Polystyrene microspheres present a flexible platform for applications in diagnostics and bioseparations. They may be coated with recognition molecules, such as antibodies, antigens, peptides, or nucleic acid probes, and can be loaded with hydrophobic dyes and other compounds. Unmodified polymer spheres also find extensive use as standards for instrument set-up and calibration. Available in diameters ranging from 20nm to 200µm, products exhibit excellent size uniformity.
聚苯乙烯微球为诊断和生物分离应用提供了一个灵活的平台。它们可以涂有识别分子，例如抗体、抗原、肽或核酸探针，并且可以装载疏水性染料和其他化合物。未改性的聚合物球也广泛用作仪器设置和校准的标准。产品的直径范围从 20nm 到 200µm，具有出色的尺寸均匀性。
Plain polystyrene microspheres are ideal for protein adsorption, and have been utilized in a range of diagnostic tests and assays. Surface modified microspheres are available with carboxyl or primary amine groups for covalent ligand attachment. Affinity binding systems offer simple and efficient ligand attachment. Coatings of Fc binding proteins are able to orient antibodies for optimal activity, and streptavidin offers extremely stable attachment of biotinylated molecules, such as proteins, peptides, and oligonucleotides.
普通聚苯乙烯微球是蛋白质吸附的理想选择，并已用于一系列诊断测试和分析。表面改性的微球具有羧基或伯胺基，用于共价配体连接。亲和结合系统提供简单有效的配体连接。Fc 结合蛋白涂层能够使抗体定向以获得最佳活性，而链霉亲和素可提供极其稳定的生物素化分子附着，例如蛋白质、肽和寡核苷酸。
Product Data Sheet 702
DESCRIPTION
Bangs Laboratories offers uniform, non-porous silica (SiO2
) microspheres available in nominal diameters of ~150nm-8µm. These particles typically have size
CVs of 10-15%.
Inorganic supports such as silica microspheres have become increasingly important for a variety of applications, including isolation of nucleic acids, cell
separation, and immuno- and DNA-based assays. They offer the combined benefits of a broad platform and the unique properties of a silica substrate:
• Flexible silanization chemistries
• Unique refractive index and density
• Low autofluorescence
• Low nonspecific binding of many biomolecules
• Hydrophilicity
• Ease of handling
CHARACTERISTICS
Composition: SiO2, nonporous
Surface Groups: SiOH (non-functionalized); NH2
or COOH; streptavidin
Refractive Index: ~1.43-1.46 (589nm)
Density: 2.0 g/cm3
Glass Transition Temp: >>1000˚C*
* Reported value for bulk silica.
NOTES
1. Aggregation: If observed, aggregation may be treated using sonication (bath sonicator, ~10 minutes; probe sonicator, ~1 minute). See also TechNote
202, Microsphere Aggregation.
2. Washing: Standard washing methodologies are recommended, i.e. centrifugation where practicable, and dialysis or filtration for microspheres
<500nm. See TechNote 203, Washing Microspheres. Please note that carboxyl (COOH) or amine (NH2
) surface groups (from silane) will equilibrate with
those in the suspending solution. It is therefore expected that some amount of surface groups will be removed with each aqueous wash.
3. Transitioning Microspheres into a Solvent and Drying: Silica microspheres >0.5µm in diameter may be dried to a powder. To dehydrate the
surface (removed adsorbed water), the microspheres should first be washed with an organic solvent, such as ethanol or THF. Researchers should then
begin by transitioning the microspheres from an aqueous buffer to solutions of increasing solvent concentration, and then separating them from solution
(via settling, centrifugation, or filtration). The microspheres are then dried from a moist cake, either in the open air or in a drying oven (e.g. 24 hours at
70˚C). The dry cake may be crushed to a powder with a mortar and pestle. Dried powder will be extremely hygroscopic, and may be stored in a sealed
desiccator with desiccant changed as needed, if required for the application.
4. Suspending Dry Microspheres: Dry silica microspheres may be dispersed in aqueous buffers or solvents (e.g. ethanol, methanol, THF, or DMSO).
An appropriate amount of silica powder should be added to the fluid of interest (dilute suspensions are easier to handle), typically around 1 – 10%),
and rigorously vortexed. The vial or tube containing the silica suspension should then be placed in a sonic bath. (Note: Probe sonicators are typically
ineffective for dispersing powders.) Bath sonicate for ~10 minutes, and confirm that the microspheres are dispersed by viewing a drop of suspension
under a light microscope (400X magnification). Individual microspheres 1µm or larger may be discerned at this magnification, and clumps of smaller
microspheres will be clearly visible. If clumps are visible, continue to bath sonicate for 10 minute cycles until the spheres are fully dispersed. For
continued issues with aggregates/clumps, pre-grinding of the powder with a mortar/pestle may aid in resuspension. Furthermore, a filter of appropriate
pore size can be used to remove undesired aggregates (surfactant may be necessary during the filter process to prevent the formation of a cake over the
pores). It’s also important to remember that pH, salts, or the buffer, could be contributing to clumping as well.
