{"product_id":"carboxylate-modified-polystyrene-latex-beads-0-3-um","title":"Carboxylate-Modified Polystyrene Latex Beads (0.3 µm)","description":"\u003cdiv style=\"max-width:1400px; margin:0 auto; padding:40px 20px; font-family:'Open Sans',sans-serif; font-weight:300; background:#fff; color:#333; font-size:0.95rem; box-sizing:border-box;\"\u003e\n  \u003cdiv style=\"display:flex; flex-direction:column; gap:20px;\"\u003e\n\u003ch2 style=\"margin:0; font-weight:600;\"\u003eCarboxylate-Modified Polystyrene Latex Beads (0.3 µm) – Catalog #B202638\u003c\/h2\u003e\n\u003cp\u003eCarboxylate-modified polystyrene latex beads are the workhorse of flow cytometry, fluorescence microscopy, and immunoassay development. Polystyrene is prized for its uniformity, optical clarity, hydrophobic backbone, and inertness. The 0.3 µm size sits at the intersection of optical properties (small enough to minimize light scattering, large enough for easy visualization and handling) and chemical properties (high surface area, fast binding kinetics, suitability for both fluorophore and protein conjugation). The carboxylate surface coating provides reactive anchor points for direct coupling of antibodies, enzymes, fluorophores (via amine-reactive linkers), biotin, streptavidin, and other targeting molecules. This standardized format is compatible with commercial fluorescent labeling kits and enables rapid development of custom diagnostic reagents, assay controls, and research tools.\u003c\/p\u003e\n\u003cdiv style=\"overflow-x:auto; max-width:100%; margin-bottom:20px;\"\u003e\n\u003ctable style=\"width:100%; max-width:640px; border-collapse:collapse;\"\u003e\n\u003ctbody\u003e\n\u003ctr style=\"border-bottom:1px solid #ddd;\"\u003e\n\u003ctd style=\"width:150px; padding:6px 10px 6px 0; vertical-align:top;\"\u003e\u003cstrong\u003eCatalog Number:\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:6px 0;\"\u003eB202638\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"border-bottom:1px solid #ddd;\"\u003e\n\u003ctd style=\"width:150px; padding:6px 10px 6px 0; vertical-align:top;\"\u003e\u003cstrong\u003eAmount:\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:6px 0;\"\u003e5 mL\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"border-bottom:1px solid #ddd;\"\u003e\n\u003ctd style=\"width:150px; padding:6px 10px 6px 0; vertical-align:top;\"\u003e\u003cstrong\u003eParticle Size:\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:6px 0;\"\u003e0.3 µm (300 nm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"border-bottom:1px solid #ddd;\"\u003e\n\u003ctd style=\"width:150px; padding:6px 10px 6px 0; vertical-align:top;\"\u003e\u003cstrong\u003eMaterial:\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:6px 0;\"\u003ePolystyrene latex\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"border-bottom:1px solid #ddd;\"\u003e\n\u003ctd style=\"width:150px; padding:6px 10px 6px 0; vertical-align:top;\"\u003e\u003cstrong\u003eSurface Functionality:\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:6px 0;\"\u003eCarboxylate groups (–COO⁻)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"border-bottom:1px solid #ddd;\"\u003e\n\u003ctd style=\"width:150px; padding:6px 10px 6px 0; vertical-align:top;\"\u003e\u003cstrong\u003eSupplied As:\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:6px 0;\"\u003eAqueous suspension\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"border-bottom:1px solid #ddd;\"\u003e\n\u003ctd style=\"width:150px; padding:6px 10px 6px 0; vertical-align:top;\"\u003e\u003cstrong\u003eApplications:\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:6px 0;\"\u003eProtein labeling, flow cytometry, fluorescence microscopy, immunoassays, surface conjugation\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"border-bottom:1px solid #ddd;\"\u003e\n\u003ctd style=\"width:150px; padding:6px 10px 6px 0; vertical-align:top;\"\u003e\u003cstrong\u003eStorage:\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:6px 0;\"\u003e2–8 °C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"border-bottom:1px solid #ddd;\"\u003e\n\u003ctd style=\"width:150px; padding:6px 10px 6px 0; vertical-align:top;\"\u003e\u003cstrong\u003eKeywords:\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:6px 0;\"\u003ecarboxylate-modified polystyrene, carboxyl polystyrene latex, polystyrene microspheres, polystyrene particles, latex beads\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003ch3 style=\"margin-top:30px;\"\u003eScientific Overview\u003c\/h3\u003e\n\u003cp\u003ePolystyrene is a synthetic, hydrophobic polymer with superior optical properties: low autofluorescence, excellent clarity, and minimal light scattering at visible wavelengths. This combination makes polystyrene the standard material for flow cytometry beads, calibration standards, and assay controls. At 0.3 µm (300 nm) diameter, these beads scatter light enough to be visible in phase-contrast microscopy and detectable by most flow cytometers, yet small enough to diffuse rapidly through aqueous solutions and penetrate narrow spaces in tissues or gels.