An aqueous cell culture medium composition includes an aqueous cell culture solution configured to support the culture of mammalian cells. The composition further includes a synthetic polymer conjugated to a polypeptide dissolved in the aqueous cell culture solution. The synthetic polymer conjugated to a polypeptide is configured to attach to the surface of a cell culture article under cell culture conditions. Incubation of the aqueous cell culture medium composition on a cell culture surface under cell culture conditions results is attachment to the surface of the synthetic polymer conjugated to the polypeptide.