After confirming the possibility of enzyme-triggered degradation of the herein developed peptide-cross-linked nanogels using a disease-relevant enzyme of the MMP class, loading and release properties of a model protein cargo (fluorescent Oregon Green-labelled bovine serum albumin, OG-BSA) was studied using one selected copolymer (5a4). UV-Vis spectroscopy revealed a loading efficiency of 18 ± 8 % (average ± SD of three independent batches) after purification by size exclusion chromatography. This represents better loading efficiencies for nanogels compared to polymersomes made via standard film rehydration, that often have low loading efficiencies of few percent for hydrophilic cargo such as proteins. Our rapid procedure to yield protein-loaded, well-defined nanogels at high polymer concentrations without the use of any organic solvent represents a suitable strategy to load sensitive therapeutic proteins for biomedical applications in the future. Loading and release of our model protein OG-BSA was further studied in detail by FCS (Figure ). Successful loading of OG-BSA into peptide cross-linked 5a4 nanogels was observed by FCS.