\u003c\/p\u003e\n\u003cp\u003eThe carboxylate surface coating is created by synthesis or post-conjugation chemistry, providing negatively charged (at physiological pH) anchor points that prevent non-specific protein adsorption (carboxyls are hydrophilic, while the polystyrene core is hydrophobic). This coating enables covalent attachment of targeting molecules via EDC chemistry: carboxyls are activated to O-acylisourea intermediates, which react with primary amines on proteins, antibodies, and ligands to form stable amide bonds. Alternatively, carboxyl groups can be activated by other methods (e.g., sulfur-based linkers, click chemistry) to expand the range of conjugatable molecules.\u003c\/p\u003e\n\u003cp\u003eKey applications include:\u003c\/p\u003e\n\u003cul style=\"padding-left:20px;\"\u003e\n\u003cli\u003eCreating fluorescently labeled probes: couple antibodies, aptamers, or proteins to fluorophore-conjugated beads for detection assays\u003c\/li\u003e\n\u003cli\u003eFlow cytometry controls and calibration: standardized bead populations with defined size and fluorescence are essential for instrument calibration and validation\u003c\/li\u003e\n\u003cli\u003eImmunoassays: conjugate capture antibodies to beads for lateral-flow or suspension-based diagnostic assays\u003c\/li\u003e\n\u003cli\u003eMicroscopy markers: use as reference particles for size calibration, background subtraction, or spatial analysis in image-based assays\u003c\/li\u003e\n\u003cli\u003eProtein engineering and display: couple proteins or peptide libraries to beads for in vitro compartmentalization, directed evolution, or selection\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 style=\"margin-top:30px;\"\u003eUsage \u0026amp; Handling Guidance\u003c\/h3\u003e\n\u003cp\u003eBefore coupling, gently mix the suspension by pipetting (avoid vortexing and sonication, which may cause aggregation). For EDC coupling, dilute beads 1:10 to 1:100 in fresh coupling buffer (25 mM MES, pH 5.5–6.5). Add EDC to 20–50 mM and incubate for 5 minutes. Add your target protein and incubate 30 minutes to 2 hours at room temperature. Wash beads 2–3 times by centrifugation (13,000 × g, 3 minutes) in PBS. Resuspend in storage buffer (PBS with 0.1% BSA and 0.02% sodium azide) for long-term storage at 2–8 °C.\u003c\/p\u003e\n\u003cul style=\"padding-left:20px;\"\u003e\n\u003cli\u003eDo not use high-speed vortexing or sonication; use gentle pipetting to resuspend and mix beads\u003c\/li\u003e\n\u003cli\u003eFor optimal coupling, maintain pH between 5.5 and 6.5 during EDC activation and protein addition\u003c\/li\u003e\n\u003cli\u003eCentrifuge-based washing is preferred over magnetic separation (these beads are not magnetic)\u003c\/li\u003e\n\u003cli\u003eBlock coupled beads with 5–10% BSA, casein, or serum for 30 minutes to an hour before use to minimize non-specific binding\u003c\/li\u003e\n\u003cli\u003eStore in PBS with carrier protein (BSA) and a preservative (sodium azide, 0.02%) to prevent microbial growth and minimize aggregation\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 style=\"margin-top:30px;\"\u003eWhat You Get\u003c\/h3\u003e\n\u003cul style=\"padding-left:20px;\"\u003e\n\u003cli\u003e5 mL of carboxylate-modified polystyrene latex bead suspension (0.3 µm)\u003c\/li\u003e\n\u003cli\u003eBeads supplied in a stabilizing buffer optimized for long-term storage and minimal aggregation\u003c\/li\u003e\n\u003cli\u003eBeads ready to couple with proteins, antibodies, or fluorophores via EDC chemistry\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 style=\"margin-top:30px;\"\u003eWhy Researchers Choose It\u003c\/h3\u003e\n\u003cul style=\"padding-left:20px;\"\u003e\n\u003cli\u003e0.3 µm size offers optimal balance between optical properties (low scattering, high clarity) and practical handling (visible in microscopy, fast diffusion)\u003c\/li\u003e\n\u003cli\u003ePolystyrene matrix is optically transparent, enabling integration with fluorescent probes and fluorescence-based assays\u003c\/li\u003e\n\u003cli\u003eCarboxylate surface enables rapid, high-efficiency protein coupling via standard EDC chemistry\u003c\/li\u003e\n\u003cli\u003eUniform size and optical properties enable use as internal standards, calibration controls, and validation reagents in flow cytometry\u003c\/li\u003e\n\u003cli\u003eInert, non-magnetic polymer is compatible with a broad range of solvents, pH values, and coupling chemistries\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 style=\"margin-top:30px;\"\u003eFrequently Asked Questions (FAQ)\u003c\/h3\u003e\n\u003cul style=\"padding-left:20px;\"\u003e\n\u003cli\u003e\n\u003cstrong\u003eWhat is the maximum protein loading per bead?