Microcarriers, matrices and scaffolds for growing mammalian cells are provided which include copolymer particles and matrices comprising of polysaccharide-polyamine copolymers. The copolymeric particles and matrices have a pore size of at least 50 microns and permit the mammalian cells to grow both on an exterior surface of the particles and matrices and within an interior of the particles and matrices. Methods for making such microcarriers, matrices and scaffolds, and compositions are also provided. Methods for growing mammalian cells utilizing such microcarriers, matrices and scaffolds and compositions are also provided.