荧光探针与分析物作用可引起光学信号的改变。化学传感与成像分析相结合具有高灵敏度、高时空分辨能力的特点，广泛应用于化学、生物医学等领域。近红外荧光探针因激发波长长，可避免对活体细胞的损伤和背景干扰，在细胞分析中有明显的优势和应用潜力。本项目拟合成可用于活细胞成像的近红外硅基pH荧光探针。设计制备一系列新型近红外苯乙烯类菁染料(SCYs)，采用改进的St?ber法合成硅基为载体的具有核壳结构的SCYs/SiO2 纳米近红外pH荧光探针，研究苯乙烯类菁染料掺杂的硅基纳米颗粒的制备理论和技术。基于荧光光谱技术测定pKa值、pH响应范围、灵敏度、可逆性、细胞毒性等，结合激光共聚焦扫描显微技术研究其在活细胞中的H+荧光成像，评价细胞膜通透性和细胞共定位性。近红外硅基pH荧光探针为研究细胞内pH变化提供一种重要的实时监测分析方法，从分子水平认识生命过程及探索重大疾病发生机制具有重要意义。

Chemical sensing and imaging analysis with changes in optical signal from optical probe and analyte have high sensitivity and high temporal and spatial resolution. They are widely used in the fields of chemistry and biomedicine etc. Near infrared fluorescent probe with longer excitation wavelength can avoid damage of live cells and interference from cellular background and exhibit obvious advantages and potential application. The aim of project is to synthesize a series of novel near infrared silica-based pH fluorescent probes toward imaging in live cells. A series of near infrared styrylcyanine (SCYs) dyes are designed and prepared. The silica-based nano-fluorescent probe SCYs/SiO2 with core-shell structure is synthesized by improved St?ber technique.The theory and technique of synthesis about SYN dopped silica-based nanoparticle were studied. Many parameters including pKa, pH response range, sensitivity, reversibility etc. are determined based on fluorimetry.Further application of fluorescent imaging in live cells is investigated by laser scanning confocal microscopic technique. The cell membrane permeability and colocalization are estimated. Near infrared silica-based pH fluorescent probe provides an important analytical method with real time detection for pH change in cells. It will be great significance to understand life process in molecular level and explore mechanism of fatal disease.