Self-assembling nanoparticle could aid cancer diagnosis

A new self-assembling nanoparticle which targets cancerous tumours could boost the effectiveness of MRI scanning to help doctors diagnose the disease earlier. The iron oxide nanoparticles (IONPs), developed at Imperial College London, are designed to selectively undergo copper-free click conjugation upon sensing matrix metalloproteinase (MMP) enzymes. In this chemical reaction, the nanoparticles interact with the cell, shed their special protein coating and ‘click’ together to form a superparamagnetic nanocluster network capable of being seen on the scan. “By improving the sensitivity of an MRI examination, our aim is to help doctors spot something that might be cancerous much more quickly,” said Professor Nicholas Long from the Department of Chemistry. “This would enable patient to receive effective treatment sooner, which would hopefully improve survival rates from cancer.” The Angewandte Chemie study used cancer cells and mouse models to compare commonly used imaging agents in MRI scanning against the effect of these new self-assembling nanoparticles; the latter produced a more powerful signal and created a clearer MRI image of the tumour. Before testing and injecting the non-toxic nanoparticle into mouse models, researchers had to be sure it would not become so large during self-assembly that it would cause damage. The nanoparticle was injected into a saline solution in a petri dish and monitored for four hours; it grew from 100 to 800nm, remaining small enough not to cause damage. The scientists are now working on improving the effectiveness of their design, and hope to test it in a human trial within the next three to five years. Dr Juan Gallo from the Department of Surgery and Cancer said: "We're now looking at fine tuning the size of the final nanoparticle so that it is even smaller but still gives an enhanced MRI image. If it is too small the body will just secrete it out before imaging, but too big and it could be harmful to the body. Getting it just right is really important before moving to a human trial." “We’re now trying to add an extra optical signal so that the nanoparticle would light up with a luminescent probe once it had found its target, so combined with the between MRI signal it will make even easier to identify tumours,” Long added. CXCR4-targeted and MMP-Responsive Iron oxide nanoparticles for enhanced magnetic resonance imaging