5. Coating Microspheres: To covalently couple biomolecules to silica microspheres, the spheres must first be derivatized. This
typically involves the regeneration of hydroxyl groups through an acid incubation (2N nitric acid at room temperature for 1 hour with rotation) followed
by immediate silanization, or drying and later silanization. Acid-washed or derivatized (silanized) spheres should be stored dry with a desiccant. See the
References section for additional protocols.
Adsorption is a common strategy for the assembly of lipid bilayers and for the isolation of nucleic acids. Silica microspheres may be coated with proteins via
adsorption (see TechNote 204, Adsorption to Microspheres); however, as desorption of protein from the hydrophilic bead surface is expected to occur over
time, covalent coupling is a better coating strategy for applications that require long-term stability. See the Storage and Stability section below.
Scanning Electron Microscope image of (4.14µm) silica microspheres.
1. 聚集：如果观察到聚集，可以使用超声波处理（浴式超声波仪，约 10 分钟；探头超声波仪，约 1 分钟）。另见技术说明
202，微球聚集体。
2. 洗涤：推荐标准洗涤方法，即在可行的情况下进行离心，并对微球进行透析或过滤
<500nm。参见技术说明 203，洗涤微球。请注意羧基 (COOH) 或胺 (NH2
) 表面基团（来自硅烷）将与
悬浮液中的那些。因此，预计每次水洗都会去除一定量的表面基团。
3. 将微球转移到溶剂中并干燥：直径>0.5µm 的二氧化硅微球可以干燥成粉末。脱水
表面（除去吸附的水），微球应首先用有机溶剂清洗，如乙醇或 THF。那么研究人员应该
首先将微球从水性缓冲液转移到溶剂浓度增加的溶液中，然后将它们从溶液中分离出来
（通过沉降、离心或过滤）。然后将微球从潮湿的饼状物中干燥，在露天或在干燥箱中（例如 24 小时
70℃）。可用研钵和研杵将干饼压碎成粉末。干粉极易吸湿，可密封保存
如果应用需要，可根据需要更换带有干燥剂的干燥器。
4. 悬浮干微球：干二氧化硅微球可以分散在水性缓冲液或溶剂（例如乙醇、甲醇、THF 或 DMSO）中。
应将适量的二氧化硅粉末添加到感兴趣的流体中（稀释的悬浮液更易于处理），通常约为 1 – 10%），
并严格涡旋。然后应将装有二氧化硅悬浮液的小瓶或试管放入声波浴中。 （注：探头超声波仪通常是
对分散粉末无效。）浴超声处理约 10 分钟，并通过观察一滴悬浮液确认微球已分散
在光学显微镜下（放大 400 倍）。在此放大倍数下可以看到 1 µm 或更大的单个微球，而更小的团块
微球将清晰可见。如果团块可见，继续超声浴 10 分钟循环，直到球体完全分散。为了
骨料/团块的持续问题，用研钵/研杵预研磨粉末可能有助于重新悬浮。此外，适当的过滤器
孔径可用于去除不需要的聚集体（在过滤过程中可能需要使用表面活性剂以防止在过滤器上形成滤饼）
毛孔）。同样重要的是要记住，pH、盐或缓冲液也可能导致结块。
5. 包被微球：要将生物分子共价偶联到二氧化硅微球上，必须首先对微球进行衍生化。这
通常涉及通过酸孵育（2N 硝酸在室温下旋转 1 小时）再生羟基，然后
通过立即硅烷化，或干燥和随后的硅烷化。酸洗或衍生（硅烷化）的球体应使用干燥剂干燥储存。见
附加协议的参考部分。
吸附是脂质双层组装和核酸分离的常用策略。二氧化硅微球可以通过蛋白质包被
吸附（参见技术说明 204，微球吸附）；然而，由于蛋白质从亲水珠表面的解吸预计会发生
时间，对于需要长期稳定性的应用，共价偶联是一种更好的涂层策略。请参阅下面的存储和稳定性部分。
(4.14µm) 二氧化硅微球的扫描电子显微镜图像。
PDS 702
REFERENCES
1. Cras, J.J., C.A. Rowe-Taitt, D.A. Nivens, F.S. Ligler. 1999. Comparison of cleaning methods of glass in preparation for silanization. Biosens Bioelectron,
14(8-9):683-688.
