Soares da Costa D., Pires R. A., Frias A. M., Reis R. L., and Pashkuleva I.,  "Sulphonic groups induce formation of filopodia in mesenchymal stem cells",  Journal of Materials Chemistry, vol. 22, issue 15, pp. 7172-7178, doi:10.1039/C2JM15762D, 2012.