Layer-by-layer (LBL) assembly of functionalized nanoparticles (FNPs) within a polyelectrolyte network is described (see image). The LBL-NP-assembly-based modification can be used to engineer surfaces with multiple functions such as controlled (multiple-) drug release with distinct release kinetics and enhanced contrast in clinical imaging modalities. This novel surface modification strategy is expected to accelerate the development of bioresponsive coatings for implantable biomedical devices.