Ma. Attawia et al., IN-VITRO BONE BIOCOMPATIBILITY OF POLY(ANHYDRIDE-CO-IMIDES) CONTAINING PYROMELLITYLIMIDOALANINE, Journal of orthopaedic research, 14(3), 1996, pp. 445-454
Poly(anhydride-co-imides) are currently under study for applications i
nvolving bone. The cytotoxicity of a series of poly(anhydride-co-imide
s) with osteoblast-like cells (MC3T3-E1) was evaluated. The imide comp
onent of the copolymers was based on pyromellitylimidoalanine and the
anhydride component was based on either sebacic acid or 1,6-bis(carbox
yphenoxy)hexane. Cell adhesion and proliferation on the sur faces of t
he polymer discs were observed by environmental scanning electron micr
oscopy. During the first 24 hours of attachment, the cells showed norm
al morphology when cultured on copolymers containing 1,6-bis(carboxyph
enoxy)hexane. The cells did not adhere to the polymers containing seba
cic acid, probably due to the rapid degradation of the polymer surface
s. Concurrently, the effects of polymer breakdown products on osteobla
st-like cells were evaluated by studying their proliferation (cell num
bers), viability (dye exclusion), morphology (light microscopy), and p
henotypic expression. The morphology of osteoblast-like cells cultured
in the presence of the polymer breakdown products pyromellitylimidoal
anine and pyromellitic acid was found to be similar to that of the sam
e cells grown on tissue culture polystyrene and consisted of a charact
eristic polygonal shape. With use of a monoclonal antibody to osteocal
cin, these cells were shown to demonstrate preserved osteoblast phenot
ype with growth over a 21-day period. In addition, the cells reached c
onfluency after 3-4 days, similar to cells grown on tissue culture pol
ystyrene. This in vitro evaluation showed that the poly(anhydride-co-i
mides) evaluated are non-cytotoxic and may be viable biomaterials for
orthopaedic applications.