Carboxylate-Modified Polystyrene Latex Beads, >10 µm – Catalog #B202646

Carboxylate-Modified Polystyrene Latex Beads (Catalog #B202646) are large, monodisperse polystyrene microspheres functionalized with surface carboxyl groups. At >10 µm diameter in a 5 mL suspension, they are the largest in the carboxylate-modified polystyrene family, offering maximum ease of handling, visibility, and manual manipulation. The large particle size is ideal for applications where the assay workflow prioritizes convenience and visual inspection over maximum surface area: manual immunoassays, single-well or tube-based tests, magnetic bead separation, and educational demonstrations. Carboxyl groups are readily activated by EDC (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide) for straightforward protein coupling.

Scientific Overview

Carboxylate-modified polystyrene latex beads larger than 10 µm in diameter are used in applications where the bead-to-solution ratio, visibility, and ease of physical manipulation take priority over maximum surface area per unit volume. Even though larger beads have proportionally less surface area (a 15 µm sphere has only one-third the surface-area-to-volume ratio of a 5 µm sphere), a single large bead can still accommodate 100–500 protein molecules, sufficient for many detection and separation workflows.

The primary advantages of large beads include:

• Individual beads are easily visible to the naked eye and under standard light microscopy
• Beads settle rapidly under gravity, simplifying particle recovery without centrifugation
• Easy resuspension with gentle pipetting; no vortexing required
• Compatible with manual one-tube workflows and simple gravity-based separation
• Ideal substrate for magnetic core coating (creating large magnetic beads for high-throughput separators)

Key applications include:

• Manual immunoassays and affinity capture experiments
• Immunoprecipitation and co-IP from cell lysates or tissue homogenates
• Bead-based cell sorting and enrichment
• Educational laboratory experiments and training
• Custom assay development where beads must be easily observed and manipulated by hand

Usage & Handling Guidance

Store at 2–8°C. The large size ensures easy, trouble-free resuspension: simply invert the tube 3–5 times to mix. No vortexing or sonication is necessary. Beads will settle rapidly (within minutes) in aqueous solutions.

• Coupling chemistry: Activate carboxyl groups with EDC (10–40 mM in pH 5–6 coupling buffer) for 15–30 minutes. Add protein (10–100 µg/mL) and incubate 1–4 hours at 20°C or overnight at 4°C with gentle inversion.
• Recovery by gravity: After incubation, allow beads to settle for a few minutes, then carefully remove the supernatant. No centrifugation is needed.
• Washing: Resuspend in wash buffer (PBS + 0.1% Tween-20 or equivalent), allow to settle, and remove supernatant. Repeat 2–3 times as needed.
• Blocking: To minimize non-specific binding, incubate coupled beads with BSA (1–5% in PBS) for 30 minutes, then wash.
• Use in assays: Add to assay wells or tubes; beads settle naturally and are easy to track visually. Centrifugation is optional; gravity settling alone usually suffices.

What You Get

• 5 mL of carboxylate-modified polystyrene latex beads at >10 µm diameter
• Supplied as ready-to-use suspension
• Reactive carboxyl groups suitable for EDC/NHS conjugation
• Large size for maximum ease of handling and visualization
• For research use only (RUO)

Why Researchers Choose It

• Beads are individually visible to the naked eye and easily tracked in assays
• Settle rapidly under gravity, eliminating need for centrifugation in many workflows
• Extremely easy to resuspend; no risk of aggregation or clumping with gentle inversion
• Ideal for manual, low-throughput assays and educational lab exercises
• Proven chemistry: the same reactive carboxyl surface as smaller variants, just at a more convenient size for hands-on work

Frequently Asked Questions (FAQ)

• How much protein loads onto these large beads?
  A 15 µm bead has a surface area of roughly 700 µm² and can typically accommodate 100–500 protein molecules, depending on protein size and coupling efficiency. This is sufficient for most immunoassay and affinity-capture workflows.
• Do I need to centrifuge to recover the beads?
  No. Large beads settle rapidly (within 5–10 minutes) under gravity, so you can simply wait and carefully pipette off the supernatant. Centrifugation is optional and not necessary for most applications.
• Can I use these in flow cytometry?
  Standard flow cytometers are typically optimized for beads in the 1–10 µm range. These very large beads may not pass through narrow nozzles or may clog instruments. For flow cytometry, choose smaller variants (1.0–2.9 µm).
• Are these beads suitable for high-throughput screening?
  These beads are best suited for manual, low-to-moderate-throughput workflows. For automated high-throughput screening, choose smaller beads (1–3 µm) that are compatible with automated plate readers and liquid handlers.
• Can I make magnetic beads from these?
  Yes. Larger beads can be coated with or attached to magnetic particles to create large magnetic beads, which are highly convenient for automated magnetic bead handlers and separators.
• How do the prices compare for different sizes?
  Price variation reflects manufacturing and handling differences. Larger beads are often less costly per particle but provide less total surface area. Request a quote to compare by cost per assay or per square meter of surface area.

References

• Molina-Bolívar JA, Galisteo-González F, Hidalgo-Alvarez R. Particle enhanced immunoassays stabilized by hydration forces: a comparative study between IgG and F(ab)2 immunoreactivity. J Immunol Methods. 1998;211(1-2):87-95.
• Fortin M, Hugo P. Surface antigen detection with non-fluorescent, antibody-coated microbeads: an alternative method compatible with conventional fluorochrome-based labeling. Cytometry. 1999;36(1):27-35.
• Kamyshny A, Feldman A, Baszkin A, Boissonnade MM, Rosilio V V, Magdassi S. Chemically Modified Glucose Oxidase with Enhanced Hydrophobicity: Adsorption at Polystyrene, Silica, and Silica Coated by Lipid Monolayers. J Colloid Interface Sci. 1999;218(1):300-308.