Bioglass nanoparticles to fix our bones
Julian Jones is an expert in bioactive glass, a material able to stimulate bone regeneration. Professor of Biomaterials at the Imperial College London, he has devoted a substantial part of his career to better understanding the properties of this material. But it was back in 2015 that a particular encounter considerably boosted his research: He and his team crossed paths with Alessandra Pinna, who was looking into the antioxidant properties of tiny particles of cerium oxide called nanoceria. Prof Jones had been following the fate of bioactive nanoparticles inside cells with bioimaging specialist Alexandra Porter. Together, the three scientists were quick to realise the potential of combining the two nanoparticles for treating osteoporosis, and decided to kick start a dedicated project under the acronym INTO (Inorganic therapeutic nanoparticles for osteoporosis). “At the time, we were developing porous bioglass implants able to release strontium ions if a patient had a large hole in their bone. But in most cases, patients with osteoporosis do not have such holes: their bone is low in density, with a high risk of fracture, and an injectable or oral therapy was required,” Prof Jones recalls. “Our exisiting nanoparticles were already taken up by all cells into their cytoplasm. They could biodegrade within the cells, releasing strontium ions that can stimulate bone forming cells (osteoblasts) and inhibit bone degradation (osteoclasts) activity. By adding nanoceria to the mix, we can now also clean up free radicals and further improve the bone loss prevention”. The development process consists of two main tasks: synthesising biodegradable mesoporous silica nanoparticles by sol-gel, and creating the nanoceria by co-precipitation method and microwave treatment before entrapping it within the silica network. Over the course of the project, the team exposed the new devices to different types of bone cells and bone marrow stem cells. The results demonstrate that INTO’s particles are capable both of promoting osteogenesis and scavenging free radicals (reactive oxidative species). A threshold dose has also been determined, below which cells can benefit from the nanoparticles’ antioxidant and osteogenesis activity without being damaged. The resulting treatment is a combination that has potential for osteoporosis – the particles may strengthen osteoporotic bones by stimulating natural regeneration mechanisms, reducing osteoporotic fractures and improving mobility and quality of life for millions of patients, according to Prof Jones – but also for other diseases. “We have promising results in encouraging nerve cells to grow (neurite outgrowth), so if we can get our tiny particles to cross the blood-brain barrier, they could be used in treatment for Parkinson’s Disease. We also have nanoparticles that have some success in killing cancer cells without harming healthy cells. The nanoceria could work in synergy with our nanoparticles to widen the dose window in which our nanoparticles would be effective,” Prof Jones enthuses. The next step is, of course, preclinical trials. Prof Jones and his team have already applied for further funding to explore the potential of their nanoparticles for Parkinson’s disease treatment, and they are putting together a large collaborative proposal on cancer treatment and bio-imaging (combination of mesoporous particles with gold for early diagnosis of cancer) particles, looking towards the next stage of translating the technology towards the clinic. Their objective: finding out whether active targeting of specific cancer cells can improve the delivery of the nanoparticles.
Keywords
INTO, osteoporosis, bioglass, nanoceria, nanotechnology, bone, implant
