Dextran, Biotin, 3000 MW, Lysine Fixable (BDA-3000) - FAQs

View additional product information for Dextran, Biotin, 3000 MW, Lysine Fixable (BDA-3000) - FAQs (D7135)

12 product FAQs found

当我注入荧光葡聚糖时，无法看见神经元的详细结构，如何改善以更好地显示详细的结构？

如果您想看到最精细的结构，应使用低分子量葡聚糖偶联物，例如3,000 MW葡聚糖偶联物。

为什么在固定后，荧光偶联葡聚糖信号没有保留下来？

请确保您使用的是葡聚糖是可固定形式（即包含伯胺）。不包含伯胺的葡聚糖将无法固定。另一个原因可能是葡聚糖的浓度过低，其使用浓度可以增加到10 mg/mL。

右旋糖酐的电荷为多少？

我们没有测定右旋糖酐偶联物的净电荷。净电荷取决于标记右旋糖酐所用的荧光团和制备偶联物所采用的方法。我们根据所用的荧光团将右旋糖酐标记为中性的或阴性的，但是染料和右旋糖酐的净电荷可能并不总是相同。Alexa Fluor、Cascade Blue、荧光黄、荧光素和Oregon Green右旋糖苷本质上是阴性的，而大多数标记两性离子罗丹明 B、四甲基罗丹明和Texas Red染料的右旋糖酐基本上是中性的。

哪种大小的右旋糖酐最适于神经元示踪？

我们已使用过3000至70,000分子量右旋糖酐，但3000至10000分子量右旋糖酐最常用于神经元示踪。3000 分子量的右旋糖酐用于对精细神经传递进行更详细的跟踪、研究间隙连接，并且扩散更快；而10000MW右旋糖酐具有较慢的分散速度、较长的胞内存留时间，且不会不穿过间隙连接。

你们有神经元示踪实验方案吗?

NeuroTrace BDA-10,000 神经元示踪试剂盒（货号N7167）手册有一个 使用10,000 MW lysine-fixable biotin dextran amine（BDA）进行注射操作及神经元跟踪的实验方案。该试验方案也适用于其他荧光标记的右旋糖酐。 请参阅第4和5页的表1a和1b（https://tools.thermofisher.com/content/sfs/manuals/mp07167.pdf）。

我该如何为自己的试验选择示踪对象?

要考虑的因素有示踪对象的大小、给样方式（注射，直接上样到组织等），示踪对象是否需要固定。以下链接详细介绍了我们提供的各类神经元示踪剂的详细信息以及选择方法：

•神经元示踪（https://www.thermofisher.com/us/en/home/life-science/cell-analysis/cell-tracing-tracking-and-morphology/neuronal-tracing.html）
•选择示踪剂（https://www.thermofisher.com/us/en/home/references/molecular-probes-the-handbook/fluorescent-tracers-of-cell-morphology-and-fluid-flow/choosing-a-tracer.html）
•成像分析（http://assets.thermofisher.com/TFS-Assets/BID/Reference-Materials/bioprobes-50-journal.pdf）

I can't see the structural details of neurons when I inject my fluorescent dextran. What can I do to improve the detailed structure?

If you want to see the most detailed structure you should use the low molecular weight conjugated dextrans such as the 3,000 MW dextrans.

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

Why isn't my fluorescently conjugated dextran signal retained after fixation?

Ensure that the dextran you are using is the fixable form (i.e., contains a primary amine). Dextrans that do not contain a primary amine will not be fixed. Another factor could be that the concentration of the dextran is too low, and the concentration use can be increased up to 10 mg/mL.

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

What are the charges of the dextrans?

We do not determine the net charge of the dextran conjugates. The net charge depends on the fluorophore used to label the dextran and the method of preparing the conjugate. We label some dextrans as neutral or anionic based on the fluorophore used, however the net charge of the dextran may not always be the same as the dye. The Alexa Fluor, Cascade Blue, Lucifer Yellow, fluorescein, and Oregon Green dextrans are intrinsically anionic, whereas most of the dextrans labeled with the zwitterionic Rhodamine B, tetramethylrhodamine and Texas Red dyes are essentially neutral.

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

What size dextran is best for neuronal tracing?

Dextrans with molecular weights from 3,000 to 70,000 have been used, however the 3,000 and 10,000 MW dextrans are most commonly used for neuronal tracing. The 3,000 MW dextrans are used for more detailed tracing of fine neuronal projections, investigating gap junctions, and diffuse more quickly; while the 10,000 MW dextrans have slower distribution, longer cellular retention, and do not cross gap junctions.

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

Do you have a neuronal tracing protocol?

The NeuroTrace BDA-10,000 Neuronal Tracer Kit (Cat. No. N7167) manual has a good protocol for injection procedures and neuronal tracing using the10,000 MW lysine-fixable biotin dextran amine (BDA). This protocol could potentially be applied to other fluorescent dextrans.

Please review Tables 1a and 1b on pages 4 and 5 - https://tools.thermofisher.com/content/sfs/manuals/mp07167.pdf

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

How do I know which tracer to choose for my experiment?

Factors to consider are size of tracer, method of delivery (injection, direct application to tissue, etc.), and if the tracer needs to be fixable. Here are some links to details about the various classes of neuronal tracers we offer and how to choose between them:

Neuronal Tracing (https://www.thermofisher.com/us/en/home/life-science/cell-analysis/cell-tracing-tracking-and-morphology/neuronal-tracing.html)
Choosing a Tracer (https://www.thermofisher.com/us/en/home/references/molecular-probes-the-handbook/fluorescent-tracers-of-cell-morphology-and-fluid-flow/choosing-a-tracer.html)
Imaging Analysis (http://assets.thermofisher.com/TFS-Assets/BID/Reference-Materials/bioprobes-50-journal.pdf)

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.