The ability to successfully pinpoint and subsequently destroy cancer cells using biologically inert material and noninvasive methods is ideal for low-risk procedures. One way to accomplish this is using plasmonic gold nanoparticles, which have two-photon photoluminescence (2PPL) and photothermal properties that can be triggered by deep-tissue-penetrable near-infrared (NIR) light (650–950 nm). Herein, the first 2PPL of hollow gold nanospheres (HGNs) is reported using multiphoton luminescence microscopy. The two-photon action cross-section of the HGNs, using gold nanorods (GNRs) as a reference, is 1.02 × 10⁶ GM at 820 nm. Additionally, the HGNs have ∼0.75 times the 2PPL quantum yield of GNRs. The larger two-photon action cross-section and lower quantum yield correspond to a higher efficiency for heat generation desired for photothermal conversion applications. To this end, the 2PPL and photothermal properties of HGNs can be applied toward simultaneous cancer cell imaging and photothermal therapy (PTT). HGNs bioconjugated with folic acid–PEG–thiol (HGN-FA) selectively bind to the overexpressed folate receptor of cervical cancer HeLa cells and the 2PPL from HGN-FA captures high-resolution cancer cell images. Subsequent power increase and laser scanning dwell time result in highly efficient photothermal destruction of cancer cells. Using femtosecond laser pulses, microseconds of laser exposure generate well-localized superheating of HGNs, yielding subcellular thermal damage and cell death.

中文翻译：

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空心金纳米球的双光子光致发光和光热性质，用于高效的治疗学应用

使用生物惰性材料和非侵入性方法成功查明并随后破坏癌细胞的能力是低风险手术的理想选择。一种实现此目的的方法是使用等离激元金纳米粒子，该粒子具有双光子光致发光（2PPL）和光热特性，这些特性可以由深层组织可穿透的近红外（NIR）光（650-950 nm）触发。本文中，使用多光子发光显微镜报道了中空金纳米球（HGN）的第一个2PPL。以金纳米棒（GNR）为参考，HGN的两光子作用截面为1.02×10 ⁶GM在820 nm。此外，HGN的GNR的2PPL量子产率约为0.75倍。较大的双光子作用截面和较低的量子产率对应于光热转换应用所需的较高的热产生效率。为此，HGNs的2PPL和光热特性可用于同时进行的癌细胞成像和光热疗法（PTT）。与叶酸-PEG-硫醇（HGN-FA）生物缀合的HGNs选择性结合宫颈癌HeLa细胞的过表达叶酸受体，HGN-FA的2PPL捕获高分辨率癌细胞图像。随后的功率增加和激光扫描停留时间导致癌细胞的高效光热破坏。使用飞秒激光脉冲，微秒的激光照射会导致HGN的局部过热，