Li Jing-Liang, Hou Xue-Liang, Bao Hong-Chun, Sun Lu, Tang Bin, Wang Jin-Feng, Wang Xun-Gai, Gu Min
Institute for Frontier Materials, Deakin University, Waurn Ponds, Victoria, 3216, Australia.
J Biomed Mater Res A. 2014 Jul;102(7):2181-8. doi: 10.1002/jbm.a.34871. Epub 2013 Aug 10.
Nano-sized graphene and graphene oxide (GO) are promising for biomedical applications, such as drug delivery and photothermal therapy of cancer. It is observed in this work that the ultrafast reduction of GO nanoparticles (GONs) with a femtosecond laser beam creates extensive microbubbling. To understand the surface chemistry of GONs on the microbubble formation, the GONs were reduced to remove most of the oxygen-containing groups to get reduced GONs (rGONs). Microbubbling was not observed when the rGONs were irradiated by the laser. The instant collapse of the microbubbles may produce microcavitation effect that brings about localized mechanical damage. To understand the potential applications of this phenomenon, cancer cells labeled with GONs or rGONs were irradiated with the laser. Interestingly, the microbubbling effect greatly facilitated the destruction of cancer cells. When microbubbles were produced, the effective laser power was reduced to less than half of what is needed when microbubbling is absent. This finding will contribute to the safe application of femtosecond laser in the medical area by taking advantage of the ultrafast reduction of GONs. It may also find other important applications that need highly localized microcavitation effects.
纳米尺寸的石墨烯和氧化石墨烯（GO）在生物医学应用方面具有广阔前景，例如癌症的药物递送和光热治疗。在这项工作中观察到，用飞秒激光束对氧化石墨烯纳米颗粒（GONs）进行超快还原会产生大量微气泡。为了了解GONs在微气泡形成过程中的表面化学性质，对GONs进行还原以去除大部分含氧基团，从而得到还原型氧化石墨烯纳米颗粒（rGONs）。当用激光照射rGONs时未观察到微气泡现象。微气泡的瞬间崩塌可能会产生微空化效应，进而造成局部机械损伤。为了了解这一现象的潜在应用，用激光照射标记有GONs或rGONs的癌细胞。有趣的是，微气泡效应极大地促进了癌细胞的破坏。当产生微气泡时，有效激光功率降低到无微气泡时所需功率的一半以下。这一发现将有助于通过利用GONs的超快还原特性，在医学领域安全应用飞秒激光。它还可能在其他需要高度局部微空化效应的重要应用中发挥作用。
