Poly(L-lactic acid)/hydroxyapatite nanofibrous scaffolds for bone tissue engineering

Abstract

This study analyzed osteogenic differentiation of cells in a poly(L-lactic acid) (PLLA) / hydroxyapatite (HA) nanofibrous scaffold. Our bone tissues are composed of nanostructural hydroxyapatite and collagen fibers which provide an extracellular matrix. Since HA is chemically similar to the inorganic mineral component of bones, it is one of few materials that are classed as bioactive. The ability to integrate in bone structures and support bone ingrowths, HA is used in orthopedic, dental and maxillofacial applications. Synthetic polymer PLLA is often used as polymeric material and has some features, which make it useful for combining with HA. Fibers of PLLA may strengthen HA and its good bioresorbility provides space for tissue extension.

In our study, the electrospinning was carried out at various percentage of HA. We hypothesize that the increase of HA concentration in PLLA/HA nanofiber, cells are enhanced mineralization. For this purpose, MC3T3 pre-osteoblast cell seeded on each percent nanofiber and cultured in the presence of β-glycerophosphate and ascorbic acid to achieve an osteoblast phenotype. Afterward, to examine the effect of HA on osteogenic differentiation, DNA levels, alkaline phosphatase (ALP) activity, calcium deposition was measured and reverse transcriptase - polymerase chain reaction (RT-PCR) was used for osteogenic marker. The scaffolds were observed with scanning electron microscopy and stained with von Kossa for histological analysis.

Cell behavior varied depending on the HA percentage. Differentiation is relatively higher in the PLLA/HA nanofiber containing a high HA concentration and this result showed that these nanofiber promoted osteoblast functions. The present study implicated PLLA/HA nanofibers as a proper material in the future design of materials for tissue engineering of bone.