Counterion Effects on Nano-confined Metal-Drug-DNA Complexes
  We have explored morphology of DNA molecules bound with Cu-complexes of piroxicam molecules, a non-steroidal anti-inflammatory drug (NSAID), under one-dimensional confinement of thin films and have studied the effect of counterions present in a buffer. X-ray reflectivity at and away from the Cu K absorption edge and atomic force microscopy studies reveal that confinement segregates the drug molecules preferentially in a top layer of the DNA film, and counterions enhance this segregation. 
Nupur Biswas, Sreeja Chakraborty, Alokmay Datta, Munna Sarkar, Mrinmay   K. Mukhopadhyay, Mrinal K. Bera and Hideki Seto
cond-mat.soft cond-mat.mes-hall physics.bio-ph