SiO2 microspheres with natural hydroxyl or silanol (SiOH) surface groups for adsorption of nucleic acids, cells, or antibodies with low nonspecific binding. Non-functionalized silica microspheres are available as ~10% solids (w/w) aqueous suspensions or in dry form in these standard amounts: 0.5, 1.0, 1.5, and 5.0 g.