Assessment of radiation damage in hydroxyapatite and its mitigation through N-acetylcysteine modification

Reliable bone graft substitutes play a vital role in addressing the global burden of skeletal injuries and diseases. Synthetic bone mimics containing hydroxyapatite (HAP) serve as favourable alternatives to autografts and allografts, since HAP is the primary mineral component in natural bone tissue. However, standard sterilization by high-energy ionizing radiation generates free radicals that damage HAP on a molecular scale and compromise its integrity as a functional bone graft material. This study investigated N-acetylcysteine (NAC) as a radioprotective modifier for synthetic HAP. Pure and NAC-modified HAP were exposed to a series of X-ray doses using a clinical linear accelerator. Raman spectroscopy and powder X-ray diffraction (PXRD) were then used to evaluate radiation-induced structural degradation. These findings will inform the development of synthetic bone materials capable of withstanding the high-energy flux of radiation processing, ultimately improving the outcomes of bone reconstruction procedures.