We present a rapid synthetic method for the development of hyperbranched PEIs decorated with different oligosaccharide architectures as carrier systems (CS) for drugs and bioactive molecules for in vitro and in vivo experiments. Reductive amination of hyperbranched PEI with readily available oligosaccharides results in sugar functionalized PEI cores with oligosaccharide shells of different densities. These core−shell architectures were characterized by NMR spectroscopy, elemental analysis, SLS, DLS, IR, and polyelectrolyte titration experiments. ATP complexation of theses polycations was examined by isothermal titration calorimetry to evaluate the binding energy and ATP/CS complexation ratios under physiological conditions. In vitro experiments showed an enhanced cellular uptake of ATP/CS complexes compared to those of the free ATP molecules. The results arise to initiate further noncovalent complexation studies of pharmacologically relevant molecules that may lead to the development of therapeutics based on this polymeric delivery platform.