A cell culture article includes a substrate having a polymer coating that is conducive to colony passaging of cells cultured on the coating. Example polymer coatings are formed from polygalacturonic acid (PGA), alginate, or combinations thereof. Cells cultured on the polymer coating can be separated from the substrate as a colony or layer of cells by exposing the polymer coating to (i) a chelating agent, (ii) a proteinase-free enzyme, or (iii) a chelating agent and a proteinase-free enzyme.