Development of isotopically labelled ⁶⁵Cu embedded PMMA-⁶⁵CuO nanocomposites for detection and quantification of PMMA bone cement degradation at trace levels

Polymethyl methacrylate (PMMA) bone cement is a popular bone-filling material for biomedical applications. Bone-cement implant failure is a common occurrence, but the consequence of this failure can be prevented/minimised by early detection of degradation. This work utilises a stable isotope labelling approach to monitor PMMA bone cement degradation. Stable isotopically enriched traceable nanoparticles of ⁶⁵CuO were synthesized and introduced to PMMA bone cement. Accelerated and normal degradation of ⁶⁵CuO-loaded PMMA bone cement nanocomposite was performed in acetone and simulated body fluid (SBF). ⁶⁵Cu was detected and quantified upon PMMA bone cement nanocomposite degradation. The results showed a linear correlation between bone cement degradation and tracer release. When the ⁶⁵CuO-PMMA composite deteriorated by 6.10 ± 3.04% in acetone, 5.6 ± 2.5 µg of tracer was released in 10 min. Similarly, after one week of degradation in SBF, 0.35 ± 0.31 µg of ⁶⁵Cu tracer was released, translating to a 0.18 ± 0.09% weight loss. The stable isotopic tracer approach allowed us to measure and detect ⁶⁵Cu under conditions of high background Cu concentration present in the human body upon 0.2% of PMMA nanocomposite degradation. ⁶⁵CuO nanoparticles addition to PMMA bone cement did not alter the cytocompatibility (proliferation, differentiation, and osteocalcin formation) in MG-63 cells.