One of the crucial, manual sample preparation steps in the PCR process is removing the final amplified product from the PCR plates following the thermal cycling procedure. If these liquid handling steps are not performed accurately, PCR yield will be significantly affected.

Solution: It is widely known that centrifugation of PCR plates before and after the thermal cycling process aids in positioning the liquid reagent samples at their proper locations in the bottom of the sample wells. Inconsistent or imprecise pipetting of the samples into the plates during PCR set up can lead to small droplets of solution on the side walls of the plate wells (see figure 1). Incomplete mixture of the reaction reagents and target DNA samples, in this case, can and will lead to poor amplification results. Another common problem when pipetting such small volumes of samples into the plate wells is the formation of bubbles in the samples. Bubble formation leads to non-uniform contact of the samples to the surface of the plastic wells, and this can cause poor or inconsistent heat transfer during the thermal cycling process. Centrifugation of the plate prior to thermal cycling brings the entire quantity of reagent mixture to the bottom tips of each of the conical wells, ensuring a wellmixed sample and concentration of all reagent components and removal of any bubbles.

There are many commercially available centrifuges for spinning 96-well microtiter plates, and PCR plates. These typically use a large, expensive swing out rotor, with plate holding trays. Most of these centrifuges are designed to accept a variety of different rotors, have sophisticated electronic control systems, and take up valuable lab bench space.

One alternative to such units is Labnet International’s MPS- 1000 Mini Plate Spinner centrifuge, which is designed specifically for quickly spinning down PCR plates before and after a PCR reaction. Unlike standard benchtop centrifuges with microplate rotors, this plate spinner is compact in design and simple to operate. Sealed PCR plates are inserted vertically into the instrument, and the surface tension of the small samples keeps them from moving within the sample wells. The spinner accommodates all standard plate sizes or ½ plates, strips, or tubes when using the optional adapter. The entire centrifuge process is quick, easy, cost effective, and results in a guaranteed homogeneous sample mixture.

For more information, please contact Labnet International, Inc. at: labnetinfo@corning.com, www.labnetinternational.com, or 732-417-0700