The effects on antioxidant enzymes of PMMA/hydroxyapatite nanocomposites/composites

In this study, polymer-ceramic nanocomposites and/or composites were prepared by solution removal method using poly(methylmethacrylat) (PMMA) and nano-hydroxyapatite (nHA). They were characterized using X-ray diffraction (XRD), Fourier transform infrared-attenuated total reflection spectroscopy (FTIR-ATR), and differential thermal analysis/thermogravimetry (DTA/TG). Their effects and biocompatibilities on antioxidant enzymes were also investigated in detail. It has been shown that nHA was dramatically dispersed at nanoscale in the polymer matrix. The interaction occurred between OH groups of nHA and carbonyl groups of polymer and introduction of ceramic into the polymer matrix generally resulted in an increase in thermal stability. Nanocomposites and composites had different effects on enzyme activities. Samples synthesized in acetone increased enzyme activities for glutathione reductase (GR) and glucose-6 phosphate dehydrogenase (G6PD) enzymes, while inhibiting glutathione peroxidase (GPx) and catalase (CAT) enzyme activities. On the other hand, samples synthesized in tetrahydrofuran (THF) exhibited inhibitory behavior for G6PD and CAT enzymes. The samples synthesized in different media did not show any regularity on enzyme activities. The nanocomposites and/or composites prepared in acetone media were better hemocompatible than those in THF.