微孔板培养流体力学分析系统

微孔板培养流体力学分析系统

背景：
轨道摇动的微孔板孔内培养物的流体动力学取决于：

•孔的形状：方形孔比圆形孔产生更高的湍流。

这种效果与锥形烧瓶内的挡板效果相当，但比后者要温和。方形引起的额外湍流对于96孔板是温和的，而对于24孔板则更强，尤其是在较高的振荡频率下。
•孔的直径
•培养量
•振动频率
•轨道振动器运动产生的G力。
G力与振动幅度成正比，与振动频率的平方成正比：G力= 5.6 x 10-7 x振动幅度x rpm2（以mm表示振动幅度）。 G力依次决定：

培养液与水平面的夹角。根据经验（对于*混合而言），对于24孔板，该角度应约为50度（对应于1.2的G力，可以通过以50 mm / 225 rpm的摇动来建立） ，或25mm / 300rpm）和96个深孔板的70度（对应于2.5的G力，可以通过以50 mm / 300rpm摇动来建立）。

在实践中：
从摇动频率和摇动振幅（以及培养液与水平面的角度）获知G力，就可以预测培养物*混合的程度（直至孔的底部）一定的培养量但是，其他因素也可能会产生影响，zui明显的是表面张力（特别是与直径小于8 mm的孔有关，例如96圆孔板中的孔），以及培养液能够达到的程度。*跟随振动器的运动（尤其与24孔板中的方形孔相关，振幅较小且高频振动）。

因此，我们还使用高速摄影机制作了用于各种微孔板的摇动井的视频，这些微孔板具有不同的培养量以及摇动幅度和摇动频率的组合范围。这些视频可让您自己判断特定的振动条件是否适合您的应用。

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