Abstract: Methods of performing an assay for biomolecules and solid supports for use in such assays are disclosed. An activated polymeric material is used as a solid support for binding biomolecules. In a preferred form, the support is made of a generally hydrophobic, nonporous polymer which has been activated by treatment with solvents or by mechanical means to enhance the binding characteristics of the support. The support can be made of a copolymer, such as a copolymer of polystyrene and polybutadiene. Detection of bound biomolecules is preferably performed by means of staining reactions and gray level scanning. Emulsifying agents, such as detergents, can be applied to the surface of the support to substantially inhibit additional materials from being bound to the support.