AutoSampling - Automatic sampling device with integrated weight measurement

Analysis of intracellular metabolites (metabolomics) represents a key technique applied in human and biosciences for cell phenotyping and to identify health-associated biomarkers and metabolic bottlenecks, respectively. It provides therefore the ultimate basis for future novel diagnostics, pharmaceuticals, and microbial cell factories. The metabolite profile of a cell is a direct representation of the cellular phenotype and its active reaction network, a property of great value when studying cell systems. For the corresponding analytics however, several challenges arise. In the first step of the sample preparation procedure the metabolic state of the cells must be quenched. To this end a sample is transferred from the cultivation vessel into a quenching solution. Prerequisites to obtain unbiased and comparable results are a rapid transfer and an exact knowledge of the transferred sample volume because metabolite levels are comparable only after relating them to applied number of cells, which is defined by the sample volume. Currently no instrument exists that fulfills both demands. Manual transfer using a pipette is slow and requires opening of the cultivation vessel (risk of contamination by microbes or air). Different instruments have been developed in the past, with which a sample can be transferred driven by underpressure, controlled by valves or by a pump. The volume however is externally determined by calibration and must be therefore assumed for the sample. Inclusion of gas bubbles as well as pressure differences (changes in the cultivation volume, release of CO2, weather, …) lead to significant changes in the sample volume which, if not recognized, result in incorrect data. Changes in the transferred sample volume cannot be addressed by any of the known instruments. To avoid these potential sources of error, a sampling device was developed by us with which a sample is, not only rapidly and automatically transferred but the weight of the sample is determined by a mass sensor at high precision (