composite on neutrophils reaction was evaluated in vitro. Neutrophils were separated from human peripheral blood of healthy subjects. The nHAC and nHAC/PLA materials were immersed in the D-Hanks' Balanced Salt Solution (DHBSS) for I day, 7 days and 2, 4, 8 weeks (37 degrees C) as testing solution, which mixed with the neutrophils for 1 h. Both of the nHAC and nHAC/PLA materials were shown the same cell Survival rate as blank control, but the lactate dehydrogenase (LDH) and tumor necrosis factor alpha (TNF-alpha) released from the neutrophils were increased significantly after the 2 weeks in nHAC sample. The possible reason relied on the high concentration of calcium due to the quick biodegradation of the nHAC material. Before 2 weeks, the LDH value of nHAC/PLA is higher than that of nHAC sample that corresponded to the initial PLA degradation in vitro. This study provided the biocompatibility test of neutrophils other than common methods, such as osteoblastic cells for biomimetic materials. Moreover, it demonstrated the calcium concentration stimulating effect for cytokine release from neutrophils. (c) 2005 Wiley Periodicals, Inc.