Publication:

An in-vitro medical device material biocompatibility study using primary cell cultures of rat osteoblasts

Background We questioned if simple chemical methods could be applied as a possible biocompatibility test for biomaterials.

Methods In a qualitative experiment, osteoblasts cells harvested from newly born (3-5) day old sprague-dawley rats were cultivated in growth medium in a controlled environment in the presence of titanium (Ti) (American Elements®), cobalt-chromium (Co-Cr) (Nobilium®), bio-activated rattan wood, orthopaedic bone cement (CEMEX®), implant fixtures (Astra TDC), and resorbable suture material (Poly-Gly-Lac) (VICRYL®). Sample aliquots were withdrawn periodically over 16 days. One and two-dimensional polyacrylamide gel electrophoresis (PAGE) as well as isoelectric focusing (IEF) produced spots that were subjected to enzyme digestion and molecular weight determination. In a follow-up quantitative experiment, the same samples, except for those containing CEMEX and VICRYL, were prepared. The alkaline phosphatase (ALP) activity was monitored continuously using the colorimetric Stanbio® kits. The ALP activities at days 2, 4, 8, 12, and 16, designated as a longitudinal variable, TIME, were analysed, using SPSS V.22, as a mixed ANOVA model with TIME as a repeated measure and the material type as an independent factor.

Results The IEF and second dimension PAGE produced an additional spot for Ti at pH(I) of 5-6. This was identified as IQUB_RAT IQ, a ubiquitin-like domain, molecular weight 2.6 kDa. This method was able to find finite differences in osteoblast activity after initial exposure to a foreign body. Both the ALP activity changes from one day to the next for all materials and the TIME-material type interaction effects were significant (p=0.000).

Conclusions This technique is suitable for use with human cell lines or clones. Experiments like these reduce the need for animal testing.