Biological fluids contain a plethora of different components that can coat nanoparticle's surface and critically affect their interaction with living systems. The recent literature has focused efforts on understanding the overall protein role in this nanoparticle's coating (commonly called a protein corona) without considering other components’ influence. Here, we report a protocol to study the relationship between biological fluid components excluding proteins (referred to as a biomolecular corona) and nanoparticles. For this purpose, functionalized silica nanoparticles were duly synthesized to experimentally investigate the extent of biomolecular corona adsorption over different surfaces. This adsorption was directly correlated with the silica surface chemical constitution, while the extent of biomolecular corona coating affected the overall surface charge and the colloidal stability of the functionalized nanoparticles. In addition, the bactericidal properties of biomolecular corona-coated nanoparticles were tested against two medically relevant bacteria (Escherichia coli and Staphylococcus aureus). Biological results indicated that the presence and the extent of the biomolecular corona affect the bactericidal properties of the nanoparticles.