Protein-Processing Platform (3P) - a New Concept for the Characterization of Cell Cultures in the mL-Scale Using Microfluidic Components

A newly developed Protein‐Processing Platform (3P) for cell cultivation and sample handling is presented. The 3P‐concept is based on a 6‐well microtiter plate for cell cultivation, an autoclavable top plate as a sampling system using a new kind of microvalve and an x‐y‐z‐plotter to manage the sample handling procedures. Furthermore, the sample can be stored in a water‐cooled deep well plate and transported to a detector e.g. by addressing a dedicated protein chip based on a Black‐Silicon structure. The function of microvalves is based on the swelling behavior of hydrogel depending on its temperature. The regulation system of this temperature is integrated into the 6‐well microtiter top plate. In this paper, the realization of this concept is exemplarily carried out using the cultivation of hybridoma and their production of monoclonal antibodies. The cultivation conditions were not optimized. However, using different mixing methods, their influence on the antibody production was investigated. The best cell growth was observed in the dormant 6‐well microtiter plate. As under these conditions, a gradient of antibody concentrations occurs, the depth of immersion of the sampling probes has to be investigated. A reproducible sampling was possible by withdrawing the sample from the middle of the cell suspension level. Procedures for sampling and washing under sterile conditions were developed using the tools of the x‐y‐z‐plotter. The optical detection of the samples can be performed using the new protein chip based on the Black‐Silicon technology in any kind of commercial reader. It is possible to integrate the single modular components of the platform into every protein expression process. Additionally, the adaptation of the sampling system to commercial microtiter plates guarantees a wide range of applications. The newly developed “Protein‐Processing Platform” concept is presented for the use in cell cultivation and sample handling, including transport, storage, and detection. Microfluidic components, like autoclavable microvalves, enable withdrawing μL samples from bioreactors on a mL to a pilot scale.