Partitioning of doxorubicin into Langmuir and Langmuir–Blodgett biomimetic mixed monolayers: Electrochemical and spectroscopic studies

• We investigated partitioning of doxorubicin through mixed biomimetic monolayers.
• Biomimetic monolayers were formed by Langmuir and Langmuir–Blodgett techniques.
• We monitored the drug interactions with different regions of biomimicking films.
• The drug adsorbs easily on the hydrophilic part of a monolayer.
• The organization of hydrophobic part controls the rate and amount of partitioning.

The partitioning of doxorubicin, a potent anticancer drug, was examined in relation to the composition and structural properties of the biomimetic molecular films. We have systematically studied the passive permeation of doxorubicin across the two-component monolayers of different organization, following the drug interactions with the hydrophilic part of the monolayer and then, with its hydrophobic moiety, separately. We investigated independently these two types of the interactions, likely competing in a native membrane, respectively for the Langmuir monolayers on an aqueous subphase and for Langmuir–Blodgett monolayers on gold, exposed to the drug in an aqueous solution. This gave us a unique possibility to monitor the drug interactions with different regions of biomimicking film. The overall picture emerging from these results suggests that the hydrophobicity of monolayer interior allows for the penetration and accumulation of the drug, while its organization controls the rate and amount of doxorubicin molecules through such films.