For the comparison in different sericin extraction methods, cells cultured on urea extracted sericin films demonstrated highest proliferation rate. Moreover, proliferation rate of cells cultured on urea extracted sericin films was faster than that of cells cultured on the blended silk fibroin/sericin films. This confirmed that urea extracted sericin film could enhance proliferation rate of L929 mouse fibroblasts. Thus, urea treatment was suggested as another potential method for sericin extraction