Lanthanide doped upconversion luminescent nanoparticles (UCNPs) have drawn widely attention in biomedical research. The generally synthesized oleate capped UCNPs have no aqueous dispersibility so that surface modification is required to be water dispersible. Herein, we developed an easy‐going but effective approach to prepare hydrophilic UCNPs based on oxidized alginate molecule (OAlg). After surface modification treatment, the OAlg modified UCNPs (UCNPs‐OAlg) shows excellent dispersibility and longer stability in aqueous solution even after 180 days. After incubation with UCNPs‐OAlg, the upconversion luminescent images of living Hela cells were clearly obtained. It indicated that oxidized alginate modified UCNPs can be candidate for excellent imaging probes in future.

中文翻译：

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氧化海藻酸盐对镧系元素掺杂上转换纳米粒子的长期稳定表面改性方法

镧系元素掺杂的上转换发光纳米颗粒（UCNPs）在生物医学研究中引起了广泛关注。通常合成的油酸酯封端的UCNP不具有水分散性，因此需要表面改性为水分散性。本文中，我们开发了一种简便易行但有效的方法来基于氧化藻酸盐分子（OAlg）制备亲水性UCNP。经过表面改性处理后，即使在180天后，OAlg改性的UCNPs（UCNPs-OAlg）仍具有出色的分散性和更长的水溶液稳定性。与UCNPs-OAlg孵育后，清晰获得了活Hela细胞的上转换发光图像。这表明氧化的藻酸盐修饰的UCNPs将来可能成为出色的成像探针的候选者。