Biomedical Engineering, The University of Texas At Austin, Austin, TX, 78712, USA.
Mechanical Engineering, The University of Texas At Austin, Austin, TX, 78712, USA.
Sci Rep. 2020 Jul 24;10(1):12387. doi: 10.1038/s41598-020-68512-2.
Plasmonic Laser Nanosurgery (PLN) is a novel photomodification technique that exploits the near-field enhancement of femtosecond (fs) laser pulses in the vicinity of gold nanoparticles. While prior studies have shown the advantages of fs-PLN to modify cells, further reduction in the pulse fluence needed to initiate photomodification is crucial to facilitate deep-tissue treatments. This work presents an in-depth study of fs-PLN at ultra-low pulse fluences using 47 nm gold nanoparticles, conjugated to antibodies that target the epithelial growth factor receptor and excited off-resonance using 760 nm, 270 fs laser pulses at 80 MHz repetition rate. We find that fs-PLN can optoporate cellular membranes with pulse fluences as low as 1.3 mJ/cm, up to two orders of magnitude lower than those used at lower repetition rates. Our results, corroborated by simulations of free-electron generation by particle photoemission and photoionization of the surrounding water, shed light on the off-resonance fs-PLN mechanism. We suggest that photo-chemical pathways likely drive cellular optoporation and cell damage at these off-resonance, low fluence, and high repetition rate fs-laser pulses, with clusters acting as local concentrators of ROS generation. We believe that the low fluence and highly localized ROS-mediated fs-PLN approach will enable targeted therapeutics and cancer treatment.
等离子体激光纳米手术（PLN）是一种新颖的光修饰技术，利用飞秒（fs）激光脉冲在金纳米粒子附近的近场增强。虽然先前的研究已经表明 fs-PLN 在修饰细胞方面具有优势，但进一步降低引发光修饰所需的脉冲强度对于促进深层组织治疗至关重要。本工作深入研究了使用 47nm 金纳米粒子的超低声学脉冲 fs-PLN，这些纳米粒子与针对表皮生长因子受体的抗体结合，并使用 760nm、270fs 的激光脉冲在 80MHz 的重复率下离频激发。我们发现 fs-PLN 可以用低至 1.3mJ/cm 的脉冲强度来光穿孔细胞膜，比在较低重复率下使用的强度低两个数量级。我们的结果得到了粒子光致发射和周围水的光致离化产生自由电子的模拟的证实，阐明了离频 fs-PLN 机制。我们认为，在这些离频、低强度和高重复率的 fs 激光脉冲下，光化学途径可能驱动细胞光穿孔和细胞损伤，而簇则充当 ROS 生成的局部集中器。我们相信，低强度和高度局域的 ROS 介导的 fs-PLN 方法将能够实现靶向治疗和癌症治疗。
