Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu, Taiwan 30013.
Langmuir. 2011 Jun 7;27(11):6971-6. doi: 10.1021/la2011259. Epub 2011 May 9.
Targeted ultrasound contrast agents can be prepared by some specific bioconjugation techniques. The biotin-avidin complex is an extremely useful noncovalent binding system, but the system might induce immunogenic side effects in human bodies. Previous proposed covalently conjugated systems suffered from low conjugation efficiency and complex procedures. In this study, we propose a covalently conjugated nanobubble coupling with nucleic acid ligands, aptamers, for providing a higher specific affinity for ultrasound targeting studies. The sgc8c aptamer was linked with nanobubbles through thiol-maleimide coupling chemistry for specific targeting to CCRF-CEM cells. Further improvements to reduce the required time and avoid the degradation of nanobubbles during conjugation procedures were also made. Several investigations were used to discuss the performance and consistency of the prepared nanobubbles, such as size distribution, conjugation efficiency analysis, and flow cytometry assay. Further, we applied our conjugated nanobubbles to ex vivo ultrasound targeted imaging and compared the resulting images with optical images. The results indicated the availability of aptamer-conjugated nanobubbles in targeted ultrasound imaging and the practicability of using a highly sensitive ultrasound system in noninvasive biological research.
靶向超声对比剂可以通过一些特定的生物偶联技术来制备。生物素-亲和素复合物是一种非常有用的非共价结合系统，但该系统可能会在人体中引起免疫原性副作用。以前提出的共价偶联系统存在偶联效率低和操作复杂的问题。在本研究中，我们提出了一种通过巯基-马来酰亚胺偶联化学将核酸配体（适配体）与纳米气泡偶联，以提供更高的超声靶向研究特异性亲和力。sgc8c 适配体通过巯基-马来酰亚胺偶联化学与纳米气泡连接，用于特异性靶向 CCRF-CEM 细胞。进一步的改进旨在减少所需时间，并避免在偶联过程中纳米气泡的降解。我们使用了几种方法来讨论制备的纳米气泡的性能和一致性，如粒径分布、偶联效率分析和流式细胞术检测。此外，我们将共轭纳米气泡应用于离体超声靶向成像，并将得到的图像与光学图像进行比较。结果表明，适配体偶联纳米气泡在靶向超声成像中的可用性，以及在非侵入性生物研究中使用高灵敏度超声系统的可行性。
