iBB

Rapid empirical optimization/screening of the partition of biomolecules in aqueous two-phase systems (ATPS) can be performed in microfluidic devices coupled with fluorescence microscopy. However, the effect of fluorescent tags on partition must be carefully evaluated to assess the validity of extrapolating the results to a situation where the molecules are unlabelled. To evaluate this influence, researchers from BERG-iBB and INESC-MN (Mariana São Pedro, Ana Azevedo, Maria Raquel Aires-Barros and Ruben Soares) carried out an ATPS study using both microtubes (batch) and microfluidic devices (continuous). IgG molecules were labelled with three fluorescent tags with different global charge and reactivity, namely BODIPY™ FL maleimide, Alexa Fluor® 430 NHS ester and BODIPY™ FL NHS ester. The thiol reactive BODIPY™ FL maleimide coupled with a reducing agent provided minimal bias relative to the native molecule in PEG-phosphate systems. The work was recently published in the Biotechnology Journal.