Clear Kasey J, Virga Katelyn, Gray Lawrence, Smith Bradley D
Department of Chemistry and Biochemistry, 236 Nieuwland Science Hall, University of Notre Dame, Notre Dame, Indiana 46556, United States.
J Mater Chem C Mater. 2016 Apr 14;4(14):2925-2930. doi: 10.1039/C5TC03480A. Epub 2015 Dec 1.
Liposomes containing membrane-anchored pH-sensitive optical probes are valuable sensors for monitoring pH in various biomedical samples. The dynamic range of the sensor is maximized when the probe p is close to the expected sample pH. While some biomedical samples are close to neutral pH there are several circumstances where the pH is 1 or 2 units lower. Thus, there is a need to fine-tune the probe p in a predictable way. This investigation examined two lipid-conjugated optical probes, each with appended deep-red cyanine dyes containing indoline nitrogen atoms that are protonated in acid. The presence of anionic phospholipids in the liposomes stabilized the protonated probes and increased the probe p values by < 1 unit. The results show that rational modification of the membrane composition is a general non-covalent way to fine-tune the p of an optical liposome sensor for optimal pH sensing performance.
含有膜锚定pH敏感光学探针的脂质体是用于监测各种生物医学样品中pH值的有价值的传感器。当探针p接近预期样品pH值时，传感器的动态范围最大化。虽然一些生物医学样品接近中性pH值，但在几种情况下pH值会低1或2个单位。因此，需要以可预测的方式微调探针p。本研究考察了两种脂质共轭光学探针，每种探针都附加了深红色花菁染料，其中含有的吲哚啉氮原子在酸性条件下会质子化。脂质体中阴离子磷脂的存在稳定了质子化探针，并使探针p值增加了不到1个单位。结果表明，合理修饰膜组成是一种通用的非共价方法，可用于微调光学脂质体传感器的p值，以实现最佳pH传感性能。
