以双歧杆菌为载体实现量子点在体靶向肿瘤的可行性研究

应用双歧双歧杆菌作为量子点输送载体，为小动物在体生物肿瘤成像提供依据. 采用电穿孔方法，将
二棕榈酰磷脂酰胆碱（DPPC）包被的硫硒镉水溶性量子点转入细菌内，得到“量子点-细菌”复合探针，在
“量子点-细菌”表面通过1-(3-二甲氨基丙基)-3-乙基碳二亚胺 (EDC)活化法进一步偶联叶酸分子，制得
“量子点-细菌-叶酸”复合纳米生物探针. 将纳米生物探针经尾静脉注入Lewis肺癌小鼠体内，采用冰冻组
织切片,考察探针在小鼠体内脏器及肿瘤的分布情况. 结果表明，在肿瘤部位检测到较强的量子点光致发光
信号，而在肺、肝、脾等脏器中只检测到微弱的量子点发光信号. “量子点-细菌-叶酸”复合纳米生物探
针小动物在体肿瘤靶向成像是可行的.

Feasibility of in Vivo Imaging using Bifidobacterium bifidum as a Carrier for Delivering Quantum Dots into Tumors

To evaluate the feasibility of in vivo tumor-specific imaging in small animals,Bifidobacterium bifidum was loaded with quantum dots(QDs) and used as a carrier for detecting tumor transplants.First,CdSeS QDs coated with water soluble dipalmitoyl phosphatidylcholine(DPPC) were introduced into B.Bifidum via electroporation.Then,folic acid was used as the second target substance to enhance the affinity of B.Bifidum to tumors through(1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide,EDC) activation method.Last,the obtained QD-B.Bifidum-FA nanobioprobes were intravenously injected into tumor-bearing mice.The frozen tissue sections were used for evaluating the distribution the nanobioprobes in vivo.Stronger characteristic QDs photoluminescence signals were observed in tumors than in other tissues,such as lung,liver and spleen.These results indicated that QD-B.Bifidum-FA nanobioprobes could be used for labeling tumors in small animals in vivo.