AIM:To study the inhibition of p21cip1 gene on proliferation of cultured human retinal pigment epithelial(RPE) cells by application of nano-technology.METHODS:Preparation of p21cip1 gene nano-particles was transfected into cultured human RPE cells for detection of expression of p21cip1by immunohistochemistry.Cell cycle related cell volume changes were detected by flow cytometry.RESULTS:DNA content of p21cip1 nano-particles was 3%,encapsulation efficiency was 78%.Because of the protective effects of PLGA-PVA vector p21cip1 gene in the body could maintain a longer valid period than naked plasmid,overcoming problems of the naked plasmid prone to nuclease degradation in vivo.Flow cytometry results showed RPE cells of transfected object gene had G1 phase arrest,significantly inhibited cell proliferation.Immunohistochemical detection results showed RPE cells of transfected object gene had markedly stronger expression of p21cip1.CONCLUSION:p21cip1 gene may serve as a target gene,with the emerging nano-particles of gene vector,to be used for gene therapy in inhibition of cell proliferation.