This protocol describes a microfluidic platform for dynamic high-throughput analysis the phenotype of single cells. Cell-surface markers and secreted proteins are quantified and characterized by fluorescence detection using tailored immunoassays, simultaneously with measurement of other cellular characteristics, including endocytosis activity and viability.TWEET A new protocol describes a microfluidics-based assay for high-throughput interrogation of protein secretion kinetics in single cells. @BIOASTER @EyerFira @ETH_DCHAB COVER TEASER Microfluidics-based analysis of protein secretion Up to three primary research articles where the protocol has been used and/or developed.

Type of publicationArticle (peer-reviewed) An incoherent broadband cavity-enhanced absorption spectroscopy setup employing a 20 m long optical cavity is described for sensitive in situ measurements of light extinction between 630 and 690 nm. The setup was installed at the SAPHIR atmospheric simulation chamber during an intercomparison of instruments for nitrate (NO 3 ) radical detection. The long cavity was stable for the entire duration of the two week campaign. A detection limit of ∼2 pptv for NO 3 in an acquisition time of 5 s was established during that time. In addition to monitoring NO 3 , nitrogen dioxide (NO 2 ) concentrations were simultaneously retrieved and compared against concurrent measurements by a chemiluminescence detector. Some results from the campaign are presented to demonstrate the performance of the instrument in an atmosphere containing water vapor and inorganic aerosol. The spectral analysis of NO 3 and NO 2 , the concentration dependence of the water absorption cross sections, and the retrieval of aerosol extinction are discussed. The first deployment of the setup in the field is also briefly described.

Abstract. We present the first in situ detection of molecular iodine emitted from the brown macroalga Laminaria digitata under natural stress conditions. We show that the release of I 2 occurs in short, strong bursts with a complex time signature. The new data indicate that algal control of I 2 release in the form of an oscillatory time-dependence may be based on a nonlinear autocatalytic reaction scheme which is closely linked to the production of H 2 O 2 .

The emission of molecular iodine (I(2)) from the stipe, the meristematic area and the distal blade of the brown macroalga Laminaria digitata (Hudson) Lamouroux (Phaeophyceae) was monitored under low light and dark conditions. Photosynthetic parameters were determined to investigate both the extent of stress experienced by different thallus parts and the effects of emersion on photosynthesis. Immediately after air exposure, intense I(2) emission was detectable from all thallus parts. I(2) emission declined continuously over a period of 180 min following the initial burst, but was not affected by the light regime. The total number of mole of I(2) emitted by stipes was approximately 10 times higher than those emitted from other thallus parts. Initial I(2) emission rates (measured within 30 min of exposure to air) were highest for stipes (median values: 2,999 and 5,222 pmol g(-1) dw min(-1) in low light and dark, respectively) and lower, by one order of magnitude, for meristematic regions and distal blades. After exposure to air for between 60 and 180 min, I(2) emission rates of all thallus parts were reduced by 70-80%. Air exposure resulted in a decrease of the maximum photosystem II (PSII) efficiency (F(v)/F(m)) by 3%, and in a 25-55% increase of the effective PSII quantum efficiency (F(v)/F'(m)); this was caused by a higher fraction of open reaction centres (q(P)), whereas the efficiency of the latter in capturing energy (F'(v)/F'(m)) remained constant. The results indicate the presence of an iodine pool which is easily volatilised and depleted due to air exposure, even under apparently low stress conditions.