Molecular diffusion in polyelectrolyte multilayers Research on novel and advanced biomaterials is an indispensable step towards their applications in desirable fields such as tissue engineering regenerative medicine cell culture or biotechnology. The work presented here focuses on such a promising material: polyelectrolyte multilayer (PEM) composed of hyaluronic acid (HA) and poly(L lysine) (PLL). This gel like polymer surface coating is able to accumulate (bio )molecules such as proteins or drugs and release them in a controlled manner. It serves as a mimic of the extracellular matrix (ECM) in composition and intrinsic properties. These qualities make the HA PLL multilayers a promising candidate for multiple bio applications such as those mentioned above. The work presented aims at the development of a straightforward approach for assessment of multi fractional diffusion in multilayers (first part) and at control of local molecular transport into or from the multilayers by laser light trigger (second part). The mechanism of the loading and release is governed by the interaction ...