Three kinds of magnetic nanoparticle, tetraheptylammonium capped nanoparticles of Fe3O4, Fe2O3 and Ni have been synthesized, and the synergistic effect of these nanoparticles on the drug accumulation of the anticancer drug daunorubicin in leukaemia cells has been explored. Our observations indicate that the enhancement effect of Fe3O4 nanoparticles is much stronger than that of Fe2O3 and Ni nanoparticles, suggesting that nanoparticle surface chemistry and size as well as the unique properties of the magnetic nanoparticles themselves may contribute to the synergistic enhanced effect of the drug uptake of targeted cancer cells.

Asymmetrical deformation of an aqueous electrolyte droplet bridging two bipyridinium-modified Au-electrodes is achieved upon the application of voltages resulting in the selective reduction and oxidation of the bipyridinium units on the two electrodes. The different contact angles at the right and left sides of the droplet originate from the electrochemically controlled changes of the wetting properties of the modified electrodes. The reversible and repeatable formation of an electrolytic contact between a side Ptwire electrode and the respective bottom Au-electrode is controlled by the voltage applied between the two bottom Au-electrodes.

The electrochemical redox-induced contact angle changes of hemoglobin droplets in the absence and presence of tetraheptylammonium-capped Fe3O4 nanoparticles have been explored by using in situ electrochemical contact angle measurements. The results indicate that the electrochemical redox process may lead to some structure changes of hemoglobin (Hb), which could further induce the hydrophobic-to-hydrophilic changes of the relative droplets. Our observations demonstrate that hemoglobin could self-assemble on the surface of the functionalized Fe3O4 nanoparticles as Hb–Fe3O4 nanocomposites, which may contribute to much more significant change of the electrochemical redox-induced contact angle values than that with free nano-Fe3O4. These results suggest that in situ electrochemical contact angle measurements could be readily applied as a new and convenient method to detect some specific biological process.

The biomolecular binding behavior of anticancer drug dacarbazine (DTIC) in the presence of titanium dioxide (TiO2) nanoparticle interface has been studied by using electrochemical methods. The results indicate that the presence of TiO2 nanoparticles can obviously increase the binding affinity of DTIC to DNA or DNA bases and significantly enhance the detection sensitivity for the relative biomolecular recognition.

In situ electrochemical static contact angle measurements are employed to probe photoinduced electron transfer processes at electrode surfaces. Photosystems consisting of tris(2,20-bipyridyl)ruthenium(II), (Ru(bpy)32+), N,N0-dimethyl-4,40-bipyridinium (MV2+), Na2EDTA or CdS nanoparticles, MV2+, triethanolamine (TEOA) were included in aqueous droplets that were coupled with a ferrocene monolayer-functionalized electrode. Upon the oxidation of the interface (0.5 V vs. Ag quasi-reference electrode), and the illumination of the systems, photoinduced electron transfer to the modified electrode proceeds. The electron transfer processes yield photocurrents, and the photoelectrochemical transformations are followed by contact angle measurements. Similarly, a CdS/bipyridinium monolayer is assembled on an Au electrode support. The redox transformations of the bipyridinium units control the hydrophilic/hydrophobic properties of the interface, and are followed by contact angle analyses. Irradiation of the CdS/bipyridinium layer associated with the electrode biased at -0.3 V yields a photocurrent. The changes in the wetting properties of the irradiated interface are investigated by contact angle measurements.