中文摘要：

基于再沉淀方法制备了一种具有比率荧光发射的纳米水凝胶,适用于检测生理范围的pH值。通过在聚氨酯水凝胶中引入pH值指示剂以及具有共振能量传递关系的荧光染料分子,赋予原本非pH响应和非荧光型的水凝胶以pH探测能力。随着pH值由酸性渐变为碱性,纳米水凝胶的绿色荧光强度逐渐增强,而红色荧光逐渐减弱。所制备的纳米水凝胶由于具有灵敏度高、亲水性好、稳定性好、响应快以及pH值检测范围恰好涵盖了生理pH值范围（pH值6～8）等优点,因此在细胞内pH值探测领域具有广阔应用前景。

英文摘要：

In this paper a ratiometric fluorescence nanogel was prepared and used in pH sensing.By introducing a pH probe and two fluorescent dyes（related by fluorescent resonant energy transfer）,the non-responsive and non-fluorescent hydrogel（polyurathane） was imparted the ability of pH sensing.With the increase of pH value from acidic to basic,the dominant fluorescence of nanogels varieds from red to green accordingly.The as-prepared nanogels exhibits high sensitivity,high hydrophilicity,quick responsiveness,and physiological pH detecting in the range of 6 ～ 8.Hence,the nanogels would be very potential as intracellular pH nanosensors.