The MatNaBio Group consists out of ambitious young researchers with a wide experience in the synthesis and functionalization of nanoparticles (NPs) for biological applications, primary for bioimaging but also for therapeutic applications or even a simultaneous combination of both of these applications (theranostics). The group is very active in the synthesis of specifically shape-tuned metallic (gold) and bimetallic (Au@Ag) NPs with plasmonic properties, dielectric NPs such as those based on NaYF₄ or NaGdF₄ with upconverting properties (upconverting nanoparticles, UCNP) as well as semiconductor NPs like Ag₂S, PbS, BiS CdSe@ZnS with near-infrared (NIR) emitting properties. Besides their synthesis, the MatNaBio group also possesses the know-how to functionalize the NP’s surface with biologically relevant ligands, depending on the aimed biomedical application, yet maintaining the colloidal stability of the NPs. The colloidal materials have been successfully used for multiple biological applications in the frame of different national and international projects in which the MatNaBio group participated. More precisely, their applications range from highly sensitive in vitro sensors of specific pathogens, over the targeted diagnosis of a specific tissue in vivo to the on-demand liberation of pharmacologically active compounds. These applications have required their functionalization with biological molecules like antibodies, antigens, peptides as well as DNA/RNA sequences, but also with pharmacologically active compounds connected to an on-demand cleavable linker or with compounds that ensure their colloidal stability in aqueous solutions, prompting the group to create new functionalization routes to tailor the NPs to the biological requirements.