The presence of positive surgical margins confers an increased risk of biochemical relapse and need for salvage therapy in men undergoing radical prostatectomy. Image-guided surgery using near-infrared (NIR) fluorescent contrast agents is a potential method to detect remaining cancerous tissue. The objective of this study was to evaluate three hyaluronic acid (HA) nanoparticle (NP) formulations loaded with NIR fluorophore for their ability to contrast-enhance prostate cancer. HA was modified by conjugation with the hydrophobic ligand, aminopropyl-1-pyrenebutanamide to drive nanoparticle self-assembly. Indocyanine green (ICG) was physicochemically entrapped in the HA-NP, termed NanoICG. Alternatively, Cy7.5 was directly conjugated to amphiphilic HA, termed NanoCy7.5. NanoCy7.5 was synthesized with two HA molecular weights to determine the HA size contribution to delivery to PC3 prostate tumor xenografts. Contrast-enhancement of the tumors and relative biodistribution were assessed by a series of fluorescence imaging, image-guided surgery with spectroscopy, and microscopic techniques. Intravenously administered NanoICG improved tumor signal-to-noise ratio (SNR) at 24 h over ICG by 2.9-fold. NanoCy7.5 with 10 kDa and 100kDa HA improved tumor SNR by 6.6- and 3.1-fold over Cy7.5 alone, respectively. The PC3 xenograft was clearly identified with the image-guided system providing increased contrast enhancement compared to surrounding tissue for NanoICG and NanoCy7.5 with 10 kDa HA. NIR fluorescence microscopy showed that Cy7.5 in NPs with 10 kDa HA were distributed throughout the tumor, while NanoCy7.5 with 100 kDa HA or NanoICG delivered dye mainly to the edge of the tumor. CD31 staining suggested that PC3 tumors are poorly vascularized. These studies demonstrate the efficacy of a panel of HA-derived NPs in identifying prostate tumors in vivo, and suggest that by tuning the structural properties of these NPs, optimized delivery can be achieved to poorly vascularized tumors.

Statement of Significance

We have demonstrated the potential of a panel of near-infrared fluorescent (NIRF) nanoparticles (NPs) for image-guided surgery in a prostate cancer xenograft model. Image-guided surgery and imaging of organs ex vivo showed greater tumor signal and contrast when mice were administered NIRF dyes that were covalently conjugated to (NanoCy7.510k-PBA) or physicochemically entrapped in (NanoICGPBA) hyaluronic acid (HA) NPs, compared to free dyes. These results show the potential to use these NPs as tools to detect the margins of tumors and to differentiate healthy and tumor tissue intraoperatively. Moreover, this project provides insight into selecting optimal formulation strategies for poorly vascularized tumors.

中文翻译：

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透明质酸配方的近红外荧光团可优化前列腺肿瘤异种移植的手术成像

手术切缘阳性的存在增加了接受前列腺癌根治术的男性生化复发的风险，并需要进行挽救治疗。使用近红外（NIR）荧光造影剂的图像引导手术是检测残留癌变组织的潜在方法。这项研究的目的是评估三种装有NIR荧光团的透明质酸（HA）纳米颗粒（NP）制剂增强对比剂的能力。HA通过与疏水性配体氨丙基-1-吡丁烯酰胺共轭修饰，以驱动纳米粒子的自组装。吲哚菁绿（ICG）被物理化学包裹在称为NanoICG的HA-NP中。或者，将Cy7.5直接偶联至两亲性HA，称为NanoCy7.5。NanoCy7。合成具有两个HA分子量的5，以确定HA尺寸对递送至PC3前列腺肿瘤异种移植物的贡献。通过一系列荧光成像，带光谱的图像引导手术和显微镜技术评估肿瘤的对比度增强和相对生物分布。与ICG相比，静脉注射NanoICG在24 h时可将肿瘤信噪比（SNR）提高2.9倍。与单独的Cy7.5相比，具有10 kDa和100kDa HA的NanoCy7.5分别将肿瘤信噪比提高了6.6倍和3.1倍。与具有10 kDa HA的NanoICG和NanoCy7.5的周围组织相比，图像引导系统可以清楚地识别PC3异种移植物，从而提供增强的对比度增强。NIR荧光显微镜检查显示，具有10 kDa HA的NP中的Cy7.5分布在整个肿瘤中，而NanoCy7。5具有100 kDa HA或NanoICG的染料主要递送至肿瘤边缘。CD31染色提示PC3肿瘤血管形成不良。这些研究证明了一组HA衍生的NP在鉴定前列腺肿瘤中的功效在体内，并建议通过调节这些NP的结构特性，可以实现最佳递送至血管化不良的肿瘤。

重要声明

我们已经证明了一组近红外荧光（NIRF）纳米粒子（NPs）在前列腺癌异种移植模型中进行图像引导手术的潜力。与给小鼠共价结合（NanoCy7.510k-PBA）或物理化学包裹在（NanoICGPBA）透明质酸（HA）NP中的NIRF染料相比，图像引导的手术和离体器官成像显示出更大的肿瘤信号和对比度。游离染料。这些结果表明使用这些NP作为工具来检测肿瘤边缘并在术中区分健康组织和肿瘤组织的潜力。此外，该项目为选择血管形成不良的肿瘤的最佳制剂策略提供了见识。