Effects of temperature on calcium-sensitive fluorescent probes
Effects of temperature on calcium-sensitive fluorescent probes
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DOI：
10.1016/s0006-3495(00)76758-0
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发表时间：
2000-04-01
影响因子：
3.4
通讯作者：
Crowe, JH
中科院分区：
文献类型：
--
作者：
Oliver, AE;Baker, GA;Crowe, JH
温度对钙敏感染料结合平衡的影响已被广泛研究，但在染料的光物理中也有与温度有关的重要变化，这些变化在很大程度上被忽略了。我们系统地研究了五种钙敏感染料在钙饱和和无钙条件下的热效应。Quin-2、金霉素、钙绿葡聚糖、Indo-1和Fura-2在所测试的全部或部分范围(5-40摄氏度)内都显示出对荧光的温度依赖效应。具体地说，在低温下，单波长染料的强度增加。由于在两个波长上的不同影响，比率计量型染料通常表现出荧光比率随着温度的降低而降低。粘度、pH、氧猝灭或荧光最大值的变化不能完全解释温度对荧光的影响。用多频相位调制荧光法测定了这些染料在有钙和无钙条件下的激发态寿命。在大多数情况下，低温会导致荧光寿命延长。低温下寿命的延长很可能是温度对钙敏感染料物理性质的影响的主要原因。显然，这些温度效应会影响报告的钙浓度，因此在任何涉及可变温度的调查中都必须考虑到这一点。
The effect of temperature on the binding equilibria of calcium-sensing dyes has been extensively studied, but there are also important temperature-related changes in the photophysics of the dyes that have been largely ignored. We conducted a systematic study of thermal effects on five calcium-sensing dyes under calcium-saturated and calcium-free conditions. Quin-2, chlortetracycline, calcium green dextran, Indo-1, and Fura-2 all show temperature-dependent effects on fluorescence in all or part of the range tested (5-40 degrees C). Specifically, the intensity of the single-wavelength dyes increased at low temperature. The ratiometric dyes, because of variable effects at the two wavelengths, showed, in general, a reduction in the fluorescence ratio as temperature decreased. Changes in viscosity, pH, oxygen quenching, or fluorescence maxima could not fully explain the effects of temperature on fluorescence. The excited-state lifetimes of the dyes were determined, in both the presence and absence of calcium, using multifrequency phase-modulation fluorimetry. In most cases, low temperature led to prolonged fluorescence lifetimes. The increase in lifetimes at reduced temperature is probably largely responsible for the effects of temperature on the physical properties of the calcium-sensing dyes. Clearly, these temperature effects can influence reported calcium concentrations and must therefore be taken into consideration during any investigation involving variable temperatures.