Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States.
Xidian University, Engineering Research Center of Molecular and Neuro Imaging, School of Life Scienc, China.
J Biomed Opt. 2019 Mar;24(3):1-5. doi: 10.1117/1.JBO.24.3.035004.
The observed behavior of short-wave infrared (SWIR) light in tissue, characterized by relatively low scatter and subdiffuse photon transport, has generated considerable interest for the potential of SWIR imaging to produce high-resolution, subsurface images of fluorescence activity in vivo. These properties have important implications for fluorescence-guided surgery and preclinical biomedical research. Until recently, translational efforts have been impeded by the conventional understanding that fluorescence molecular imaging in the SWIR regime requires custom molecular probes that do not yet have proven safety profiles in humans. However, recent studies have shown that two readily available near-infrared (NIR-I) fluorophores produce measurable SWIR fluorescence, implying that other conventional fluorophores produce detectable fluorescence in the SWIR window. Using SWIR spectroscopy and wide-field SWIR imaging with tissue-simulating phantoms, we characterize and compare the SWIR emission properties of eight commercially available red/NIR-I fluorophores commonly used in preclinical and clinical research, in addition to a SWIR-specific fluorophore. All fluorophores produce measurable fluorescence emission in the SWIR, including shorter wavelength dyes such as Alexa Fluor 633 and methylene blue. This study is the first to report SWIR fluorescence from six of the eight conventional fluorophores and establishes an important comparative reference for developing and evaluating SWIR imaging strategies for biomedical applications.
组织中短波长近红外（SWIR）光的观察到的行为，其特点是相对较低的散射和亚扩散光子输运，这激发了人们对 SWIR 成像在体内产生高分辨率、亚表面荧光活性图像的潜力的极大兴趣。这些特性对荧光引导手术和临床前生物医学研究具有重要意义。直到最近，由于传统的理解，即 SWIR 区域中的荧光分子成像是需要定制的分子探针，而这些探针在人类中还没有经过验证的安全性，因此转化工作受到了阻碍。然而，最近的研究表明，两种现成的近红外（NIR-I）荧光团会产生可测量的 SWIR 荧光，这意味着其他常规荧光团会在 SWIR 窗口中产生可检测的荧光。我们使用 SWIR 光谱和具有组织模拟体的广角 SWIR 成像，对在临床前和临床研究中常用的八种市售的红色/NIR-I 荧光团的 SWIR 发射特性进行了表征和比较，此外还包括一种 SWIR 特异性荧光团。所有荧光团在 SWIR 中都会产生可测量的荧光发射，包括较短波长的染料，如 Alexa Fluor 633 和亚甲蓝。这项研究首次报道了其中八种常规荧光团中的六种的 SWIR 荧光，并为开发和评估用于生物医学应用的 SWIR 成像策略建立了一个重要的比较参考。
