Abstract: Objective To construct targeted drug carriers with anti-human epidermal growth factor receptor 2(anti-HER2) and doxorubicin,and to determine its anti-tumor effects in vitro.Methods Doxorubicin nanoparticles (DNPs) loaded with doxorubicin were prepared by using doable emulsion method,and their appearance,distribution characteristics of diameter,Zeta potential and in vitro drug release were asscsscd.Immunonanoparticles (INPs) were then formed by using coupling agents that combined DNPs with trastuzumab (Herceptin),the human anti-HER2 antibody.The immunologic activity was determined via enzyme-linked immunosorbent assay (ELISA),and anti-tumour effects on SKBR3,the tumor cells with intense HER2 expression,via MTT method.Results The constructed nanoparticles appeared spherical or para-spherical,with a mean diameter of ( 198.2± 12.4) nm,Zeta potential of-41 mV,encapsulation ratio of 68.6% and 96-hour in vitro drug release of 50%,respectively.INPs were shown to be immunologically active to SKBR3 and SKOV3 tumor ceils,but not MCF-7,as indicated by ELISA.Additionally,comparison on SKBR3 snrvival rate suggested that INPs conferred remarkably higher tumor cell inhibitory effects than DNPs and doxorubicin (both P<0.05 ).Conclusion The immunologic activity and targeting characteristics of IN Ps may result in effective inhibition of the growth of tumor cells with highly spccialized HER2 cxpression.