• Interaction of AuNPs, AgNPs and PtNPs with human serum formed a protein corona. • The protein corona formation depends on the core material composition and its size. • Proteins with different functionality were detected in all protein coronas. Adsorption of biomolecules onto nanoparticles surface in biological samples led to the formation of a bio-corona, it could modified the "identity" of nanoparticles, contributing to the determination of their toxicity and biocompatibility. Gel electrophoresis in combination with liquid chromatography-tandem mass spectrometry (LC–MS/MS) was employed to qualitatively analyze and identify the human serum proteins adsorbed on the surface of three different nanomaterials stabilized with citrate: 10.02 ± 0.91 nm gold nanoparticles (AuNPs), 9.73 ± 1.70 nm silver nanoparticles (AgNPs) and, 2.40 ± 0.30 nm platinum nanoparticles (PtNPs). An exhaustive analysis and classification of all identified proteins related with their function were also developed. [ABSTRACT FROM AUTHOR]