Preparation and Biocompatibility Evaluation of Nanoscale Isoniazide-Loaded Mineralized Collagen Implants for Tuberculous Bone and Joint Repair

Bone and joint tuberculosis is an extremely severe infectious disease that commonly occurs due to the primary infection of a type of mycobacteria, called Mycobacterium tuberculosis. Under the current scenario, there are very limited supplies of bone grafts available for the treatment of deceased bone, including autogenous bone and synthetic biomaterials. The present study aimed to construct a nanoscale isoniazid-loaded mineralized collagen implant, and then to explore its physicochemical properties and to investigate its biocompatibility suitable for bone and joint repair. Using type I collagen as raw material and the principle of biomimetic mineralization for self-assembly of bone tissue, a new drug-loaded mineralized collagen implant was constructed by molecular coprecipitation with isoniazid. Its surface morphology, elemental composition, and porosity were characterized by field emission scanning electron microscope (SEM), X-ray diffraction (XRD), and pycnometer. The performance of the implant was gauged by sustained release and degradation, which were studied using an ultraviolet spectrophotometer and a simulated in vivo environment. The drug loading and encapsulation rates of the implants were (6.25 ± 0.48)% and (54 ± 2.34)%, respectively. The in vitro release time of the scaffold was more than 12 weeks and the degradation performance was excellent. The scaffold was then implanted into mice, and the inflammatory reaction of local tissue was observed by Haemotoxylin and Eosin (H&E) and Masson. The in vivo evaluation in mice showed that the scaffold was biocompatible. Overall, compared with traditional drug loading systems, the isoniazid biomimetic mineralized collagen implant constructed here has better drug release performance, biodegradability, and biocompatibility. This kind of collagen implant may find potential applications in tuberculous bone and joint repair.