FluoSpheres™ Carboxylate-Modified Microspheres, 0.1 μm, yellow-green fluorescent (505/515), 2% solids, 10 mL - FAQs

View additional product information for FluoSpheres™ Carboxylate-Modified Microspheres - FAQs (F8781, F8782, F10720, F8799, F8810, F8811, F8812, F8794, F8795, F8797, F8819, F8813, F8814, F8815, F8816, F20881, F8792, F8793, F8820, F8787, F8821, F8789, F8800, F8823, F8801, F8783, F8784, F8786, F8806, F8807, F8809, F8824, F8803, F8825, F8826, F8827, F8805)

34 product FAQs found

洗涤和离心后，我的微球只留下了极少量的沉淀且溶液呈透明状。为什么会出现这种现象？

离心并不是收集较小微球的有效方法；即使可以看到小沉淀，仍有不少微粒残留在溶液中。对于直径低于1 µm的微珠，我们建议采用以下任一方法来洗涤：

•错流式过滤，因为这些微粒压缩系数极高并可抵抗较高重力而无损伤风险
•采用500 kDa MWCO截留分子量透析

注：直径大于>1 µm的微球可在1,300 rpm下离心。

我的微球已保存超过一年，我想知道它们是否仍可正常使用，有什么好办法来核实它们的功能是否完好？

细菌污染是造成微球失效的最常见原因。我们的许多微粒附带低水平的叠氮化钠来防止细菌污染，但有时仍难免出现污染。评估细菌污染的最好方法是将微球铺到适当的生长培养基上，在72小时后检查细菌生长情况。

我不慎冷冻了自己的微球，还可继续使用么？

即使短时间冷冻也会导致不可逆的聚集，并可能造成微球变形，不可继续使用。

在我的实验体系中，蛋白包被的微球出现非特异性结合。有什么产品可以帮助减少这些非特异性作用吗？

非特异性结合可通过封闭液来缓解，但微球封闭需要比市面上大多数常见封闭液更强效的封闭液。为此我们研发了BlockAid封闭液（货号B10710）。这是一种基于蛋白的封闭液试剂，专用于偶联生物素，链霉亲和素、NeutrAvidin生物素结合蛋白或其他蛋白的FluoSpheres微球和TransFluoSpheres 微球。事实证明，BlockAid封闭液在各类流式细胞术、显微检测以及微阵列应用中有助于减少蛋白或其他大分子包被微球的非特异性结合。

我应该使用哪种方法来分散聚集体？

我们推荐使用水浴超声仪来分散聚集体。不要使用探头超声仪，否则会损伤微球。

我按照实验方案建议的方法超声处理羧酸盐修饰的乳胶微球，结果发现溶液中出现泡沫，需要特别注意吗？

泡沫是由Tween 20造成的，后者在储液中起到防止聚集的作用。在这种试剂中存在泡沫很正常。

我可以离心自己的荧光微球么？

直径>1 µm的微球可以在1,300 rpm下离心。离心并不是收集较小的微球的有效方法；对于直径<1 µm的微珠，我们建议用错流过滤或500 kDa MWCO截留分子量透析方法洗涤。

我应该使用哪种微球来测定局部血流量？如何进行这一操作步骤？

我们提供多种专用于血流量测定的FluoSphere 微球和试剂盒；如果我们提供的颜色和/或粒径不符合您的需求，我们建议在血流量测定过程中使用羧基修饰的珠子。我们在用于示踪研究的FluoSpheres 荧光微球产品手册中提供了一些基本的使用指南。另外，西雅图的华盛顿大学的荧光微球资源中心（FMRC）网站（http:///fmrc.pulmcc.washington.edu/fmrc.shtml）上提供有使用荧光微球评估局部血流量的详细应用手册和参考文献。

我应该选择哪种微球产品完成点扩散函数？

点扩散函数需要高分辨率微球，我们有两种可用于此用途的高分辨率微球。TetraSpeck微球，0.1 µm（货号T7279）是单一的高分辨率微球，同时带有蓝、绿、橙和暗红染料。PS-Speck Microscope Point Source Kit（货号P7220）则包含单独染色的蓝、绿、橙和暗红荧光微球，直径约175 nm。

