Yu Shuai, Cheng Bingbing, Yao Tingfeng, Xu Cancan, Nguyen Kytai T, Hong Yi, Yuan Baohong
Ultrasound and Optical Imaging Laboratory, Department of Bioengineering, The University of Texas at Arlington, Arlington, TX 76019, USA.
Joint Biomedical Engineering Program, The University of Texas at Arlington and The University of Texas Southwestern Medical Center at Dallas, TX 75390, USA.
Sci Rep. 2016 Oct 24;6:35942. doi: 10.1038/srep35942.
Recently, we developed a new technology, ultrasound-switchable fluorescence (USF), for high-resolution imaging in centimeter-deep tissues via fluorescence contrast. The success of USF imaging highly relies on excellent contrast agents. ICG-encapsulated poly(N-isopropylacrylamide) nanoparticles (ICG-NPs) are one of the families of the most successful near-infrared (NIR) USF contrast agents. However, the first-generation ICG-NPs have a short shelf life (<1 month). This work significantly increases the shelf life of the new-generation ICG-NPs (>6 months). In addition, we have conjugated hydroxyl or carboxyl function groups on the ICG-NPs for future molecular targeting. Finally, we have demonstrated the effect of temperature-switching threshold (T) and the background temperature (T) on the quality of USF images. We estimated that the T of the ICG-NPs should be controlled at ~38-40 °C (slightly above the body temperature of 37 °C) for future in vivo USF imaging. Addressing these challenges further reduces the application barriers of USF imaging.
最近，我们开发了一种新技术，即超声可切换荧光（USF），用于通过荧光造影在厘米深的组织中进行高分辨率成像。USF成像的成功高度依赖于优异的造影剂。包裹吲哚菁绿（ICG）的聚（N-异丙基丙烯酰胺）纳米颗粒（ICG-NPs）是最成功的近红外（NIR）USF造影剂家族之一。然而，第一代ICG-NPs的保质期较短（<1个月）。这项工作显著延长了新一代ICG-NPs的保质期（>6个月）。此外，我们在ICG-NPs上连接了羟基或羧基官能团，以备将来进行分子靶向。最后，我们展示了温度切换阈值（T）和背景温度（T）对USF图像质量的影响。我们估计，为了未来的体内USF成像，ICG-NPs的T应控制在~38-40°C（略高于37°C的体温）。应对这些挑战进一步降低了USF成像的应用障碍。
