Microplates knowledge base

Start with the basics

• What is a microplate? The plain-language definition, the five choices that define a plate, and how a plate differs from a tube, a dish, and a reader.
• The complete guide to microplates: the six plate families and their applications.
• 96 well plate types: well shapes, colors, and materials.
• 96 well plates compared by workflow, with the volume and use table.

By detection method

• Absorbance and colorimetric assays: clear flat bottom plates; the color logic is on the types page, and ELISA-specific choices in the ELISA plate guide.
• Fluorescence: black plates, solid or clear bottomed; see plate colors on the types page and the cross-talk section below.
• Luminescence: white plates; the cell culture surfaces guide covers white plates for luminescence readouts.
• Imaging and high content screening: black clear-bottom plates and flatness; format trade-offs are in the cell culture formats guide.
• Storage: polypropylene deep well plates; start with the deep well plate guide.

Dimensions and volumes

• 96 well plate dimensions: footprint, pitch, heights, and a dimension drawing.
• 96 well plate volumes: working and total volume per well by type.
• 384 well plate dimensions and the 384 well plate guide, including total volume and well surface area.
• 384 vs 96 well plates: when the smaller format pays.

Materials, surfaces, and coatings

• Materials and autoclaving: polystyrene vs polypropylene, and which plates can be reused.
• ELISA coating and binding surfaces: high vs medium bind, coating volumes, washing.
• Cell culture surfaces: treated vs untreated, coated plates, well shapes.
• Glass coated plates: what the glass layer inside a polypropylene well does for compound storage.

Sealing, storage, and handling

• Sealing deep well plates: films, mats, heat seals, and freezing at -80 °C.
• Storing coated ELISA strips: foil pouch, desiccant, 2 to 8 °C.
• Plate map templates and the plate map maker: laying out samples before pipetting, the cheapest error prevention there is.

Cell culture questions

• Treated vs untreated, and why cells fail to attach.
• Formats and seeding numbers, including 384 well culture and growth areas.
• Surfaces, well shapes, and white culture plates.

Cross-talk: signal leaking between wells

Cross-talk is signal from one well registering in its neighbors. A bright well inflates the readings around it, so the effect grows with signal strength and shows first in high-signal assays such as chemiluminescence. Shorter emission wavelengths carry more energy and tend to cross-talk more.

It comes from two places. The instrument: optics slightly misaligned to the plate, or masking and apertures that let a sliver of a neighboring well into the detector. The plate: light piping laterally through the well walls, the plate bottom, or a clear seal left on for the read. The design factors are wall transparency, wall and bottom thickness, well-to-well distance, and well geometry.

Plate color is the practical lever, and the ranking is stable: clear plates cross-talk the most, white plates sit in the middle (how much varies with the white pigment loading), light grey plates sit below white, and black plates cross-talk the least. Match the color to the readout, black for fluorescence, white accepting some cross-talk as the price of luminescence sensitivity, and test any seal you plan to read through, because a seal that is optically fine for absorbance can pipe light in a luminescence read.

The edge effect: why the perimeter reads differently

The edge effect is the pattern where wells on the plate perimeter return systematically higher or lower values than wells in the center. It appears in biochemical and cell-based assays alike, and it is usually environment, not samples.

The reported causes are consistent. Thermal gradients: edges heat and cool faster than the center, so plates moved in and out of incubators, or read at room temperature after incubation, develop unevenly. Evaporation: edge wells lose liquid faster, concentrating salts and shifting pH and osmolarity; a lid that breathes unevenly makes it worse. The effect grows as wells shrink, so 384 and 1,536 formats suffer more than 96.

What reduces it: seal or lid the plate during incubation; run incubations at high humidity; fill unused perimeter wells with medium or buffer so the working wells are no longer the edge; let a seeded cell plate rest about an hour at room temperature before incubating, a published technique that evens out cell distribution in edge wells; and randomize or rotate sample positions so any residual pattern does not align with your groups. Leaving the perimeter empty works too, but at 384 it throws away a fifth of the plate to avoid a problem the steps above mostly solve.

Related guides

• Arctic White's deep well plate guide
• Arctic White's 384 well plate guide

Common questions