Ordering information
Name	Cat. No.	Vol.	Scheme
G-Ts	PMG011-2	2 ml

1. Overview

PuriMag™ G-Ts, tosyl-activated Magnetic Nanoparticles are uniform, polymer-coated superparamagnetic nanoparticles. Their hydrophilic surface ensures excellent dispersibility, low non-specific adsorption, and easy handling in diverse buffers. The beads feature a high-density surface coating of tosyl-activated groups, enabling covalent immobilization of ligands containing -NH₂ or -SH groups for bioseparation without coupling agents.

During coupling, hydrophobic tosyl groups are eliminated, converting the bead surface to hydrophilic. This chemistry preserves ligand bioactivity while achieving:

        High yield in cell/bacterial lysates

        Low non-specific binding

        Rapid immunoassay solid-phase applications

        Screening of molecular targets or phage display libraries

Ligands with affinity for specific targets (tags, receptors, enzymes) can be surface-coupled to PuriMag™ G-Ts beads.

Features & Advantages:
    Pre-activated for immediate use

    Optimized Coupling: Efficient at pH 7.5–9.5, 37°C
    Charge-neutral surface post-coupling
    Stable covalent bonds with minimal ligand leakage
    Low non-specific binding
    Capacity: 1–20 mg protein or 0.1–2 mg peptide per gram beads
    Applications: Cell sorting, immunoprecipitation, antibody/protein/peptide/DNA/RNA purification

Schematic Diagram of PuriMag™ G-Ts Bead Coupling Mechanism:

2. product description

Product Specifications
Description	Polymer coated Fe3O4 nanoparticles
Particle Size	200 nm
Number of Beads	~1.7×1010 beads/mg
Matrix	Proprietary polymer
Functional group	Tosyl group
Group density	~300 µmole / g of Beads
Magnetization	60~70 EMU/g
Formulation	10mg/mL in 1mM HCl
Stability	pH 3.5~10, 4~80 ℃, most organic solvents
Storage	1 year at 2~8 ℃. Do not freeze.

3. Instructions for Use

Important Notes:

    1.Ligands must be free of competitive agents (e.g., proteins, sugars, stabilizers).

    2.Adding ammonium sulfate (Buffer C) to a final concentration of 1.0–1.5 M enhances antibody coupling efficiency.

    3.Maximum covalent binding occurs after 12–18 h at 37°C. At 20°C, incubation >20 h is required. At 4°C, binding is slow (>48 h); use Buffer A for low-temperature coupling.

A. Required Materials

    1.Buffers A/B/C for bead pre-wash and coupling:

        Buffer A (pH-stable ligands)

        Buffer B (pH-sensitive ligands)

    2.Do not add proteins (except target ligands), sugars, or amines to buffers.

    3.Buffers D/E for washing/storing coupled beads:

        Avoid amine-containing buffers (e.g., glycine, Tris) during pre-wash/coupling.

        If BSA interferes, replace with HSA or Tween 20 to reduce aggregation/non-specific binding.

        For preservation, add <0.1% (w/v) NaN₃ to Buffer E.

       Warning: Sodium azide reacts with copper/lead pipes to form highly explosive metal azides.

    4.Buffers Composition

        Buffer A (0.1 M borate buffer pH 9.5): 6.18 g H₃BO₃ (MW 61.83). Dissolve in 800 mL distilled water.   Adjust pH to9.5 using 5M NaOH and adjust volume to 1 L with distilled water.

        Buffer B (0.1 M Na-phosphate buffer, pH 7.4): 2.62 g NaH₂PO₄ × H₂O (MW 137.99) and 14.42 g Na₂HPO₄ × 2 H₂O (MW177.99). Adjust volume to 1 L with distilled water.

        Buffer C (3 M ammonium sulphate in Buffer A or B): 39.64 g (NH₄)₂SO₄ dissolved in Buffer A or B. Adjust pH with NaOH or HCl. Adjust up to 100 mL with Buffer A or B.

        Buffer D (PBS pH 7.4 with 0.5% (w/v) BSA): Add 0.88 g NaCl (MW 58.4) and 0.5% (w/v) BSA to 80 mL 0.01 M sodium phosphate pH 7.4. Mix thoroughly and adjust volume to 100 mL with 0.01 M sodium-phosphate pH 7.4.

        Buffer E (PBS pH 7.4 with 0.1% (w/v) BSA): Add 0.88 g NaCl (MW 58.4) and 0.1% (w/v) BSA to 80 mL 0.01 M sodium phosphate pH 7.4. Mix thoroughly and adjust volume to 100 mL with 0.01 M sodium-phosphate pH 7.4.

B. Coupling Protocol

B-1. Bead Washing

    1.Resuspend PuriMag™ beads in original vial (vortex >30 s or tilt-rotate 5 min).

    2.Transfer required bead volume to centrifuge tube.

    3.Add equal volume of Buffer A or B (minimum 1 mL). Resuspend.

    4.Place tube on magnetic stand. Discard supernatant.

    5.Remove tube from stand. Resuspend beads in equal volume Buffer A/B (matching initial bead volume).

B-2. Ligand Coupling to Beads
*Scale for >10 mg beads. Standard: 2.5 mg beads (~250 μL), 50 μg ligand/mg beads. Optimal concentration: 2.5 mg/mL.*

    1.Transfer 250 μL washed beads to new tube. Place on magnetic stand. Discard supernatant.

    2.Resuspend beads in 100 μg ligand + Buffer A/B to 150 μL total volume. Mix by vortex/pipetting.

    3.Add 100 μL Buffer C. Mix by pipetting.

    4.Incubate with rotation at 37°C for 12–18 h.

    5.Place tube on magnetic stand. Discard supernatant.

    6.Add 1 mL Buffer D. Incubate at 37°C for 1 h with agitation.

    7.Place on magnetic stand. Discard supernatant.

    8.Add 1 mL Buffer E. Vortex 5–10 sec.

    9.Place on magnetic stand. Discard supernatant.

    10.Repeat Steps 8–9.

    11.Resuspend in Buffer E to desired concentration.

B-3. Target Protein Isolation
Typical binding: 1–20 μg target protein per mg coupled beads (optimize per application).

    1.Add 1–20 μg target protein sample to 100 μL ligand-coupled beads.

    2.Tilt-incubate to capture target.

    3.Place tube on magnetic stand for ≥2 min (longer for viscous samples). Discard supernatant.

    4.Add 1 mL Buffer D or E. Vortex 5–10 sec.

    5.Place on magnetic stand. Discard supernatant.

    6.Repeat Steps 4–5 twice.  

         (For research use only!)