对于荧光聚苯乙烯微球，我应该使用哪种封片剂？

我们建议使用ProLong产品或其他水相封片剂，应该避免有机成分封固剂，如基于二甲苯的封片剂。

FluoSpheres微球不含表面活性剂吗？

FluoSpheres微球可能含有微量的表面活性剂。仅仅直径> 100 nm 的IDC Latex微球完全不含表面活性剂。

我希望把微球放入非水溶液中；它们会在醇类中反应么？

其在醇类或水/醇类混合物中的稳定性取决于醇类的链长。微珠在40%的甲醇中相当稳定，但是它们在长链醇类中会更容易溶解。微珠在含有醇类的溶剂中长时间储存会导致染料的溶出。

我注意到你们大多数微球产品中含有叠氮化钠，但是我的应用过程中不能含有叠氮化钠，如何从微球溶液中除去叠氮化钠？

我们建议使用500,000 MWCO截留分子量透析的方法从含有微球的缓冲液中除去叠氮化钠。

在单个荧光微球中有多少染料分子？

我们没有测定过每个微球中染料分子的具体数目。染料分子数目是一个与微粒直径和染料性质相关的变量。

怎样用染料标记FluoSpheres微球？

在含有疏水染料（专用于特定的FluoSpheres产品）的溶液中，聚苯乙烯微球会在膨胀。之后，此染料能够扩散到聚苯乙烯基质中。然后微球从溶剂中移除并透析进入到水相环境，反相膨胀并将染料嵌入聚苯乙烯。染料嵌入聚苯乙烯后，会与外界环境妥善地隔离。标记的具体实验方案和疏水性染料的成分是我们的专利技术。

I have some FluoSpheres polystyrene microspheres, with 20 nm diameter. They are aggregating a lot. What can I do about it?

The smaller the microspheres, the greater the propensity to aggregate. But the aggregation is not irreversible. Sonicate in a bath sonicator or vortex to disperse, just prior to use. You can also add a small concentration of Tween-20 or Triton X-100 (unless you are using them in a live-cell system).

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

I sonicated my 2.0 µm carboxylate-modified microspheres, as recommended, but saw foaming (bubbles) on top of the solution. Should I be concerned?

Use of a bath sonicator is recommended to help break up any aggregated microspheres. The foaming is from Tween-20, which is in the stock solution to help prevent aggregation. It is normal and expected to see bubbles from this. Do not use a probe sonicator, which would cause damage to the microspheres (as well as much more bubbling).

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

When does the warranty guarantee expire for FluoSpheres Carboxylated-Modified Microspheres?

FluoSpheres Carboxylate-Modified Microspheres (Cat. Nos. F8783, F8786, F8801, F8807, F8811, F8803, F8816, F8823, F20881, F10720) have a 1-year warranty guarantee, unless otherwise indicated on the Certificate of Analysis (COA).

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

What is the warranty for FluoSpheres microspheres?

The warranty period for FluoSpheres microspheres is 1-year from the date of shipment.

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

After washing and centrifugation, there was only a very small pellet left of my microsphere beads and the solution was transparent. Why is this?

Centrifugation is not an effective way to collect smaller microspheres; many particles remain in the solution even if you can visualize a small pellet. For beads less than 1 µm in diameter, we recommend washing by either:

Cross-flow filtration, as these particles have a very high compression modulus and can withstand high g-forces without risk of harm or dialysis with a 500 kDa MWCO
Note: Microspheres greater than 1 µm in diameter can be centrifuged at 1,300 rpm.

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

I've had my microspheres for over a year, and I'm wondering if they're still good to use. What are some good ways to check their functionality?

Bacterial contamination is the most common cause of microspheres becoming unusable. Many of our particles are supplied with a low level of sodium azide to prevent bacterial contamination, but sometimes this can still occur. Bacterial contamination is best assessed by plating on appropriate growth medium and checking the plates after 72 hr.

Find additional tips, troubleshooting help, and resources within ourMicrospheres Support Center.

I accidentally froze my microspheres; can I still use them?

Even brief freezing can cause irreversible aggregation and potential distortion of the bead shape. You should not use these microspheres.

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

My protein-coated microspheres appear to be non-specifically binding in my experimental system. Do you have a product that can help reduce these non-specific interactions?

