利用鑭系金屬離子與2-噻吩甲酰三氟丙酮調控明膠/海 藻酸水凝膠之結構與性質於感測應用

Abstract

鑭系金屬配合物具有優異的光學特性（例如高純色度、大斯托克斯位移和長生命期），因此，含鑭系金屬的發光水凝膠是感測應用的理想材料。本研究採用海藻酸二醛 (ADA) 和苯基硼酸-聚乙烯亞胺接枝明膠 (PPG)，以及鑭系元素 (Ln3+) 離子（釤 (III) (Sm3+)、銪 (III) (Eu3+) 和铽 (III) (Tb3+)），合成了具有三重化學交聯的 PPG/ADA-Ln3+ 水凝膠。 在第一個研究中，PPG/ADA-Ln3+ 水凝膠網絡中具有三個動態交聯鍵，包括亞胺鍵、硼酸酯鍵和鑭系金屬配位鍵。研究結果顯示，透過改變鑭系元素的類型可以微調 PPG/ADA-Ln3+ 水凝膠的結構和性能（發光、流變、機械強度、膨潤能力和穩定性），其中較小的鑭系元素離子有助於增強水凝膠網絡的機械性能。這可能是因為較小的Tb³⁺ 離子的加入有助於形成更緻密的網絡，這不僅可以增強機械性能，還可以提高感測性能。線性區別分析 (LDA) 分析證明了 PPG/ADA-Ln3+ 水凝膠表現出顯著區分揮發性有機化合物中酸性和鹼性蒸氣的能力，該能力被進一步研究用於細菌感測上。綜上所述，我們系統性地研究了鑭系離子半徑的影響對PPG/ADA-Ln3+水凝膠結構、機械性質、感測能力的影響，並且證實PPG/ADA-Ln3+水凝膠在透過發光變化感測揮發性有機化合物和細菌方面的潛在應用。 在第二個研究中，進一步引入有機配體2-噻吩甲醯三氟丙酮（TTA）與Ln3+離子配位， TTA的引入增強了PPG/ADA-Ln3+水凝膠的發光強度，使得PPG/ADA-Ln3++TTA水凝膠成為可以透過發光變化感測揮發性有機化合物的更好材料。總體來說，本篇論文的研究開發了一系列含鑭系金屬的發光水凝膠，可藉由金屬離子以及有機配體調控含鑭系金屬水凝膠的結構、性質、感測性能。

Luminescent lanthanide-containing hydrogels were ideal materials for sensing applications due to the outstanding optical properties of lanthanide complexes (e.g., high color purity, large Stokes shift, and long lifetime). In this study, alginate dialdehyde (ADA) and phenylboronic acid-polyethyleneimine modified gelatin (PPG), along with the lanthanide (Ln3+) ions (i.e., samarium (III) (Sm3+), europium (III) (Eu3+), and terbium (III) (Tb3+)), were used to synthesize PPG/ADA-Ln3+ hydrogels. In the first project, the three dynamic crosslinks in the PPG/ADA-Ln3+ hydrogel networks included imine, boronate ester, and coordination bonds. The results showed that the structures and properties (i.e., luminescence, rheological behavior, mechanical strength, swelling capacity, and stability) of PPG/ADA-Ln3+ hydrogels can be precisely adjusted through altering the types of lanthanides ions used, Notably, the incorporation of smaller lanthanide ions was found to enhance the mechanical properties of the hydrogel network. This can be attributed to the incorporation of smaller Tb³⁺ ions, which facilitates the formation of denser networks that not only enhance mechanical properties but also improve sensing performance. The PPG/ADA-Ln3+ hydrogels also exhibit a notable ability to distinguish acidic and basic vapors within volatile organic compounds, as demonstrated through linear discriminant analysis (LDA), a capability that is further investigated for the differentiation of bacterial species. Taken together, we not only systematically investigated the impact of the radius of lanthanide ions on the structure, mechanical properties, and the ability of sensing ability of PPG/ADA-Ln3+ hydrogels, but also demonstrated the potential application of PPG/ADA-Ln3+ hydrogels in sensing volatile organic compounds and bacteria through luminescence changes. In the second project, the organic ligand 2-thenoyltrifluoroacetone (TTA) was further introduced to coordinate Ln3+ ions. With TTA, the intensity of luminescence spectra of PPG/ADA-Ln3++TTA hydrogels was enhanced, making PPG/ADA-Ln3++TTA hydrogels a better material for sensing volatile organic compounds (VOCs) through luminescence changes. Overall, the study developed a series of lanthanide-containing hydrogels through the fine-tuning of structure, properties, and sensing ability using metal ions and organic ligands.