Weems A C, Raymond J E, Easley A D, Wierzbicki M A, Gustafson T, Monroe Mbb, Maitland D J
Biomedical Device Laboratory, Dept of Biomedical Engineering, Texas A&M University, College Station, TX, 77860.
Laboratory for Synthetic-Biologic Interface, Dept of Chemistry, Texas A&M University, College Station, TX, 77860.
RSC Adv. 2017;7(32):19742-19753. doi: 10.1039/C6RA28165F. Epub 2017 Apr 4.
Shape memory polymers (SMPs) are promising for non-invasive medical devices and tissue scaffolds, but are limited by a lack of visibility under clinical imaging. Fluorescent dyes are an alternative to radiocontrast agents in medical applications, they can be utilized in chemical sensors and monitors and may be anti-microbial agents. Thus, a fluorescent SMP could be a highly valuable biomaterial system. Here, we show that four fluorescent dyes (phloxine B (PhB), eosin Y (Eos), indocyanine green(IcG), and calcein (Cal)) can be crosslinked into the polymer backbone to enhance material optical properties without alteration of shape memory and thermomechanical properties. Examinations of the emission wavelengths of the materials compared with the dye solutions showed a slight red shift in the peak emissions, indicative of crosslinking of the material. Quantitative analysis revealed that PhB enabled visibility through 1 cm of blood and through soft tissue. We also demonstrate the utility of these methods in combination with radio-opaque microparticle additives and the use of laser-induced shape recovery to allow for rapid shape recovery below the glass transition temperature. The crosslinking of fluorescent dyes into the SMP enables tuning of physical properties and shape memory and independently of the fluorescence functionality. This fluorescent SMP biomaterial system allows for use of multiple imaging modalities with potential application in minimally invasive medical devices.
形状记忆聚合物（SMPs）在无创医疗设备和组织支架方面颇具前景，但受限于临床成像时缺乏可见性。在医学应用中，荧光染料可替代放射性造影剂，可用于化学传感器和监测器，还可能是抗菌剂。因此，荧光SMP可能是一种极具价值的生物材料系统。在此，我们表明四种荧光染料（玫瑰红B（PhB）、伊红Y（Eos）、吲哚菁绿（IcG）和钙黄绿素（Cal））可交联到聚合物主链中，以增强材料的光学性能，同时不改变形状记忆和热机械性能。将材料的发射波长与染料溶液进行比较后发现，峰值发射有轻微红移，这表明材料发生了交联。定量分析表明，PhB能使材料透过1厘米厚的血液和软组织可见。我们还展示了这些方法与不透射线的微粒添加剂相结合的效用，以及利用激光诱导形状恢复来实现低于玻璃化转变温度时的快速形状恢复。荧光染料交联到SMP中可调节物理性能和形状记忆，且与荧光功能无关。这种荧光SMP生物材料系统允许使用多种成像方式，在微创医疗设备中具有潜在应用价值。
