The antiviral active boron cluster [3-cobalt bis(1,2-dicarbollide)](-1) anion, CoD, interacts and forms a stable complex with one of the most widely used polymeric component of drug delivery systems: poly(ethylene oxide), PEO. The formation of insoluble NaCoD/PEO complex can be exploited in design of water-soluble metallacarborane-containing nanoparticles that could offer applications in medicine.
We studied the boron cluster interaction with a hydrophilic block copolymer: poly(ethylene oxide)-block-poly(methacrylic acid), PEO-PMA. The interaction leads to a spontaneous formation of core-shell nanoparticles.
The insoluble core contains the PEO/CoD complex, while the polyanionic PMA blocks, which do not interact with the metallacarborane, form the pH-responsive micellar shell and stabilize the particles in aqueous media.