Radical Polymer Grafting on the Surface of Single-Walled Carbon Nanotubes Enhances Photoluminescence in the Near-Infrared Region: Implications for Bioimaging and Biosensing
Radical Polymer Grafting on the Surface of Single-Walled Carbon Nanotubes Enhances Photoluminescence in the Near-Infrared Region: Implications for Bioimaging and Biosensing
复制标题
单壁碳纳米管表面的自由基聚合物接枝增强了近红外区域的光致发光：对生物成像和生物传感的影响
DOI：
10.1021/acsanm.0c01561
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发表时间：
2020
影响因子：
5.9
通讯作者：
Fujigaya Tsuyohiko
中科院分区：
文献类型：
--
作者：
Nagai Yukiko;Nakamura Kenta;Yudasaka Masako;Shiraki Tomohiro;Fujigaya Tsuyohiko
单壁碳纳米管(SWCNTs)在近红外区(E11发射)的光致发光(PL)在生物成像和生物传感方面具有很大的吸引力，因为在近红外区人体具有良好的透明性。在这项研究中，我们获得了比自由基聚合物接枝在SWCNT表面的E11更明亮的近红外发射，在这种自由基聚合中，使用表面活性剂分散的SWCNTs进行自由基聚合，即所谓的碳纳米管(CNT)胶束聚合，通过局部官能化(Lf)产生发射sp3缺陷。通过单壁碳纳米管的lf，可分配给E11*和E112*发射的新的PL产生在比E11发射(<；1100 nm)更长的波长(>；1100 nm)，这对于生物成像来说是最好的，以避免来自身体的强烈的自发荧光。结果表明，引发剂浓度和聚合时间对E11*和E112*的发光强度影响很大，随着聚合反应的进行，E11*和E112*的发光变亮，而E11的发光变暗。有趣的是，这种行为还取决于单体的疏水性。疏水单体表现出较快的E11*和E112*发射增加。在最佳条件下，E11*发射强度约为初始E11发射强度的6倍。由于在碳纳米管胶束聚合中还加入了交联剂，聚合物在聚合过程中发生了交联，形成了非常稳定的包覆层。因此，在保持明亮的发光的同时，实现了去除表面活性剂后的稳定分散。
Photoluminescence (PL) of single-walled carbon nanotubes (SWCNTs) in the near-infrared (NIR) region (E11emission) is attractive, especially for bioimaging and biosensingin vivobecause of the good transparency of the body in the NIR region. In this study, we achieved brighter NIR emission of SWCNTs compared withE11emission by radical polymer grafting on the SWCNT surface, in which radical polymerization using surfactant-dispersed SWCNTs, so-called carbon nanotube (CNT) micelle polymerization, generates emissive sp3defects through local functionalization (lf). By lf of SWCNTs, new PL assignable toE11* andE112* emission is generated at a longer wavelength (>1100 nm) thanE11emission (<1100 nm), which is preferable for bioimaging to avoid the strong autofluorescence from the body. It was found that the initiator concentration and polymerization time strongly affect theE11* andE112* emission intensities, and as polymerization progresses,E11* andE112* emission become brighter, whileE11emission becomes darker. Interestingly, such behavior also depends on the hydrophobicity of the monomer. A hydrophobic monomer exhibits more rapid increase ofE11* andE112* emission. At the optimum condition, theE11* emission intensity is about 6 times brighter than the initialE11emission. Because a cross-linker is also added in CNT micelle polymerization, polymer cross-linking occurs during polymerization and a very stable coating layer is formed. Therefore, a stable dispersion after the removal of the surfactant is realized while maintaining bright PL emission.