An intraocular dye solution based on lutein and zeaxanthin in a surrogate internal limiting membrane model: a Langmuir monolayer study. Investigating the role of biomolecules and bioactive molecules associated with membranes is fundamental to comprehend at the molecular point-of-view biochemical and clinical processes that occur at biointerfaces. In this paper we exploit the interaction of an intraocular dye solution based on lutein and zeaxanthin in surrogate internal limiting membrane (ILM) models, consisting of dipalmitoyphosphatidylcholine (DPPC) Langmuir monolayers, pure or mixed with collagen, proteoglycan and laminin. The interactions between the film components occurring at the air-water interface were investigated with surface pressure-area isotherms and polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS). A natural dye solution based on lutein and zeaxanthin, employed to label ILM in ophthalmic surgery, was incorporated in the ILM model, and the data suggested non-rupture of the structure of the membrane, with predominance of interactions based on intermolecular forces.