微孔板培養(yǎng)流體力學(xué)分析系統(tǒng)

背景：
軌道搖動(dòng)的微孔板孔內(nèi)培養(yǎng)物的流體動(dòng)力學(xué)取決于：

•孔的形狀：方形孔比圓形孔產(chǎn)生更高的湍流。

這種效果與錐形燒瓶?jī)?nèi)的擋板效果相當(dāng)，但比后者要溫和。方形引起的額外湍流對(duì)于96孔板是溫和的，而對(duì)于24孔板則更強(qiáng)，尤其是在較高的振蕩頻率下。
•孔的直徑
•培養(yǎng)量
•振動(dòng)頻率
•軌道振動(dòng)器運(yùn)動(dòng)產(chǎn)生的G力。
G力與振動(dòng)幅度成正比，與振動(dòng)頻率的平方成正比：G力= 5.6 x 10-7 x振動(dòng)幅度x rpm2（以mm表示振動(dòng)幅度）。 G力依次決定：

培養(yǎng)液與水平面的夾角。根據(jù)經(jīng)驗(yàn)（對(duì)于*混合而言），對(duì)于24孔板，該角度應(yīng)約為50度（對(duì)應(yīng)于1.2的G力，可以通過(guò)以50 mm / 225 rpm的搖動(dòng)來(lái)建立） ，或25mm / 300rpm）和96個(gè)深孔板的70度（對(duì)應(yīng)于2.5的G力，可以通過(guò)以50 mm / 300rpm搖動(dòng)來(lái)建立）。

在實(shí)踐中：
從搖動(dòng)頻率和搖動(dòng)振幅（以及培養(yǎng)液與水平面的角度）獲知G力，就可以預(yù)測(cè)培養(yǎng)物*混合的程度（直至孔的底部）一定的培養(yǎng)量但是，其他因素也可能會(huì)產(chǎn)生影響，zui明顯的是表面張力（特別是與直徑小于8 mm的孔有關(guān)，例如96圓孔板中的孔），以及培養(yǎng)液能夠達(dá)到的程度。*跟隨振動(dòng)器的運(yùn)動(dòng)（尤其與24孔板中的方形孔相關(guān)，振幅較小且高頻振動(dòng)）。

因此，我們還使用高速攝影機(jī)制作了用于各種微孔板的搖動(dòng)井的視頻，這些微孔板具有不同的培養(yǎng)量以及搖動(dòng)幅度和搖動(dòng)頻率的組合范圍。這些視頻可讓您自己判斷特定的振動(dòng)條件是否適合您的應(yīng)用。

In practice: Knowing the G-force from the shaking frequency and the shaking amplitude, (and so the angle of the culture fluid with the horizontal plane) makes it possible to predict to what extent the culture is fully mixed (down to the bottom of the well) for a certain culture volume. However, also other factors may have an impact, most notably the surface tension (especially relevant for wells with a diameter below 8 mm, such as the wells in 96-roundwell plate), and the degree to what extent the culture fluid is capable of fully following the movement of the shaker (especially relevant for square wells in 24 well plate, shaking at smal amplitude, and a high frequency).Therefore we have also made videos of shaking wells using a high-speed camera for a range of types of microplates, with different culture volumes and a range of combinations of shaking amplitudes and shaking frequencies. These videos allow you to judge for yourself if a specific shaking condition is suitable for your application:

•Videos 6-square deepwell plates

•Videos 24-square deepwell plates

•Videos 24-square extra tall deepwell plates (Hitplate 24)

•Videos 24-round shallow well plates

•Videos 96-square deepwell plates

•Videos 96-square half deepwell plates

•Videos 96-round shallow well plates

Furthermore, we have compiled lists of oxygen-transfer rates from literature data. When comparing these measure maximal oxygen-transfer rates with the videos of shaking wells under the same shaking conditions, the following pattern becomes apparent:

•If the cultures are not mixed down to the bottom of the wells, the OTR is below 30 mmol O2 l^-1 h^-1

•If the cultures are mixed down-to-the-bottom (just, but no further), the OTR is in the range of 30-40 mmol O2 l^-1 h^-1

Oxygen transfer rates, headspace gas exchange rates, and evaporation rates as a result of various orbital shaking conditions and working volumes for 4 different types of microtiter plates in combination with our sandwich covers.

a) Duetz et al. (2004) Biochemical Engineering Journal 17: 181-185 (data determined enzymatically using glucose oxidase, horse radish peroxidase, and ABTS)b) OTR's extrapolated from reference a)c) OTR extrapolated from other data for round vessels (in which surface tension does not play a role).d) Duetz et al. (2000) Appl Environ Microb 66:2641-2646. (data derived from growth curve Pseudomonas putida)e) OTR determined at the Enzyscreen lab from growth curves Pseudomonas putida: procedure as detailed in Duetz et al., Appl Environ Microb 66:2641-2646.f) OTR extrapolated from data from e), applying a conversion factor of 0.5 (two-fold lower oxygen transfer rates at a shaking amplitude of 25 mm instead of 50 mm)g) using the standard sandwich covers supplied. VVM = culture volume per minute