MAGNETIC BEADS: INTRODUCTION 

A Better Design…for Better Performance

PARTICLES

Solution Kinetics

• Rapid contact with target materials; mixers unnecessary

Small Size

• Gentle separation, no cell damage, no shearing of nucleic acids
• No particle shedding during wash steps

Compatible with Flow Cytometry, PCR, & F.I.S.H.

• Particles can be filter-sterilized
• Fewer procedural steps
• No washing out of Excess Antibody or Azides

Non-porous

• Won’t entrap matrix components
• Rapid wash steps
• Broad Product Offering
• Broadest product line of any manufacturer of magnetic particles

Cell Capture / Filter Sterilizable

• 2-5 x 108 cells/ml

MAGNETIC SEPARATORS  & ACCESSORIES

Multiple Static Separations

• Three standard models; custom separators available
• Isolate 108 to 109 cells for under $500

Flow Separations

• Unlimited sample volume from ml to liters

Flow Cells

• Reusable, Sterilizable for rare cells in large volumes, 4 ml to 20 ml
• Flow rates at 5 ml/minute

No Columns, Steel Wool, or Pins

• Won’t irreversibly bind magnetic particles on columns
• No column equilibration
• No metal contamination

TECHNOLOGY

Our Magnetic Particles are available in four nominal sizes; 50nm, 250nm, and special order 150nm and 35nm particles for intracellular applications.  Particle sizes less than one micron were developed to meet customer demand for:

Solution Kinetics

Large magnetic particles, which sink at a faster rate then small particles, require constant agitation or mixing to ensure contact with targeted material.  Too strong an agitation results in cell damage, or shearing of nucleic acids.  Our Magnetics’ small particles diffuse throughout the sample solution, increasing target capture rate.  This phenomenon also eliminates the need for constant agitation.  In addition, our small particles can be filter sterilized.

Size

Magnetic particles, when placed in a magnetic field, form chains and then migrate to the magnetic pole. The larger the particle, the greater the velocity into the wall of the capture vessel. While many magnetic particle companies emphasize speed of separation, speed could be a disadvantage for cellular separation. Viability, cellular damage, entrapment of non- targeted materials, shearing of nucleic acids, and clumping of magnetic particles occur with rapid separations by large particles in a strong magnetic field.  Large magnetic particles >1 micron also interfere with Flow Cytometry & F.I.S.H.  They must be removed prior to Flow Cytometry. 

Our Magnetic particles do not interfere with Flow Cytometry and removal is not necessary.  The particles do not fluoresce, denature, nor damage cells that are enriched for five-color F.I.S.H. analysis of Chromosomes 21, 18, 13, X, and Y.

Because our particles are small and have large surface areas, washing out excess antibody is not required.  The small particles absorb the excess antibody.  Competitive small magnetic particles <100nm lack a sufficient magnetic force of attraction to isolate targeted materials unassisted.  They require ferromagnetic materials in direct contact with sample solutions (i.e., steel wool, wires, columns, etc.).    These magnetic particles adhere to the columns or wires and not all are removed.  The use of columns also requires volumes >250 µl. 

Our Magnetics can perform magnetic isolations with a few µl of volume.  The 50nm Separator can operate without wires or columns.   Furthermore, specially designed reusable flow cells or stationary test tubes allow the separation to occur on the wall of the container.  In negative depletions the unwanted materials are captured on the walls of the flow cell, while the enriched material is captured in the effluent.  In positive isolations the targeted materials are easily removed and concentrated from the walls of the flow cells.  All of this is accomplished in a closed system.

In a cooperating laboratory, our Magnetics outperformed column-based magnetic system in terms of price and performance.  95% of the desired B-cells were positively isolated by our Magnetics, while the column system isolated 70%.  Purity levels for our Magnetics were >90%, while the column purity levels were <.90%.   In comparing costs, our Magnetics was 50% less than the column magnetic system.

Physical Characteristics and Packaging

The 250nm particles have a density of 1.0016 g/cc, surface area of > 4.8 m2/g, and > 10 13 particles/g.  The particle’s magnetic core is composed of magnetite.  They are supplied at a concentration of either 0.5 mg Fe/ml or 1.0 mg Fe/ml. The particles with attached ligands [e.g., Mab,] are suspended in 10mM Phosphate pH 7.5, 0.1% Sodium Azide and 1 mg/ml of BSA. Activated particles, silica particles are suspended in 10mM Phosphate pH 8.5 and 5% IPA. 

