Sandwich covers and clamps for deepwell plates
Square deepwell microtiter plates combine an optimal volume/area ratio with a high degree of mixing and oxygen transfer rates due to the 'baffle effect' caused by the square shapes of the wells (for details, see
hydrodynamics, oxygen transfer rates). The high degree of turbulence mimics the conditions microbial cells encounter in stirred-tank bioreactors.
Deepwell plate sandwich covers prevent cross contamination and excessive evaporation during orbital shaking : i) a soft silicone layer avoids spilling of cells from well to well. The silicone plate is pierced with small holes (at the center of each well) which allows an exchange of headspace air with the surroundings ii) a microfiber filter (blue) and an expanded PTFE filter (green) prevent air-born contaminants to enter the wells. iii) a stainless steel lid with 24 or 96 holes ensures the necessary rigidity (see also
"sandwich covers").
Sandwich covers for 24-square deepwell plates (various types, see
list 24 well covers) allow a culture volume of 2.5-4 ml, and are often used for (pellet-forming) streptomycetes and filamentous fungi, e.g. for growth medium optimization studies or product discovery. Oxygen transfer rates of 40-50 mmol O
2/L/h or more can be readily attained at 220-300 rpm, at shaking amplitudes of 25 and 50 mm (see
hydrodynamics, oxygen transfer rates,
www.videosduetz.com).
For an optimal functioning of the sandwich cover, it is important that the top-side of the microtiter plate is fully flat. Therefore we also supply (re-usable) flattened and polished polypropylene 24-square deepwell microtiter plates. Potentially toxic contaminants have been extracted from the plastic by boiling them in 100 mM sodium hydroxide, and heating them in 100 mM hydrochloric acid for four hours each. See Duetz et al. (2000) should further information be required on the detoxifying process. (CR1424).
Also (since March 2011), a polystyrene disposable (gamma-irradiated) version of this MTP is available (CR1424b)
We supply flattened and detoxified 96-square deepwell microtiter plates (CR1496), These plates (produced by HJ-Bioanalytik) are very strong, re-usable, and potentially toxic contaminants have also been extracted (by Enzyscreen) from the plastic as described above. Alternatively, we supply flattened square deepwell MTPs from Greiner (CR1496b). These plates from Greiner are made from relatively clean polypropylene, and (for most strains) do not need to be detoxified (but do need to be flattened). The polypropylene used for the Greiner MTPs - however - is more brittle, and breaks more easily than the MTPs produced by HJ-Bioanalytik.
The cover clamps for 4 deepwell plates (CR1700) assure that the deepwell plates and its sandwich covers are clamped together tightly; the individual wells are hermetically closed. The cover clamp can be mounted onto orbital shaking platforms from a range of suppliers (generally 4 clamps per shaker, so 16 plates, see photo below), and can be used at g-forces up to 3.
Up to four clamps (16 deepwell MTPs) can be mounted onto a standard shaking platform of 40 x 80 cm: the distance between the rows is required to slide in and out the MTPs + sandwich covers
