目的 检测肝细胞靶向性半乳糖基化聚乙烯亚胺衍生物Gal-Bu对大鼠肝细胞（BRL-3A）的转染效率。方法 对PEI-Bu化学修饰以半乳糖基团制备Gal-Bu，琼脂糖凝胶电泳检测其复合质粒DNA的能力；MTT法检测Gal-Bu对BRL-3A的细胞毒性；以荧光素酶质粒作为报告基因，测定Gal-Bu在BRL-3A细胞的转染效率；半乳糖竞争抑制实验观察Gal-Bu对肝细胞的靶向性。结果 琼脂糖凝胶电泳表明在质量比＞15时，Gal-Bu具有复合DNA的能力。在5~100 μg/mL浓度范围内，Gal-Bu和PEI 25 000的细胞毒性随浓度升高而增大；在同一浓度下，Gal-Bu的细胞毒性小于PEI 25 000（P<0.01）。Gal-Bu/DNA在质量比为50时达到最高转染活性，其数值为PEI 25 000的5.6倍（P<0.01），且接近Lipofectamine 2000。半乳糖竞争抑制实验表明，100 mmol/L的半乳糖可显著降低Gal-Bu的转染效率（P<0.01），但是并不影响PEI-Bu的转染效率（P>0.05）。结论 Gal-Bu是一种低细胞毒性、高转染活性的非病毒肝细胞靶向基因载体，在肝脏疾病的基因治疗领域中具有潜在的应用前景。

Objective To evaluate the transfection efficiency of hepatocyte-targeting galactosylated polyethylenimine derivative Gal-Bu in rat liver cells (BRL-3A). Methods Gal-Bu was synthesized through chemical modification of PEI-Bu with galactose residue. The pDNA condensation ability of the polymer was evaluated by agarose gel electrophoresis, MTT assay was employed to detect the cytotoxicity of the polymer in BRL-3A cells, luciferase plasmid was used as the reporter gene to determine the transfection efficiency of Gal-Bu in BRL-3A cells, and competition assay of galactose was performed to investigate the hepatocyte-targeting property of Gal-Bu. Results Gel retardation assay showed complete condensation of pDNA at weight ratio ＞15. At concentrations ranging from 5 to 100 μg/mL, cytotoxicity of Gal-Bu and PEI 25 000 increased with the concentrations. Gal-Bu exhibited lower cytotoxicity than PEI 25 000 at the same concentration (P＜0.01）. The polymer performed the highest transfection efficiency at weight ratio of 50, which was 5.6 times of PEI 25 000 （P＜0.01） and was close to Lipofectamine 2000. Competition assay of galactose revealed that the transfection efficiency of Gal-Bu was significantly decreased in the presence of 100 mmol/L galactose （P＜0.01）, whereas this phenomenon was not observed on the transfection efficiency of PEI-Bu (P＞0.05). Conclusion Gal-Bu is a non-viral hepatocyte-targeting gene carrier with lower cytotoxicity and enhanced transfection efficiency, which would be a promising candidate in hepatocyte-targeting gene therapy.