Amine-modified Polystyrene Latex Beads (1.0–1.9 µm) – Catalog #B2025493

Amine-modified Polystyrene Latex Beads (Catalog #B2025493) are monodisperse, spherical particles (1.0–1.9 µm diameter) with primary amine groups grafted to the polystyrene surface. Supplied as 1 mL solution, these larger microspheres provide a platform for high-capacity protein immobilization, whole-cell labeling, and immunoassays where large bead size is advantageous for optical detection and manipulation.

Scientific Overview

Polystyrene microspheres in the 1–2 µm size range represent the largest diameter suitable for suspension-phase immunoassays, while remaining in the domain where individual beads can be observed and manipulated under standard light microscopy. At this size, each bead provides an exceptionally large surface area for ligand immobilization: a 1.5 µm microsphere has approximately 10–50 times the surface area of a 100 nm nanoparticle of the same material. This is advantageous when high protein loading capacity is required or when optical visualization of individual bead-ligand conjugates is desirable.

Amine surface chemistry is stable and reactive, enabling straightforward coupling to proteins, antibodies, nucleic acids, and small-molecule ligands via standard carbodiimide (EDC/NHS), reductive amination, or succinimide ester chemistry. The large particle size also makes these beads amenable to microfluidic platforms, flow sorting, and automated liquid handling systems.

Key applications include:

• High-capacity protein and antibody immobilization platforms
• Bead-based enzyme assays with high substrate capacity
• Cell labeling and tracking (with fluorescent or magnetic derivatives)
• Immunomagnetic cell separation (when incorporated with magnetic materials)
• Optical detection and manipulation platforms (microarray, microfluidics)
• Agglutination assays where large bead size enhances optical readout

Usage & Handling Guidance

Store at 2–8°C in the supplied buffer. Vortex gently or invert to resuspend beads that may have settled. Do not sonicate, as aggressive sonication can break or aggregate these larger microspheres.

• Protein coupling: Wash beads 2–3 times in PBS or TBS to remove storage buffer. Incubate with protein and EDC/NHS at a molar ratio of 1:4 to 1:10 (EDC:protein), depending on the desired loading. Incubate for 2–4 hours at room temperature or overnight at 4°C with gentle mixing to prevent bead settling.
• High-capacity loading: The large surface area allows protein loading from 100 to 1000+ µg per mL of bead suspension, depending on the protein size and coupling efficiency. Optimize by performing a titration with your target protein.
• Blocking: After coupling, block free amine groups with glycine (1 M, pH 8) or ethanolamine (1 M, pH 8) for 20–30 minutes at room temperature.
• Suspension stability: These beads settle relatively quickly in water or low-salt buffers. Resuspend by gentle vortexing before each use, and minimize settling time during assays by maintaining gentle agitation.

What You Get

• 1 mL of amine-modified polystyrene latex beads (1.0–1.9 µm), supplied as solution
• Monodisperse microspheres with uniform, reactive amine surface
• Maximum surface area for high-capacity protein immobilization
• Visible under standard light microscopy for individual bead tracking
• Ready-to-use solution—no preparation or activation required
• For research use only (RUO)

Why Researchers Choose It

• Maximum surface area (1.0–1.9 µm size) for high protein loading capacity
• Individual beads visible under light microscopy for direct optical detection
• Amine surface enables rapid, efficient covalent protein immobilization
• Biologically inert polystyrene minimizes nonspecific interactions
• Compatible with manual and automated assay platforms, microfluidics, and optical imaging
• Decades of literature demonstrating stable, high-capacity bioconjugates

Frequently Asked Questions (FAQ)

• What is the protein loading capacity?
  Depends on protein size and coupling efficiency. Typical loading ranges from 100 to 1000+ µg protein per mL of bead suspension. Request a COA/TDS or perform a titration with your target protein.
• Can I see these beads under a microscope?
  Yes. At 1.0–1.9 µm, individual beads are easily visible under a standard light microscope at 40× magnification or higher.
• How long does protein coupling take?
  Typically 2–4 hours at room temperature or overnight at 4°C with EDC/NHS. Optimize by testing different incubation times and bead concentrations.
• Why do my beads settle?
  At this larger size, beads settle faster in low-salt buffers. Resuspend by gentle vortexing before each use and maintain gentle agitation during long incubations.
• Can I use these beads in a magnetic separation system?
  Not directly—these beads are not magnetic. However, if you couple them to magnetic particles or coat them with a magnetic layer, they can be used in magnetic separation workflows.

References

• Xianyu Y, Dong Y, Wang Z, Xu Z, Huang R, Chen Y. Broad-Range Magnetic Relaxation Switching Bioassays Using Click Chemistry-Mediated Assembly of Polystyrene Beads and Magnetic Nanoparticles. ACS Sens. 2019;4(7):1942-1949.
• Yao Q, Gao Y, Gao T, Zhang Y, Harnoode C, Dong A, Liu Y, Xiao L. Surface arming magnetic nanoparticles with amine N-halamines as recyclable antibacterial agents: Construction and evaluation. Colloids Surf B Biointerfaces. 2016;144:319-326.
• Sheng Y, Liao LD, Thakor NV, Tan MC. Nanoparticles for molecular imaging. J Biomed Nanotechnol. 2014;10(10):2641-76.