Bone consists of 70% of a calcium phosphate mineral called hydroxyapatite. Calcium phosphate cements (CPCs) are used in surgery as a bone substitute. They are injectable, biocompatible, self-setting, and microporous (allowing nutrients to flow and assist in bone regeneration). Macroporosity has been hard to create with an injectable CPC, which enables quick bone regeneration and reinforce the flexible tissue that is lost with osteoporosis.
French researchers have recently accomplished this. They created a macroporous, self-setting CPC in the form of an injectable foam using a silanised-hydroxypropyl methylcellulose (Si-HPMC) hydrogel as a foaming agent. The results are promising.
Their initial attempts to improve CPC by adding the hydrogel lowered the pH of the solution and created air bubbles in the mixture, which were impossible to remove. With the improved procedure, Si-HPMC and CPC are put in separate syringes, then air is pumped into the CPC syringe and the two are plunged together with a connector, adding air and creating a foam. The foam was tested on rabbits with no toxic effects and new bone growth.
This foam could be an effective material for treating bone defects, diseases, and osteoporosis. As research progresses, this new foam can give surgeons an easy material to use for minimally invasive procedures.
Watch this short video about how the foam works:
Urquhart, James. “Injectable foam repairs bones.” Research. Chemistry World, 22 Dec 2015. Web. 24 Jan 2016.