Non-specific binding can often be relieved by a blocking solution, but microspheres seem to require a stronger blocking solution than those most commonly commercially available. Hence, we've developed the BlockAid Blocking Solution (Cat. No. B10710). This reagent is a protein-based blocking solution designed for use with FluoSpheres microspheres and TransFluoSpheres microspheres conjugated to biotin, streptavidin, NeutrAvidin biotin-binding protein, or other proteins. The BlockAid Blocking Solution has proven useful for reducing the nonspecific binding of protein-coated or other macromolecule-coated microspheres in a wide variety of flow cytometry, microscopy, and microarray applications.

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

What sort of sonication method should I use to disperse microsphere aggregates?

We recommend using a bath sonicator to disperse microsphere aggregates. Do not use a probe sonicator as this will damage the microspheres.

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

I sonicated my carboxylate-modified latex microspheres as recommended in the protocol, and I saw foaming in the solution. Should I be concerned?

The foaming is from Tween 20, which is present in the stock solution to help prevent aggregation. It is normal to see bubbles from this reagent.

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

Can I centrifuge my fluorescent microspheres?

Microspheres greater than 1 µm in diameter can be centrifuged at 1,300 rpm, but once pelleted they may not disperse readily or not at all. Centrifugation is not an effective way to collect smaller microspheres; for beads less than 1 µm in diameter, we recommend washing by either cross-flow filtration or dialysis with a 500 kDa MWCO.

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

Which microspheres should I use to measure regional blood flow? How do I perform these procedures?

We offer a variety of FluoSphere microspheres and kits specifically designed for blood flow determination; if the available colors and/or sizes do not suit your needs, we recommend using beads modified with carboxylate groups for blood flow determination applications. We give some basic usage guidelines in the FluoSpheres Fluorescent Micospheres for Tracer Studies product manual (https://tools.thermofisher.com/content/sfs/manuals/mp13080.pdf). Additionally, the University of Washington Seattle offers the Fluorescent Microsphere Resource Center (FMRC) website (http://fmrc.pulmcc.washington.edu/fmrc.shtml) with detailed applications manuals and references for using fluorescent microspheres to evaluate regional blood flow.

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

What microsphere product should I select to perform a point spread function?

Point spread functions will require a subresolution bead, and we have two different subresolution bead products that could be used for this purpose. TetraSpeck Microspheres, 0.1 µm (Cat. No. T7279), are single subresolution microspheres that are simultaneously stained with blue, green, orange, and dark red dyes. The PS-Speck Microscope Point Source Kit (Cat. No. P7220) consists of individually-stained blue, green, orange, and dark red fluorescent microspheres that are approximately 175 nm in diameter.

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

What sort of mounting media should I use for fluorescent polystyrene microspheres?

We recommend using a ProLong product or any other aqueous mounting media. You should avoid organic-based mountants such as toluene-based mounting media.

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

Are the FluoSpheres microspheres surfactant-free?

The FluoSpheres microspheres may have a trace amount of surfactant. Only IDC Latex beads with diameters greater than 100 nm are actually surfactant-free.

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

I want to put my microspheres in something besides water; how will they react in alcohol?

The stability in alcohol or water/alcohol mixtures is dependent on the alcohol chain length. The beads are fairly stable in 40% methanol, but they will dissolve much more readily in long chain alcohols. Prolonged storage of beads in an alcohol containing solution will tend to leach out the dye.

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

I noticed that many of your microsphere products have sodium azide present, but I can't have sodium azide in my application. How should I remove sodium azide from the microsphere solution?

We recommend using dialysis with a MWCO of approximately 500,000 to remove the sodium azide from the microsphere-containing buffer.

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

How many dye molecules are there in a single fluorescent microsphere?

We do not determine the exact number of dye molecules per microsphere. The number of dye molecules is a function of the diameter of the particle and the properties of the dye.

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

How do you label the FluoSpheres microspheres with dye?

The polystyrene microspheres are swelled in a solvent containing a hydrophobic dye specific to the FluoSpheres product. The dye is then able to diffuse into the polystyrene matrix. The beads are then removed from the solvent and dialyzed into an aqueous environment; this reverses the swelling and traps the dye in the polystyrene. Once trapped, the dye is fairly protected from the external environment. The exact protocol and identity of the hydrophobic dyes are proprietary.

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