2. Falipou, S., J.M. Chovelon, C. Martelet, J. Margonari, D. Cathignol. 1999. New use of cyanosilane coupling agent for direct binding of antibodies to
silica supports. Physiochemical characterization of molecularly bioengineered layers. Bioconjugate Chem, 10(3):346-353.
3. Iler, R.K. 1979. The chemistry of silica: solubility, polymerization, colloid and surface properties, and biochemistry. New York: John Wiley & Sons.
4. Kumar, A., O. Larsson, D. Parodi, Z. Liang. 2000. Silanized nucleic acids: a general platform for DNA immobilization. Nucleic Acids Res, 28(14):e71.
5. Steinberg, G., K. Stromsborg, L. Thomas, D. Barker, C. Zhao. 2004. Strategies for covalent attachment of DNA to beads. Biopolymers, 73(5):597-605.
6. Walsh, M.K., X. Wang, B.C. Weimer. 2001. Optimizing the immobilization of single-stranded DNA onto glass beads. J Biochem Biophys Methods,
47(3):221-231.
7. Weetall, H.H. 1993. Preparation of immobilized proteins covalently coupled through silane coupling agents to inorganic supports. Applied Biochem
Biotechnol, 41(3):157-188.
8. Ferguson JA, Steemers FJ, Walt DR. (2000) High-density fiber-optic DNA random microsphere array. Anal Chem; 72(22):5618-5624.
9. Lauer S, Goldstein B, Nolan RL, Nolan JP. (2002) Analysis of cholera toxin-ganglioside interactions by flow cytometry. Biochemistry; 41(6):1742-51.
STORAGE AND STABILITY
As a general note on stability of functionalized silica, the surface is stabilized in aqueous systems by coating proteins or other large molecules that are
likely to have multi-point attachment. Surface groups will be lost if the uncoated NH2
– or COOH-silica beads are stored as an aqueous suspension, or if
small molecules (that have only single point attachment, e.g. peptides, oligos, or small molecule dyes) are coupled and stored in aqueous buffers. These are
typically stored in a solvent, e.g. acetone, ethanol, etc. Acid-washed or functionalized silica may be stored dry at room temperature or in solvent (e.g. EtOH)
to preserve surface groups.
Store suspended (plain and coated) silica particles at 2-8˚C. Freezing may result in irreversible aggregation and loss of binding activity.
Coated silica microspheres should be stored in a buffer or suspending solution that is suitable for both the biomolecule and the silica matrix. Stability of
coated microspheres should be determined empirically.
Dry particles should be stored tightly sealed at room temperature. A desiccator with desiccant may be employed if needed.
This product is for research use only and is not intended for use in humans or for in vitro diagnostic use.
Cat. Code Description
SS02000 Plain Silica 0.15μm
SS02001 Plain Silica 0.30μm
SS02002 Plain Silica 0.40μm
SS03000 Plain Silica 0.50μm
SS03001 Plain Silica 0.70μm
SS03002 Plain Silica 0.90μm
SS04000 Plain Silica 1.0μm
SS04001 Plain Silica 1.50μm
SS04002 Plain Silica 2.0μm
SS05000 Plain Silica 2.50μm
SS05001 Plain Silica 3.0μm
SS05002 Plain Silica 4.0μm
SS05003 Plain Silica 5.0μm
SSD2001 Dry – Plain Silica 0.30μm
SSD3000 Dry – Plain Silica 0.50μm
SSD4000 Dry – Plain Silica 1.0μm
SSD4001 Dry – Plain Silica 1.50μm
SSD5000 Dry – Plain Silica 2.50μm
SSD5001 Dry – Plain Silica 3.0μm
SSD5002 Dry – Plain Silica 4.0μm
SSD5003 Dry – Plain Silica 5.0μm
SC03000 Carboxyl Silica 0.5μm
SC04000 Carboxyl Silica 1.0μm
SC05000 Carboxyl Silica 2.0μm
SC05001 Carboxyl Silica 5.0μm
SA03000 Amine Silica 0.5μm
SA04000 Amine Silica 1.0μm
SA05000 Amine Silica 5.0μm
Standard sizes available are 0.5g, 1.5g, or 5.0g
CS01001 Streptavidin Silica 0.5μm
CS01001 Streptavidin Silica 1.0μm
CS01002 Streptavidin Silica 5.00μm
Standard sizes for Streptavidin Silica are 1mL, 2mL, 5mL, or 10mL