School of Chemical Engineering and Research Center for Biophotonics, Chonnam National University, Yong-Bong Ro 77, 61186, Gwangju, Republic of Korea.
Department of Clothing and Textiles, Chonnam National University, Yong-Bong Ro 77, 61186, Gwangju, Republic of Korea.
Mater Sci Eng C Mater Biol Appl. 2020 Feb;107:110323. doi: 10.1016/j.msec.2019.110323. Epub 2019 Oct 22.
Inspired by traditional pH papers, two types of ratiometric fluorescent pH sensors for neutral and alkaline pH ranges were developed in this study by using two fluorescent dyes, coumarin 6 (C6) and nile blue A (NB). These dyes were encapsulated into melamine-formaldehyde (MF) resin particles, which were then incorporated with polymer Nafion (Nf) or polyurethane hydrogel (PU) to prepare pH-sensing membranes. MF-C6 particles immobilized into polymer Nafion (i.e., MF-C6-Nf membrane) showed a dynamic ratiometric pH detection range of 4.5-7.5 through shift in fluorescence emission spectra at acidic and neutral pH solutions, as well as distinct color transition under normal visual sense from pink to yellow color. By contrast, MF-NB particles immobilized into polyurethane hydrogel (i.e., MF-NB-PU membrane) displayed a dynamic ratiometric fluorescence detection range of pH 9 - pH 12 via change in ratiometric fluorescence intensity at two emission band edges. The membrane also showed a clear change from blue to purple color under sunlight at high pH values. These pH-sensing membranes also exhibited high sensitivity, good reversibility, and stability. They were then applied to measure pH values in real urine samples and fermentation media.
受传统 pH 试纸的启发，本研究通过使用两种荧光染料香豆素 6（C6）和尼罗蓝 A（NB），开发了两种用于中性和碱性 pH 范围的比率型荧光 pH 传感器。这些染料被包裹在三聚氰胺-甲醛（MF）树脂颗粒中，然后与聚合物 Nafion（Nf）或聚氨酯水凝胶（PU）结合，制备 pH 感应膜。固定在聚合物 Nafion 中的 MF-C6 颗粒（即 MF-C6-Nf 膜）在酸性和中性 pH 溶液中通过荧光发射光谱的位移显示出动态比率型 pH 检测范围为 4.5-7.5，以及在正常视觉下从粉红色到黄色的明显颜色转变。相比之下，固定在聚氨酯水凝胶中的 MF-NB 颗粒（即 MF-NB-PU 膜）通过两个发射带边缘的比率荧光强度变化显示出动态比率荧光检测范围为 pH 9-pH 12。该膜在高 pH 值下的阳光下还呈现出从蓝色到紫色的明显变化。这些 pH 感应膜还表现出高灵敏度、良好的可逆性和稳定性。然后将它们用于测量实际尿液样本和发酵培养基中的 pH 值。
