Rational design of gold nanoparticles functionalized with carboranes for application in Boron Neutron Capture Therapy

In this paper we propose a bottom-up approach to obtain new boron carriers built with ortho-carborane functionalized gold nanoparticles (GNPs) for applications in Boron Neutron Capture Therapy. The interaction between carboranes and the gold surface was assured by one or two SH-groups directly linked to the boron atoms of the B₁₀C₂ cage. This allowed obtaining stable, nontoxic systems, though optimal biological performance was hampered by low solubility in aqueous media. To improve cell uptake, the hydrophilic character of carborane functionalized GNPs was enhanced by further coverage with an appropriately tailored diblock copolymer (PEO-b-PCL). This polymer also contained pendant carboranes to provide anchoring to the pre-functionalized GNPs. In vitro tests, carried out on osteosarcoma cells, showed that the final vectors possessed excellent biocompatibility joint to the capacity of concentrating boron atoms in the target, which is encouraging evidenced to pursue applications in vivo.