Fomina Nadezda, McFearin Cathryn L, Sermsakdi Marleen, Morachis José M, Almutairi Adah
Skaggs School Pharmacy and Pharmaceutical Sciences, Department of NanoEngineering, Materials Science and Engineering and Biomedical Sciences Programs, University of California at San Diego, La Jolla, California 92093.
Macromolecules. 2011;44(21):8590-8597. doi: 10.1021/ma201850q.
Near infrared (NIR) irradiation can penetrate up to 10 cm deep into tissues and be remotely applied with high spatial and temporal precision. Despite its potential for various medical and biological applications, there is a dearth of biomaterials that are responsive at this wavelength region. Herein we report a polymeric material that is able to disassemble in response to biologically benign levels of NIR irradiation upon two-photon absorption. The design relies on the photolysis of the multiple pendant 4-bromo7-hydroxycoumarin protecting groups to trigger a cascade of cyclization and rearrangement reactions leading to the degradation of the polymer backbone. The new material undergoes a 50% Mw loss after 25 sec of ultraviolet (UV) irradiation by single photon absorption and 21 min of NIR irradiation via two-photon absorption. Most importantly, even NIR irradiation at biologically benign laser power is sufficient to cause significant polymer disassembly. Furthermore, this material is well tolerated by cells both before and after degradation. These results demonstrate for the first time a NIR sensitive material with potential to be used for in vivo applications.
近红外（NIR）辐射能够穿透组织达10厘米深，并能以高空间和时间精度进行远程应用。尽管其在各种医学和生物学应用中具有潜力，但在该波长区域响应的生物材料却很匮乏。在此，我们报道了一种聚合物材料，该材料在双光子吸收后能够响应生物良性水平的近红外辐射而分解。该设计依赖于多个侧链4-溴-7-羟基香豆素保护基团的光解，以引发一系列环化和重排反应，导致聚合物主链降解。通过单光子吸收进行25秒紫外线（UV）照射以及通过双光子吸收进行21分钟近红外照射后，新材料的分子量损失了50%。最重要的是，即使在生物良性激光功率下进行近红外照射也足以导致聚合物显著分解。此外，这种材料在降解前后细胞都具有良好的耐受性。这些结果首次证明了一种具有体内应用潜力的近红外敏感材料。
