Forster resonance energy transfer analysis of quantum dots and peptide self-assembly inside a capillary

We have developed a new method using fluorescence coupled capillary electrophoresis (CE-FL) for monitoring self-assembly of quantum dots (QDs) and ATTO 590 labeled peptide (ATTO-EA(5)H(6)) inside a capillary. QDs and ATTO-EA(5)H(6) were sequentially injected into the capillary, thereafter they mixed and self-assembled inside the capillary. Such in-capillary self-assembly was driven by a metal-affinity force which yielded a new fluorescence signal due to Forster resonance energy transfer (FRET). CE-FL was used to measure and record the self-assembly status and rate with electrophoretograms under various conditions. Recorded electrophoretograms have shown that in-capillary assay gave out different patterns of the assembly compared to out-capillary assay. The efficiency of the QDs and ATTO-EA(5)H(6) self-assembly on in-capillary assay was affected by the molar ratio and the time interval of injection. More importantly, the in-capillary assay could be applied to detect the stability of QD-ATTO-EA(5)H(6) assembly. The results indicated that high concentration of imidazole (Im) could displace a portion of ATTO-EA(5)H(6) on QDs surface. This assay could further expand the application of FRET in the field of QDs-based online bioanalysis. (C) 2016 Elsevier B.V. All rights reserved.