To synthesize chitosan nanoparticles (CS NPs), ionic gelation is a very attractive method. It relies on the spontaneous supramolecular assembly of cationic CS with anionic compounds, which leads to nanohydrogels. To extend ionic gelation to functionalized CS, the assessment of CS degree of substitution (DS_CS) is a key step. In this paper, we have developed a hyphenated strategy for functionalized CS characterization, based upon ¹H, DOSY and, when relevant, 1D diffusion-filtered ¹⁹F NMR spectroscopies. For that, we have synthesized two series of water-soluble CS via amidation of CS amino groups with mPEG₂₀₀₀-COOH or fluorinated synthons (TFB-COOH). The aforementioned NMR techniques helped to discriminate between ungrafted and grafted synthons and finally to determine DS_CS. According to DS_CS values, the selection of CS–mPEG₂₀₀₀ or CS–TFB copolymers can be made to obtain, in the presence of hyaluronic acid (HA) and tripolyphosphate (TPP), CS–mPEG₂₀₀₀–TPP/HA or CS–TFB–TPP/HA nanohydrogels suitable for drug delivery.

中文翻译：

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聚乙二醇化和氟化壳聚糖的合成与表征：在靶向纳米颗粒药物合成中的应用

为了合成壳聚糖纳米粒子（CS NPs），离子凝胶化是一种非常有吸引力的方法。它依赖于阳离子CS与阴离子化合物的自发超分子组装，从而产生纳米水凝胶。为了将离子凝胶化扩展到功能化的CS，CS取代度（DS _CS）的评估是关键的一步。在本文中，我们基于¹ H，DOSY和相关的1D扩散过滤¹⁹ F NMR光谱学，开发了一种功能化CS表征的联用策略。为此，我们通过用mPEG ₂₀₀₀酰胺化CS氨基合成了两个系列的水溶性CS-COOH或氟化合成子（TFB-COOH）。上述NMR技术有助于区分未嫁接和嫁接合成子，最终确定DS _CS。根据DS _CS值，可以在存在透明质酸（HA）和三聚磷酸盐（TPP）的情况下选择CS–mPEG ₂₀₀₀或CS–TFB共聚物，从而获得CS–mPEG ₂₀₀₀ –TPP / HA或CS–适用于药物输送的TFB–TPP / HA纳米水凝胶。