0.32 mL Microplates, Round Bottom, PS, Black, BD® Compatible — 290-8196-Z1R | 9/Box | Caplugs® Evergreen

96-Well Round Bottom Microplates, 0.32 mL Well Volume, PS, Black — 290-8196-Z1R | 9/Box (90/Case)

Technical Narrative

The Caplugs® Evergreen is a 96-well round-bottom black Polystyrene (PS) microplate in SBS/ANSI standard footprint — the low-background fluorescence format for fluorescence intensity, FRET, HTRF, and TR-FRET assays where signal-to-noise ratio is the critical analytical parameter. Black PS well walls absorb stray and scattered photons that would otherwise create background signal and well-to-well cross-talk in high-sensitivity fluorescence reads — providing 5–20× lower fluorescence background versus white or natural PS plates for assays where the analyte signal is weak relative to the plate material autofluorescence. The round (U-bottom) geometry allows suspension cells and fluorescent beads to settle uniformly by gravity — enabling efficient suspension cell fluorescence reads with minimal spatial variability from non-uniform cell distribution.

The choice between black and white plates is determined by the detection mode. White plates maximize luminescence signal by reflecting photons toward the detector — the correct choice for luciferase reporter assays and ATP bioluminescence. Black plates minimize background by absorbing all stray light — the correct choice for fluorescence intensity, FRET, HTRF, and TR-FRET where donor bleed-through, acceptor cross-excitation, and plate material autofluorescence are the noise sources that limit assay sensitivity. Natural PS plates are the choice for absorbance-based ELISA and UV-mode assays where plate color does not affect the measurement mode.

At $145.44 per Box of 9 — $1.6160 per plate — the delivers black PS round-bottom fluorescence assay format at bulk economics for programs running 10–100+ fluorescence plates per week. Also available: 290-8195-Z1F (96-well flat-bottom PS Black, 0.37 mL, 9/Box (90/Case)).

Technical Specifications — Caplugs® Evergreen

Fluorescence Assay Compatibility — Round Bottom, Black PS

Black PS plates minimize fluorescence background and well cross-talk — the standard for fluorescence-based assays where signal-to-noise ratio is the primary analytical constraint. Round bottom for suspension cell fluorescence assays where cells must settle uniformly:

Black plates minimize background — use white plates when luminescence signal enhancement is needed alongside suspension culture. For HAI agglutination assays requiring visual scoring, natural PS round-bottom (290-8117-01R) is preferred.

Chemical Resistance — Polystyrene (PS)

Black PS resists aqueous fluorescence assay reagents. Not autoclave-compatible.

Laboratory Applications

The serves cell biology programs running fluorescence assays in suspension cells (GFP/RFP in Jurkat, lymphocytes, PBMC); FRET-based suspension cell assays; cytokine bead array and multiplex bead programs with FI detection; HAI/agglutination assays combined with fluorescent antibody detection; live/dead fluorescence viability in suspension; and any assay requiring low-background fluorescence reads with suspension cell pelleting behavior.

U.S. Manufacturing, Quality & Institutional Procurement

Every Caplugs® Evergreen lot is precision-molded at our California manufacturing facility and subject to rigorous dimensional inspection and material purity verification. We supply reference laboratories, hospital systems, biotech firms, and federal procurement offices under institutional pricing programs with blanket-order support and same-day shipping on stocked inventory. Request a sample below to validate before committing to volume.

Frequently Asked Questions — Caplugs® Evergreen

When should I use black round-bottom versus black flat-bottom plates for fluorescence?

Both provide low-background fluorescence. The difference is the well geometry. Black flat-bottom (290-8195-Z1F) is for adherent cells and assays requiring consistent path length for quantitative plate-reader FI reads. Black round-bottom is for suspension cells and beads that need to settle uniformly by gravity — providing consistent cell distribution for suspension cell fluorescence, bead-based multiplexing, and agglutination assays combined with fluorescent detection. Choose based on whether your cell or particle is adherent (flat) or suspension (round).

Is the black round-bottom plate suitable for cytokine bead array (CBA) assays?

Yes. Black round-bottom plates are well-suited for cytokine bead array (CBA, LEGENDplex, BD CBA) and Luminex-style multiplex bead assays. The round bottom pellets fluorescent beads uniformly during centrifugation and allows efficient supernatant removal, while the black walls minimize background fluorescence during the fluorescence intensity read. Confirm compatibility with your specific CBA workflow — some protocols specify flat-bottom for non-centrifugation bead read formats.

Is the compatible with standard fluorescence plate readers?

Yes. The SBS/ANSI standard footprint ensures compatibility with all standard plate readers in fluorescence intensity mode. For suspension cell fluorescence with round-bottom plates, top-read mode is standard — the reader measures fluorescence from above the settled cell layer. Bottom-read fluorescence is also supported but path length variability from round-bottom geometry should be considered for quantitative assays.