Kd. Chesmel et al., CELLULAR-RESPONSES TO CHEMICAL AND MORPHOLOGIC ASPECTS OF BIOMATERIALSURFACES .2. THE BIOSYNTHETIC AND MIGRATORY RESPONSE OF BONE CELL-POPULATIONS, Journal of biomedical materials research, 29(9), 1995, pp. 1101-1110
The biosynthetic and migratory response of bone cells to changes in bo
th surface composition and morphology of polystyrene (PS) substrates w
as examined. A system was devised wherein micromachined silicon wafers
were used as templates to solvent-cast PS replicas [using 0, 1, or 2
wt % styrene (S) monomer additions] with either 0.5- or 5.0-mu m-deep
surface grooves. Smooth replicas (0% S) served as the control surfaces
. The chemical and morphologic characteristics of the nine unique mode
l biomaterial surfaces (MBSs) produced using this system were document
ed and were found to be distinct. For the biosynthetic studies, bone c
ells isolated from neonatal rat calvaria were plated onto the MBSs and
labeled at postconfluence with [C-14]proline for 24 h. Total DNA per
surface, total newly synthesized collagenous (CP), and noncollagenous
protein (NCP) (cell associated and secreted) were determined. Cell-ass
ociated CP was found to increase significantly for the bone cells cult
ured on the substrates with 0.5-mu m grooves and 2% S (P <.05). Cell-a
ssociated NCP was found to be elevated for all 2% S substrates and for
the 0.5-mu m grooves substrates with 1% S. For the migration studies,
bone cells were plated first onto 5-mm nitrocellulose disks that were
attached to standard Petri dishes using a plasma clot. At confluence,
the disks were removed aseptically and placed on the replicas. The ce
llular area occupied as a result of the outward migration of the bone
cells was measured after 4 days of culture using an image analysis sys
tem. An average velocity for the leading edge of bone cell populations
on each of the nine MBSs was calculated: Cells on surfaces with eithe
r 1% S or 5.0-mu m grooves displayed significantly higher velocities t
han did the control cultures. A significant interaction effect between
chemistry and morphology was observed. The biosynthetic and migratory
responses of in vitro cultures of bone cells were not predictable fro
m the observations of the cellular responses to the individual feature
s, but appeared to depend on cellular responses to more than one subst
rate factor. (C) 1995 John Wiley and Sons, Inc.