Gelatin/gentamicin sulfate-modified PMMA bone cement with proper mechanical properties and high antibacterial ability

Abstract

With the aging of the population, the risk of osteoporotic vertebral compression fractures (OVCF) caused by osteoporosis increases rapidly. Surgeons often fill the bone defect with injectable polymethylmethacrylate (PMMA) bone cement through vertebroplasty. However, compared with cancellous bone, the higher mechanical properties of PMMA bone cement can easily lead to the fracture of the adjacent cone. Besides, the wound infection caused by surgery is also a serious problem. In order to solve these problems, we designed a new type of PMMA bone cement, by adding gelatin as a pore former, 5% (w/w) gentamicin sulfate (GS) for antibacterial purpose, and 30% (w/w) barium sulfate (BaSO4) to provide excellent radiopacity. Compared with the traditional PMMA bone cement, with the dissolution of gelatin after being immersed in phosphate buffered saline (PBS) for 14 d, the mechanical properties of modified PMMA bone cement decreased by approximately 67%, which is close to the human cancellous bone. Besides, the release of GS increased 3.8 times, and the GS concentration remained above the minimum inhibitory concentration (MIC) for 12 d. In addition, the setting properties, contact angle, antibacterial ability, and cell compatibility of PMMA bone cement also maintained well. The integration and dissolution of gelatin were observed by a scanning electron microscope (SEM). All results indicate that the new type of gelatin-modified PMMA bone cement is a potential candidate material for vertebroplasty.