Goncin Una, Curiel Laura, Geyer C Ronald, Machtaler Steven
Department of Medical Imaging, University of Saskatchewan, Saskatoon, SK, S7N 5E5, Canada.
Department of Electrical and Software Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB, T2N 4V8, Canada.
Mol Imaging Biol. 2023 Apr;25(2):283-293. doi: 10.1007/s11307-022-01755-9. Epub 2022 Jul 18.
Our objectives were to develop a targeted microbubble with an anti-P-selectin aptamer and assess its ability to detect bowel inflammation in two murine models of acute colitis.
Lipid-shelled microbubbles were prepared using mechanical agitation. A rapid copper-free click chemistry approach (azide-DBCO) was used to conjugate the fluorescent anti-P-selectin aptamer (Fluor-P-Ap) to the microbubble surface. Bowel inflammation was chemically induced using 2,4,6-trinitrobenzenesulfonic acid (TNBS) in both Balb/C and interleukin-10-deficient (IL-10 KO) mice. Mouse bowels were imaged using non-linear contrast mode following an i.v. bolus of 1 × 10 microbubbles. Each mouse received a bolus of aptamer-functionalized and non-targeted microbubbles. Mouse phenotypes and the presence of P-selectin were validated using histology and immunostaining, respectively.
Microbubble labelling of Fluor-P-Ap was complete after 20 min at 37 ̊C. We estimate approximately 300,000 Fluor-P-Ap per microbubble and confirmed fluorescence using confocal microscopy. There was a significant increase in ultrasound molecular imaging signal from both Balb/C (p = 0.003) and IL-10 KO (p = 0.02) mice with inflamed bowels using aptamer-functionalized microbubbles in comparison to non-targeted microbubbles. There was no signal in healthy mice (p = 0.4051) using either microbubble.
We constructed an aptamer-functionalized microbubble specific for P-selectin using a clinically relevant azide-DBCO click reaction, which could detect bowel inflammation in vivo. Aptamers have potential as a next generation targeting agent for developing cost-efficient and clinically translatable targeted microbubbles.
我们的目标是研发一种带有抗P-选择素适体的靶向微泡，并评估其在两种急性结肠炎小鼠模型中检测肠道炎症的能力。
采用机械搅拌制备脂质包裹的微泡。使用快速无铜点击化学方法（叠氮化物-二苯并环辛炔）将荧光抗P-选择素适体（Fluor-P-Ap）偶联到微泡表面。在Balb/C小鼠和白细胞介素-10缺陷（IL-10 KO）小鼠中，使用2,4,6-三硝基苯磺酸（TNBS）化学诱导肠道炎症。静脉注射1×10个微泡后，采用非线性对比模式对小鼠肠道进行成像。每只小鼠接受一次适体功能化微泡和非靶向微泡的推注。分别使用组织学和免疫染色验证小鼠表型和P-选择素的存在。
在37℃下20分钟后，Fluor-P-Ap对微泡的标记完成。我们估计每个微泡上约有300,000个Fluor-P-Ap，并使用共聚焦显微镜确认了荧光。与非靶向微泡相比，使用适体功能化微泡时，Balb/C小鼠（p = 0.003）和IL-10 KO小鼠（p = 0.02）肠道炎症的超声分子成像信号显著增加。使用任何一种微泡时，健康小鼠均无信号（p = 0.4051）。
我们使用临床相关的叠氮化物-二苯并环辛炔点击反应构建了一种对P-选择素具有特异性的适体功能化微泡，其可在体内检测肠道炎症。适体作为下一代靶向剂，在开发具有成本效益且可临床转化的靶向微泡方面具有潜力。
