Choosing a 48 well plate without buying the wrong case

Start from the job

Name what happens to the well's contents at the end. If the plate is read in place and discarded, a culture or assay plate serves. If material comes back out, cells harvested, extract recovered, supernatant kept, you need wells sized and shaped for recovery: deep well plates with pyramid or round bottoms that pool the sample where a tip can reach it. If liquid passes through, it is a filter plate, and the membrane choice matters more than the plate. Writing the last step down first eliminates most of the catalog in one pass.

Well shape and bottom

Round wells suit culture and mixing. Square wells pack more volume into the same grid, which is why deep well 48 plates are square or rectangle: the corners buy capacity, and a pyramid bottom funnels the last liquid to the center for recovery, while a round bottom resuspends pellets more gently. Flat bottoms are for growing and reading; anything harvested wants a shaped bottom. Plate color follows the read: clear for imaging and absorbance, white for luminescence, black for fluorescence.

Height, lids, and the fit checks

A 48 well culture plate stands about as tall as any shallow plate and takes a standard lid. Deep well 48 plates stand several times taller, and that height is where purchases fail: shaker clamps, incubator shelves, handler grippers, and stackers all have limits a catalog photo does not show. Check three numbers before ordering a case: overall height, height with the seal or mat on, and the skirt profile your handler grips. If a liquid handler is involved, confirm the plate definition exists in its software, because a 48 deep well that the robot cannot model is a manual plate at a robot price.

Material and sterility

Culture plates are polystyrene, clear and treatable. Deep well and filter plates are polypropylene, for solvent resistance, low binding, and freezer tolerance. Sterility follows the work: culture plates sterile, always; deep well plates pre-sterilized when the contents are alive or going into cells, standard when they hold chemistry or freezer stocks. Do not pay for sterile storage plates you will autoclave or use for solvent work, and do not save money the other way on culture plates.

Surface treatment: the adherent versus suspension choice

Tissue culture treated (TC treated) plates have their polystyrene growth surface plasma treated so it wets properly and carries a charge that cells can attach to; adherent cells spread and grow on it. Non-treated plates keep the natural hydrophobic polystyrene surface, so cells cannot attach and grow in suspension instead. The rule is short: adherent cells need a treated plate, suspension cells need a non-treated one, and trying to grow adherent cells on an untreated plate is the most common reason a 48 well culture never takes off. Coated plates, collagen or poly-lysine over the treated surface, are the step beyond for weakly adherent and primary cells. Treatment is a culture plate question; deep well and filter plates are not surface treated in this sense.

Glass bottom plates, for imaging

Glass bottom 48 well plates swap the polystyrene well floor for a thin sheet of borosilicate glass, usually cover glass thickness at about 0.17 mm, bonded into a polystyrene frame. The point is optical: a molded plastic bottom is too thick and too variable for high numerical aperture objectives, so confocal and high resolution microscopy move to glass. Growth area stays the familiar 0.95 cm2. The trade-offs are price and fragility, and no benefit at all for routine work: if the instrument is a plate reader or a low magnification scope, a standard flat bottom plate does the same job for less.

Sealing a 48 well plate

Culture plates take lids, and the lid is part of the evaporation system, not a dust cover. Deep well plates take cap mats or adhesive seals: a silicone mat for plates that go on and off a shaker or into a freezer repeatedly, an adhesive film for one-way storage, a heat seal for archives. The 48 rectangle format has mats molded to its well pattern; square well plates take mats cut to the 6 by 8 grid. Match the seal to the well shape on the product page, not to the well count alone, and check the sealed height against your stacker before the case arrives.

Related guides

• 24 well plate buying guide
• Deep well plate guide

Common questions