A chromatographic media for separating bio-polymers, the chromatographic media having cationic exchange properties and anionic exchange properties, the chromatographic media comprising: (a) non-porous substrate particles including an organic polymer, the substrate particles having a neutral hydrophilic layer at a surface of the non-porous substrate particles, in which the neutral hydrophilic layer is configured to reduce a binding of the bio-polymers directly to the non-porous substrate particles compared to a binding of the bio-polymer to the non-porous substrate particles without the neutral hydrophilic layer; (b) a charged first ion exchange layer bound to the substrate particles on top of the hydrophilic layer, the first ion exchange layer comprising first ion exchange groups; and (c) a charged second ion exchange layer bound to the substrate particles on top of the first ion exchange layer.