Lymph nodes (LNs) are immune organs housing high concentrations of lymphocytes, making them critical targets for therapeutic immunomodulation in a wide variety of diseases. While there is great interest in targeted drug delivery to LNs, many nanoscale drug delivery carriers have limited access to parenchymal resident immune cells compared to small molecules, limiting their efficacy. Nitric oxide (NO) is a potent regulator of vascular and lymphatic transport and a promising candidate for modulating nanocarrier access to LNs, but its lymphatic accumulation is limited by its low molecular weight and high reactivity. In this work, we employ S-nitrosated nanoparticles (SNO-NP), a lymphatic-targeted delivery system for controlled NO release, to investigate the effect of NO application on molecule accumulation and distribution within the LN. We evaluated the LN accumulation, spatial distribution, and cellular distribution of a panel of fluorescent tracers after intradermal administration alongside SNO-NP or a small molecule NO donor. While SNO-NP did not alter total tracer accumulation in draining lymph nodes (dLNs) or affect active cellular transport of large molecules from the injection site, its application enhanced the penetration of nanoscale 30 nm dextrans into the LN and their subsequent uptake by LN-resident lymphocytes, while nontargeted NO delivery did not. These results further extended to a peptide-conjugated NP drug delivery system, which showed enhanced uptake by B cells and dendritic cells when administered alongside SNO-NP. Together, these results highlight the utility of LN-targeted NO application for the enhancement of nanocarrier access to therapeutically relevant LN-resident immune cells, making NO a potentially useful tool for improving LN drug delivery and immune responses.

淋巴结 (LN) 是容纳高浓度淋巴细胞的免疫器官，使其成为多种疾病治疗性免疫调节的关键目标。尽管对靶向 LN 的药物递送非常感兴趣，但与小分子相比，许多纳米级药物递送载体对实质驻留免疫细胞的访问有限，从而限制了它们的功效。一氧化氮 (NO) 是一种有效的血管和淋巴运输调节剂，是调节纳米载体进入 LN 的有希望的候选者，但其淋巴积累受到其低分子量和高反应性的限制。在这项工作中，我们采用 S-亚硝化纳米粒子 (SNO-NP)，一种用于控制 NO 释放的淋巴靶向递送系统，研究 NO 应用对 LN 内分子积累和分布的影响。我们评估了与 SNO-NP 或小分子 NO 供体一起皮内给药后一组荧光示踪剂的 LN 积累、空间分布和细胞分布。虽然 SNO-NP 不会改变引流淋巴结 (dLNs) 中的总示踪剂积累或影响大分子从注射部位的主动细胞转运，但其应用增强了纳米级 30 nm 葡聚糖进入 LN 的渗透以及它们随后被 LN-常驻淋巴细胞，而非靶向 NO 递送则不然。这些结果进一步扩展到肽缀合的 NP 药物递送系统，当与 SNO-NP 一起给药时，该系统显示出 B 细胞和树突细胞的吸收增强。一起，