Previous studies have shown that
esterase activity can degrade a variety of
polyurethanes (
PUs), including
polycarbonate-based
PUs (PCNUs). When cultured on PCNUs, differing in their chemistries, monocyte-derived macrophages (MDM) synthesized and secreted different amounts of both
cholesterol esterase (CE) and
monocyte-specific esterase (MSE). MDM were seeded on PCNUs synthesized with
hexane diisocyanate (HDI) or 4,4'-methylene-bis-phenyl diisocyanate (MDI),
PCN and [14C]butanediol (BD) in the ratio 3:2:1 (referred to as HDI321 or MDI321). The effect of
phenylmethylsulfonyl fluoride (PMSF, a
serine esterase and
proteinase inhibitor),
sodium fluoride (NaF, a MSE inhibitor) and
sodium taurocholate (
NaT, a CE stimulator) was assessed on degradation (measured by radiolabel release (RR)) and
esterase activity in MDM lysate. The results were compared to the effect that these
reagents had on commercially available CE and carboxyl
esterase (CXE), which has a specificity similar to MSE. NaF inhibited CXE- and MDM-mediated RR to the same extent as for both PCNUs. However, the MDM-mediated RR from MDI321 was 1.8-times higher than HDI321 in the presence of
NaT (P = 0.005). This study suggests that the difference in diisocyanate chemistry may dictate the relative contribution of each
esterase to a specific material's degradation. This may be related to both the substrate specificity of each
esterase, as well as by the relative amount of each
esterase that the specific
biomaterial substrates induce the cells to synthesize and secrete.