An article suitable for inducing quasispherical cell clustering is provided. The article comprising: a layer suitable for culturing quasispherical cell clusters, the layer comprising a bulk region comprising an interpenetrating network of at least one predominantly positively charged polyelectrolyte and at least one predominantly negatively charged positive polyelectrolyte, a back surface region, and a front surface region, wherein the front surface region comprises a net negative fixed surface charge density of between about 0.4 micromole per m2 and about 1.5 micromole per m2.