A novel blue-emitting fluorescent alginate derivative has been successfully synthesised in a simple two-reaction step procedure, using an aqueous conjugation strategy that involved carbodiimide coupling followed by an alkyne-azide "click" reaction. The modified alginate maintained the characteristic ability to form mechanically stable hydrogels by ionic crosslinking. The fluorescent properties of the developed biomaterial were investigated both in solution and hydrogel states, revealing that grafting of the coumarin fluorophore to alginate greatly enhanced its fluorescent properties. Importantly, hydrogels maintained around 80% of their initial fluorescence upon long periods of incubation under physiologic conditions. The fluorescent alginate hydrogels showed to be biocompatible in vitro, supporting the viability, metabolic activity and proliferation of mammary epithelial cells and, more importantly, their morphogenesis into spheroids and polarized acini-like structures. These hydrogels were further applied in the establishment of cell-in-gel microarrays for high-throughput screening of cell behaviour in three-dimensional (3D) matrices, being essential for spotting optimization and analysis. Collectively, our results highlight the potential of coumarin-grafted blue-emitting fluorescent alginate as a valuable tool for biomedical applications where hydrogel tracing is required.

中文翻译：

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香豆素接枝的发蓝光的荧光藻酸盐可作为生物医学应用的潜在有价值的工具。

一种新的发蓝光的荧光藻酸盐衍生物已经成功地通过简单的两步反应步骤合成，使用的水共轭策略涉及碳二亚胺偶联，然后进行炔-叠氮化物的“喀哒”反应。改性藻酸盐保持了通过离子交联形成机械稳定的水凝胶的特征能力。在溶液状态和水凝胶状态下都研究了这种开发的生物材料的荧光特性，揭示了香豆素荧光团嫁接成藻酸盐的能力大大增强了其荧光特性。重要的是，在生理条件下长时间孵育后，水凝胶可保持其初始荧光的80％左右。荧光藻酸盐水凝胶在体外具有生物相容性，支持其生存能力，乳腺上皮细胞的代谢活性和增殖，更重要的是，它们的形态形成为球状体和极化的类腺泡状结构。这些水凝胶进一步用于建立凝胶中细胞微阵列，用于高通量筛选三维（3D）矩阵中的细胞行为，这对于点样优化和分析至关重要。总的来说，我们的结果突出了香豆素接枝的发蓝光的荧光藻酸盐作为需要水凝胶示踪的生物医学应用的宝贵工具的潜力。这些水凝胶进一步用于建立凝胶中细胞微阵列，用于高通量筛选三维（3D）矩阵中的细胞行为，这对于点样优化和分析至关重要。总的来说，我们的结果突出了香豆素接枝的发蓝光的荧光藻酸盐作为需要水凝胶示踪的生物医学应用的宝贵工具的潜力。这些水凝胶进一步用于建立凝胶中细胞微阵列，用于高通量筛选三维（3D）矩阵中的细胞行为，这对于点样优化和分析至关重要。总的来说，我们的结果突出了香豆素接枝的发蓝光的荧光藻酸盐作为需要水凝胶示踪的生物医学应用的宝贵工具的潜力。