Nanosize structures activated by near-infrared (NIR) photoexcitation can provide an optical platform for the image-guided removal of small tumor nodules. We have engineered nanoparticles derived from erythrocytes that can be doped with NIR fluorophore indocyanine green (ICG). We refer to these constructs as NIR erythrocyte-derived transducers (NETs). The objective of this study was to determine if ICG-bound albumin (IbA), as the doping material, could enhance the fluorescence emission of NETs, and evaluate the capability of these nanoprobes in imaging cancer cells. Erythrocytes were isolated from bovine whole blood and depleted of hemoglobin to form erythrocyte ghosts (EGs). EGs were then extruded through nanosize porous membranes in the presence of 10–100 μm ICG or Iba (1:1 molar ratio) to form ICG- or IbA-doped NETs. The resulting nanosize constructs were characterized for their diameters, zeta-potentials, absorption, and fluorescence emission spectra. We used fluorescence microscopic imaging to evaluate the capability of the constructs in imaging SKOV3 ovarian cancer cells. Based on dynamic light-scattering measurements, ICG- and IbA-doped NETs had similar diameter distributions (Z-average diameter of 236 and 238 nm, respectively) in phosphate-buffered saline supplemented with 10% fetal bovine serum, which remained nearly constant over the course of 2 h at 37 °C. Despite a much-lower loading efficiency of IbA (∼0.7–8%) as compared to ICG (10–45%), the integrated normalized fluorescence emission of IbA-NETs was 2- to 6-fold higher than ICG-doped NETs. IbA-NETs also demonstrated an enhanced capability in fluorescence imaging of SKOV3 ovarian cancer cells, and can serve as potentially effective nanoprobes for the fluorescence imaging of cancerous cells.

中文翻译：

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吲哚菁绿结合白蛋白掺杂的红细胞衍生光学纳米探针：癌细胞成像的材料特性和评价

通过近红外（NIR）光激发激活的纳米尺寸结构可以为图像引导的小肿瘤结节切除提供光学平台。我们已经设计了可以掺入NIR荧光团吲哚菁绿（ICG）的红细胞纳米颗粒。我们将这些构建体称为NIR红细胞衍生的换能器（NETs）。这项研究的目的是确定ICG结合白蛋白（IbA）作为掺杂材料是否可以增强NETs的荧光发射，并评估这些纳米探针在成像癌细胞中的能力。从牛全血中分离出红血球，并去除血红蛋白，形成红血球重影（EGs）。然后，在10–100μmICG或Iba（1：1摩尔比）的存在下，将EG通过纳米级多孔膜挤出，以形成掺杂ICG或IbA的NET。表征所得纳米级构建体的直径，ζ电势，吸收和荧光发射光谱。我们使用荧光显微镜成像来评估构建体在成像SKOV3卵巢癌细胞中的能力。根据动态光散射测量，掺杂ICG和IbA的NET的直径分布相似（在补充有10％胎牛血清的磷酸盐缓冲盐水中，Z轴平均直径分别为236和238 nm，在37°C下2 h的过程中几乎保持恒定。尽管与ICG（10-45％）相比，IbA的负载效率要低得多（〜0.7–8％），但IbA-NET的集成归一化荧光发射要比掺杂ICG的NET高2至6倍。IbA-NETs还显示出SKOV3卵巢癌细胞的荧光成像功能增强，并且可以用作癌细胞荧光成像的潜在有效纳米探针。