The 50nm particles have a density of 1.0004 g/cc, surface area of > 24m2 /g, > 1015. The 50nm particles are packaged in the same concentration as the 250nm particles with the same suspensions. All the magnetic particles are for Research use onlyparticles/g.  The particle’s magnetic core is composed of magnetite. 

OUR MAGNETICS PRODUCTS & SERVICES

• Custom Attachment of any Ligand
• Primary & Secondary Antibodies
• Common Capture Magnetic Particles to Isolate or Enrich Cells, Proteins and Nucleic Acids
• Labeled Chemokines & Fusion Proteins
• Microbiology and Molecular Biology Products
• Magnetic Separators for Static or Flowing Separations.
• Labeled Magnetic Particles e.g., FITC, GFP, anti GFP, anti BrdU
• Custom DNA, RNA, & Peptide Sequences
• Protein Isolation Particles , Magnetic Chromatography Particles
• Custom Primary Antibodies and Services

Because of the diversity of antibody use in the Research Market, Our Magnetics will attach any commercially or privately owned ligand to our particles.

CUSTOM MOLECULAR BIOLOGY PRODUCTS

• Custom Biotinylated Sequences
• Peptides, RNA, DNA with Streptavidin Magnetic Particles
• Labeled Sequences: Peptides, RNA, DNA with FITC
• PE Labeled Magnetic Particles
• Oligo dT Magnetic Particles
• Silica Magnetic Particles

PROTEIN ISOLATION PARTICLES

Our Magnetics offers a broad range of magnetic particles:

• Fusion Protein Tags
• Ion Exchange Functionality (DEAE)
• Reverse Phase (C18)
• Activated Particles (Amine, Carboxyl)
• Streptavidin (see Figure 2.)
• Carboxyl MethylCustom Attachment of Ligands

Streptavidin Magnetic Particles

In a Diagnostic application for Prostate Specific Antigen (PSA), using our Streptavidin 250nm Protein coated Particle the following results were achieved:

• Conditions: 100 µl of sample and 12 µg of magnetic particles, 15-minute incubation [sample + antibody], three 3-minute washes, 1-minute substrate incubation, 1-second measurements.

MAGNETIC SEPARATORS

The Dynamic Separator for the 250nm particle is designed for either slow, gentle isolations or rapid magnetic collection.  Our Magnetics has feature that rapid magnetic separations of large magnetic particles using rare earth magnets can cause shearing of Nucleic acids, cellular damage or viability problems.  The Dynamic Separator allows you to select the rate of magnetic particle collection.  The Magnetic Particles are compatible with competitive rare earth magnetic separators.  The Dynamic Separator accommodates multiple tubes in various sizes, from µl to liter volumes, as well as the Flow Cells, thereby eliminating the need to purchase multiple separators.

The msp Magnetic Separator is an inexpensive rare earth separator that has three permanent magnets fixed in polycarbonate. Both sides of the separator are functional, allowing six 1.5ml tubes or two 15 ml tubes to be attached to the separator. This separator is portable and can be heat-sterilized.

The 50nm Separator ds-3 is made of stronger, neodymium rare earth magnets. The design of the separator allows one to insert a rectangular flow cell or stationary tube within a slot to perform the separation.  This high intensity magnetic field is required for 35nm and 50nm sized magnetic particles.

The Dynamic Separator houses 15 permanent magnets in polycarbonate, which can be heat-sterilized.  It can hold thirty 1.5 ml tubes, ten 15 ml tubes, and four 50 ml tubes.  The vertical magnetic wall can be used for 96 well isolations. The msp is shown in front, on the right.

Flow Cells

Rectangular flow cells with volumes from 4 ml to 20 ml are available for use in closed systems.  These flow cells can be heat sterilized and reused. 

Magnetic Beads - CD Markers

Magnetic Beads - Cell Isolation

Magnetic Beads - Infectious Markers

Magnetic Beads - Human Proteins

Magnetic Beads - Carcinogens

Magnetic Beads - Plant Viruses