After uptake by U87 MG and A375 cancer cells, cobaltabisdicarbollide [COSAN] distributes between membrane and nucleus and presents no relevant cytotoxicity against both cell lines even for long incubation times. The cytotoxicity of Na[COSAN] was also tested towards one normal cell line, the V79 fibroblasts, in order to ascertain the noncytotoxic profile of the compound. As the cell's nucleus contains DNA, the interaction between [COSAN] and double-stranded calf thymus DNA (CT-dsDNA) has been investigated. There is a strong interaction between both molecules forming a nanohybrid CT-dsDNA-[COSAN] biomaterial, which was fully characterized. Moreover, Na[COSAN] shows characteristic redox peaks ascribed to the oxidation/reduction of Co at a formal potential of -1.444 V and it can be accumulated at a surface-immobilized DNA layer of glassy carbon electrodes. The equilibrium surface-binding constants (K /K ), which confirm that [COSAN] interacts with DNA by an intercalative or electrostatic mode, depending on the ionic strength of the solution, were estimated. In addition, high binding affinity of Na[COSAN] to proteins was observed by B{ H} NMR and confirmed in vivo. Finally, biodistribution studies of [COSAN] in normal mice were run. After administration, Na[COSAN] was distributed into many organs but mainly accumulated in the reticuloendothelial system (RES), including liver and spleen. After 1 h, the formation of aggregates by plasma protein interaction plays a role in the biodistribution profile; the aggregates accumulate mostly in the lungs. Na[COSAN], which displays low toxicity and high uptake by relevant cancer cells accumulating boron within the nucleus, could act as a suitable compound for further developments as boron neutron capture therapy (BNCT) agents.

A label-free DNA and single nucleotide polymorphism (SNP) sensing method is described. It is based on the use of the pseudodielectric function of gallium plasmonic nanoparticles (GaNPs) deposited on Si (100) substrates under reversal of the polarization handedness condition. Under this condition, the pseudodielectric function is extremely sensitive to changes in the surrounding medium of the nanoparticle surface providing an excellent sensing platform competitive to conventional surface plasmon resonance. DNA sensing has been carried out by immobilizing a thiolated capture probe sequence from Helicobacter pylori onto GaNP/Si substrates; complementary target sequences of Helicobacter pylori can be quantified over the range of 10 pM to 3.0 nM with a detection limit of 6.0 pM and a linear correlation coefficient of R(2) = 0.990. The selectivity of the device allows the detection of a single nucleotide polymorphism (SNP) in a specific sequence of Helicobacter pylori, without the need for a hybridization suppressor in solution such as formamide. Furthermore, it also allows the detection of this sequence in the presence of other pathogens, such as Escherichia coli in the sample. The broad applicability of the system was demonstrated by the detection of a specific gene mutation directly associated with cystic fibrosis in large genomic DNA isolated from blood cells.

The electrochemical behaviour of metallocarborane sodium salts and their interactions with DNA have been studied. They are shown to be selective redox indicators with wide-ranging potential as electrochemical indicators in DNA biosensors.