In this study, the sulfated polysaccharide (SP) of Codium fragile was conjugated to folic acid (SP-FA). FT-IR and ¹H NMR techniques revealed the occurrence of esterification reaction between the hydroxyl group of SP and the γ–carboxyl group of FA that confirming the SP-FA formation. SP and SP-FA did not show any direct toxicity effect on NK cells and HeLa cells. However, the treatment of SP and SP-FA enhance the NK cells cytotoxicity against HeLa cells by the upregulation of IFN-γ, TNF-α, perforin, and Granzyme-B. Moreover, NK cells activation was stimulated through NF-кB and MAPK pathways. The binding capacity studies exposed the targeting ability of HeLa cells by folate receptor (FR) which was assessed by a confocal quantitative image cytometer analysis. These results indicate that SP-FA could be used as selective drug delivery systems for targeting FR-overexpressed cancer cells with less toxicity.

在这项研究中，脆弱的钴的硫酸化多糖（SP）与叶酸（SP-FA）共轭。FT-IR和¹1 H NMR技术揭示了SP的羟基和FA的γ-羧基之间发生了酯化反应，这证实了SP-FA的形成。SP和SP-FA对NK细胞和HeLa细胞没有直接的毒性作用。但是，SP和SP-FA的处理通过上调IFN-γ，TNF-α，穿孔素和Granzyme-B来增强NK细胞对HeLa细胞的细胞毒性。此外，NK细胞活化是通过NF-кB和MAPK途径刺激的。结合能力研究通过叶酸受体（FR）暴露了HeLa细胞的靶向能力，而叶酸受体是通过共聚焦定量图像细胞仪分析来评估的。这些结果表明，SP-FA可用作选择性药物递送系统，以较低的毒性靶向FR过表达的癌细胞。