French researchers have developed a self-setting injectable macroporous foam for repairing bone and assisting its growth. It could help regenerate bone faster than other materials while offering a quick and minimally invasive way for surgeons to perform bone repair procedures, and possibly treat osteoporosis.
With 70% of bone consisting of a calcium phosphate mineral called hydroxyapatite, calcium phosphate cements (CPCs) are widely used in surgery as bone substitutes. CPCs have excellent properties for the job – they are injectable, biocompatible, self-setting and microporous allowing nutrients to flow throughout the implant site, which assists bone regeneration.
However, it’s been a challenge introducing macroporosity into such injectable CPCs, which is desirable to facilitate quicker bone regeneration and reinforce cancellous bone; the flexible and spongy tissue that degenerates with osteoporosis. Macroporous CPCs do exist but those that are injectable have poor mechanical properties.
Now Pierre Weiss and colleagues at the University of Nantes have created a macroporous self-setting CPC in the form of an injectable foam by using a silanised-hydroxypropyl methylcellulose (Si-HPMC) hydrogel as a foaming agent. ‘Our approach is simple and gives us really good results in terms of mechanical properties and macroporous structures,’ says Weiss.