Microfluidic devices capable of manipulating and guiding small fluid volumes open new methodical approaches in the fields of biology, pharmacy, and medicine. They have already proven their extraordinary value for cell analysis. The emergence of microfluidic platforms has paved the way to novel analytical strategies for the positioning, treatment and observation of living cells, for the creation of chemically defined liquid environments, and for tailoring biomechanical or physical conditions in small volumes. In this article, we particularly focus on two complementary approaches: (i) the isolation of cells in small chambers defined by microchannels and integrated valves and (ii) the encapsulation of cells in microdroplets. We review the advantages and limitations of both approaches and discuss their potential for single-cell analysis and related fields. Our intention is also to give a recommendation on which platform is most appropriate for a new question, i.e., a guideline to choose the most suitable platform.

Production of the Alternaria mycotoxins alternariol (AOH), alternariol monomethylether (AME) and tenuazonic acid (TA) by Alternaria alternata DSM 12633 was influenced by pH and carbon to nitrogen (C:N) ratio of the growth medium both in shaking flasks and bioreactor cultivation. The impact of medium pH on mycotoxin production was studied in the range of pH 3.5 - 8. pH values above 5.5 led to a decreased mycotoxin production or inhibited mycotoxin formation completely whereas an acidic pH in the range of 4.0-4.5 was optimal for mycotoxin production. The influence of the C:N ratio was evaluated over the range of 24 to 96. Glucose was used as carbon source and its concentration was altered while nitrogen concentration was kept constant. Growth kinetics and mycotoxin production parameters were studied depending on different C:N ratios. With increasing initial glucose concentration fungal biomass did increase but the maximum specific growth rate was not influenced. The optimal initial C:N ratio for attaining highest mycotoxin concentrations was 72. A higher C:N ratio did not further enhance mycotoxin production.

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