Antibody-based imaging of a particularly aggressive form of breast cancer is undergoing clinical trials worldwide, but the path from trial to application is being hampered by a major obstacle: safety.

Concerns stem from inefficient tumor targeting, which can result in accumulation in the bone marrow, liver and kidneys of the radioactive material necessary for the imaging. Recent efforts have focused on nanoscale delivery vehicles with immune components, but these vehicles are often still too large (20 nanometers or larger) for renal clearance after imaging.

Ulrich Wiesner, the Spencer T. Olin Professor of Engineering in materials science and engineering, in collaboration with Dr. Michelle Bradbury of Memorial Sloan Kettering Cancer Center (MSKCC) and Weill Cornell Medicine, has proposed a novel approach using ultrasmall silica nanoparticles – better known as “Cornell dots” (or C dots) – invented in his lab more than a dozen years ago.

Their team – including researchers at pharmaceutical company MedImmune – have equipped the C dots with antibody fragments. Because the resulting conjugates are smaller than 8 nanometers, these C dots allow for renal clearance while achieving the specificity needed for efficient tumor targeting.
They report their discovery in Nature Communications (“Ultrasmall Targeted Nanoparticles with Engineered Antibody Fragments for Imaging Detection of HER2-Overexpressing Breast Cancer“). Feng Chen, senior research scientist at MSKCC, and Kai Ma, postdoctoral researcher in the Wiesner lab, are co-lead authors.