\u003c\/strong\u003e\u003cbr\u003eAt 0.3 µm diameter (~0.3 µm³ volume), a single bead offers roughly 0.3 µm² of surface area. Carboxylate density is typically 100–1000 groups per µm², and coupling efficiency is 60–95%. Typical loading is 10⁵–10⁶ protein molecules per bead, or roughly 0.1–1 pg of protein per bead (depending on protein size and coupling conditions).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCan I use these beads in flow cytometry?\u003c\/strong\u003e\u003cbr\u003eYes. These beads are ideal for flow cytometry. They are detectable on most modern cytometers (FSC ~10–50 V, depending on instrument and laser power). Use as positive controls, background subtraction standards, or as conjugate templates for custom assay development.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHow do I couple fluorophores to these beads?\u003c\/strong\u003e\u003cbr\u003eDirectly: activate carboxyls with EDC\/sulfo-NHS and react with amine-labeled dyes (e.g., Alexa Fluor amines, FITC-conjugates). Indirectly: couple streptavidin to beads, then use biotin-labeled dyes. Consult your fluorophore supplier for recommended labeling protocols.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWhat is the refractive index and optical properties?\u003c\/strong\u003e\u003cbr\u003ePolystyrene has a refractive index of ~1.59, similar to some oils and mineral media. Beads are optically transparent (colorless) and show minimal autofluorescence in common fluorescence channels (FITC, TRITC, Alexa Fluor dyes). Scattering is minimal at 0.3 µm, making these suitable for sensitive fluorescence assays.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCan I use these in organic solvents?\u003c\/strong\u003e\u003cbr\u003ePolystyrene is compatible with many organic solvents (ethanol, methanol, acetone, toluene up to 50–75% v\/v). For extended exposure to strong organic solvents or high temperatures, polystyrene may swell or dissolve. Test compatibility with your specific solvent and conditions before large-scale use.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWhat is the difference between these 0.3 µm beads and smaller nanoparticles (e.g., 100 nm)?\u003c\/strong\u003e\u003cbr\u003e0.3 µm beads are easier to visualize in light microscopy and more easily handled (faster sedimentation, less tendency to aggregate). Smaller nanoparticles (100 nm or less) offer faster kinetics and higher surface-area-to-volume ratios but are more challenging to visualize without electron microscopy or advanced optical techniques.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cdiv style=\"margin-top:20px; font-weight:bold; color:#c8102e;\"\u003eThis product is for Research Use Only (RUO). It is not intended for diagnostic or therapeutic use in humans or animals.\u003c\/div\u003e\n\u003chr\u003e\n\u003ch4\u003eReferences\u003c\/h4\u003e\n\u003cul style=\"padding-left:0; margin:0; list-style:none;\"\u003e\n\u003cli style=\"display:flex; justify-content:space-between; align-items:flex-start; gap:12px; padding:8px 0; border-bottom:1px solid #eee;\"\u003e\n\u003cspan style=\"flex:1;\"\u003e\u003c\/span\u003e\u003ca href=\"https:\/\/doi.org\/10.2116\/analsci.20SCP04\" target=\"_blank\" rel=\"noopener\" style=\"flex-shrink:0; margin-top:2px;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/Reference.png?v=1775409336\" alt=\"Reference\" style=\"height:28px; width:auto;\"\u003e\u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli style=\"display:flex; justify-content:space-between; align-items:flex-start; gap:12px; padding:8px 0; border-bottom:1px solid #eee;\"\u003e\n\u003cspan style=\"flex:1;\"\u003e\u003c\/span\u003e\u003ca href=\"https:\/\/doi.org\/10.1016\/j.watres.2016.01.026\" target=\"_blank\" rel=\"noopener\" style=\"flex-shrink:0; margin-top:2px;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/Reference.png?v=1775409336\" alt=\"Reference\" style=\"height:28px; width:auto;\"\u003e\u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli style=\"display:flex; justify-content:space-between; align-items:flex-start; gap:12px; padding:8px 0; border-bottom:1px solid #eee;\"\u003e\n\u003cspan style=\"flex:1;\"\u003e\u003c\/span\u003e\u003ca href=\"https:\/\/doi.org\/10.1039\/c7cs00230k\" target=\"_blank\" rel=\"noopener\" style=\"flex-shrink:0; margin-top:2px;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/Reference.png?v=1775409336\" alt=\"Reference\" style=\"height:28px; width:auto;\"\u003e\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n  \u003c\/div\u003e\n\u003c\/div\u003e","brand":"Molecular Depot","offers":[{"title":"Default Title","offer_id":52809022996778,"sku":"BTS-B202638","price":705.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/B202638.png?v=1790859807","url":"https:\/\/bluetigerscientific.com\/products\/carboxylate-modified-polystyrene-latex-beads-0-3-um","provider":"Blue Tiger Scientific","version":"1.0","type":"link"}