Ultrafiltration as an alternative purification method for bovine serum albumin-fluorescein isothiocyanate bioconjugate.

The bioconjugation of proteins with fluorescent probes is a popular method for protein visualization and has widespread applications across scientific fields. This study assessed ultrafiltration as an alternative purification method following the bioconjugation reaction that tags fluorescein isothiocyanate (FITC) to bovine serum albumin (BSA). Success of the purification was determined by (1) UV-Vis spectroscopy, comparing our sample to a commercially available product, and (2) use in an in vitro bioassay. Centrifugal ultrafiltration devices with a molecular weight cut off below the molecular weight of the conjugated protein were successful in retaining the purified product and clearing unreacted FITC from solution.