当我分析click标记样品时,观测到较高的本底干扰,这是什么原因所致?如何减少本底干扰?
click反应在叠氮化物和炔烃类间是非常有选择性的。生物体系不可能有其他副反应。任何非特异性本底都是由于染料和多种细胞组件的非共价结合造成的。在click反应后,Select FX信号增强剂在减少染料非特异性电荷连接方面的作用失效;我们不推荐将其与Click-iT检测试剂一同使用。减少本底干扰的最佳方法是增加BSA洗涤的次数。您应始终在同等的处理和检测条件下做无染料或无click反应对照,以证实本底确系染料而非自发荧光所致。此外,您还可在无EdU 或无-EU,仅含溶剂的对照样本上进行完整的click反应,验证click反应信号的特异性。
我用了一种神经元特异性抗体标记我的神经元,怎样才能减少非特异性抗体结合?
•需要进行封闭操作以减少由非特异性抗体结合产生的背景荧光。常用的封闭步骤是加入2-5%牛血清白蛋白(fraction V defatted BSA)溶液。另一种方法是采用5-10%二抗种属来源的血清溶液。例如,使用山羊抗小鼠IgG二抗时,样品可以被5-10%正常山羊血清有效封闭。为了进一步减少背景荧光,可以使用Image-iT FX 信号增强剂作为预封闭步骤,减少由偶联物上的染料和细胞组分之间电荷的相互作用引起的非特异性标记。
•如果您使用二抗,确保抗体的种属与样品不同。例如不要对小鼠组织使用抗小鼠二抗。
•滴定测定抗体浓度,使用能获得充足的信号的最低浓度。
•试试荧光标记的一抗,因为它应会降低背景干扰,但这样做也会降低信号强度。
我在对照细胞的细胞核和线粒体中看到非特异性结合,但是蛋白质结合不足以将其终止。我应该怎么做?
这种二抗非特异性结合的现象可能是由染料电荷引起的,例如带负电荷的染料被带正电荷的细胞组分吸引。为了阻止该现象,使用Image-iT FX Signal Enhancer(货号I36933和R37107)能够抑制结合物上的染料与细胞组分之间的电荷作用,进而阻断非特异性结合。
I used Image-iT FX Signal Enhancer solution to get rid of nonspecific nuclear labeling with Alexa Fluor 568 secondary antibody, but I also saw a significant reduction in my specific mitochondrial antibody labeling. Why is this and what can I do?
The Image-iT FX Signal Enhancer reduces non-specific binding of dye conjugates by blocking positively-charged areas of cells or tissues that attract negatively-charged dyes. In cells after fixation, some positively-charged structures are the nuclei and mitochondria. Thus, you would expect to see a reduction in both mitochondrial and nuclear signal. The lower signal you see afterward is the specific mitochondrial signal; the fluorescence that was lost was the non-specific labeling.
Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.
Can I use the Image-iT FX Signal Enhancer instead of my normal blocking solution (BSA or serum)?
No. Image-iT FX Signal Enhancer is not a protein blocker, like BSA, normal serum, or other commercial antibody blockers. Use it as a separate step to block non-specific charge-based binding of dyes to cellular components.
Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.