摘要目的:探讨自制的诊疗一体化相变纳米液滴"IR780/叶酸－纳米液滴－多西紫杉醇(IR780/FA-Nds-DTX)"作为分子靶向超声造影剂，对胰腺癌荷瘤裸鼠的精准诊断和联合靶向治疗效果。方法:体外培养胰腺癌细胞系，建立异位皮下移植胰腺癌荷瘤裸鼠模型50只，双模态靶向成像分实验组(IR780/FA-Nds-DTX)和4个对照组[生理盐水、Nds(FITC)、FA-Nds(FITC)、IR-780]。小动物活体成像验证IR780/FA-Nds-DTX对肿瘤的体内高效靶向探测能力及近红外荧光成像，低强度聚焦超声诱导相变及进一步超声造影成像验证IR780/FA-Nds-DTX在肿瘤局部的高效聚集及对肿瘤轮廓的精准评估。治疗效果观察分实验组(IR780/FA-Nds-DTX)和4个对照组(FA-Nds-IR780、FA-Nds-DTX、FA-Nds和生理盐水)。低强度聚焦超声辐照30 s诱导各组相变后的微泡爆破后，808 nm光热治疗仪分组辐照肿瘤局部，治疗前及治疗后3 d、9 d、15 d分别用二维超声监测各组荷瘤裸鼠肿瘤体积变化并记录，对比各组肿瘤体积变化率及抑制率。结果:IR780/FA-Nds-DTX在肿瘤局部靶向聚集的量最多，实验组肿瘤平均荧光强度明显高于对照组：IR780/FA-Nds-DTX组比Nds(FITC)组[(5.12±0.69)×10 7比(1.06±0.23)×10 7， P<0.05]，IR780/FA-Nds-DTX组比FA-Nds(FITC)组[(5.12±0.69)×10 7比(2.98±0.34)×10 7， P<0.05]，IR780/FA-Nds-DTX组比IR-780组[(5.12±0.69)×10 7比(1.54±0.42)×10 7， P<0.05]，生理盐水组肿瘤局部无荧光显示。进一步液滴相变后形成的超声增强显影能更精准定位肿瘤边界。光热消融联合化疗后第15 d，IR780/FA-Nds-DTX治疗组肿瘤体积增长率较各对照组明显减低：IR780/FA-Nds-DTX组比FA-Nds-IR780组[(0.105±0.075)比(0.405±0.175)， P<0.05]，IR780/FA-Nds-DTX组比FA-Nds-DTX组[(0.105±0.075)比(1.385±0.035)， P<0.05]，IR780/FA-Nds-DTX组比FA-Nds组[(0.105±0.075)比(2.255±0.105)， P<0.05]，IR780/FA-Nds-DTX组比生理盐水组[(0.105±0.075)比(2.185±0.155)， P<0.05]。而肿瘤体积抑制率明显增高：IR780/FA-Nds-DTX组比FA-Nds-IR780组[(0.93±0.06)比(0.48±0.17)， P<0.05]，IR780/FA-Nds-DTX组比FA-Nds-DTX组[(0.93±0.06)比(－0.51±0.105)， P<0.05]，IR780/FA-Nds-DTX组比FA-Nds组[(0.93±0.06)比(－1.63±0.115)， P<0.05]，IR780/FA-Nds-DTX组比生理盐水组[(0.93±0.06)比(－1.35±0.245)， P<0.05]。 结论:自制的诊疗一体化双模态相变纳米液滴超声造影剂IR780/FA-Nds-DTX在胰腺癌微小病灶甚至转移灶的精准靶向探测与联合靶向治疗中具有较好的潜在临床应用价值。

abstractsObjective:To investigate the effect of self-made phase-change nanodroplets IR780/FA-Nds-DTX as molecular targeted ultrasound contrast agents for accurate diagnosis and combined targeted therapy of pancreatic cancer.Methods:Pancreatic cancer cell lines were cultured in vitro and 50 tumor bearing nude mouse models were established. The experimental group (IR780/ FA-NdS-DTX) and four control groups[ normal saline, Nds(FITC), FA-Nds (FITC) and IR-780] were divided to verify dual-mode targeted imaging. The imaging using the IVIS Imaging System verified the high-efficiency targeted detection ability and near-infrared fluorescence imaging of IR780/FA-Nds-DTX for tumors in vivo, phase transformation induced by low-intensity focused ultrasound and further contrast-enhanced ultrasound imaging verified the high-efficiency aggregation of IR780/FA-Nds-DTX in local tumors and accurate evaluation of tumor contour. The therapeutic effect was observed in the experimental group (IR780/FA-Nds-DTX) and four control groups (FA-Nds-IR780, FA-Nds-DTX, FA-Nds and normal saline). After low-intensity focused ultrasound irradiation for 30s induced microbubble blasting after phase transformation in each group, 808nm photothermal therapy apparatus was used to irradiate tumor area in each group. Two-dimensional ultrasound was used to monitor the changes in tumor volume in each group before and at 3 d, 9 d, 15 d after treatment, and the changes in tumor volume rate and inhibition in each group were statistically analyzed and compared.Results:The amount of IR780/ FA-Nds-DTX locally targeted aggregation was the largest, and the average fluorescence intensity of tumor in the experimental group was significantly higher than that of the control groups: IR780/ FA-Nds-DTX group compared with Nds(FITC) group[(5.12±0.69)×10 7 vs (1.06±0.23)×10 7, P<0.05], IR780/FA-Nds-DTX group compared with FA-Nds (FITC) group [(5.12±0.69)×10 7 vs (2.98±0.34)×10 7, P<0.05], IR780/FA-Nds-DTX group compared with IR-780 group [(5.12±0.69)×10 7 vs (1.54±0.42)×10 7, P<0.05], and there was no fluorescence in tumor area in saline group. Further contrast-enhanced ultrasound imaging after nanodroplet phase transformation could more accurately locate the tumor boundary. After 15 days of photothermal ablation combined with chemotherapy, the growth rate of tumor volume in the IR780/ FA-Nds-DTX treatment group was significantly lower than that in the control groups: IR780/FA-Nds-DTX group compared with FA-Nds-IR780 group[(0.105±0.075) vs (0.405±0.175), P<0.05], IR780/ FA-Nds-DTX group compared with FA-Nds-DTX group [(0.105±0.075) vs (1.385±0.035), P<0.05], IR780/ FA-Nds-DTX group compared with FA-Nds group [(0.105±0.075) vs (2.255±0.105), P<0.05], IR780/ FA-Nds-DTX group compared with normal saline group [(0.105±0.075) vs (2.185±0.155), P<0.05]. And the tumor inhibition rate increased significantly: IR780/ FA-Nds-DTX group compared with FA-Nds-IR780 group [(0.93±0.06) vs (0.48±0.17), P<0.05], IR780/ FA-Nds-DTX group compared with FA-Nds-DTX group [(0.93±0.06) vs (-0.51±0.105), P<0.05], IR780/ FA-Nds-DTX group compared with FA-Nds group [(0.93±0.06) vs (-1.63±0.115), P<0.05], IR780/ FA-Nds-DTX group compared with normal saline[(0.93±0.06) vs (-1.35±0.245), P<0.05]. Conclusions:The self-made phase-change ultrasound contrast agents IR780/FA-Nds-DTX have good potential clinical value in targeted detection and combined therapy of pancreatic cancer with small lesions or even metastases.