Purification of quantum dot-based bioprobes via high-performance size exclusion chromatography

• First, monodisperse OPA-QDs were obtained by purified with high-performance size exclusion chromatography (HPSEC) to remove excess OPA and aggregated QDs.
• Secondly, excess free streptavidin (SA) in fresh prepared QD-labeled SA, and the monodisepese QD-SA were used in tumour maker determination.
• Thirdly, monodisperse QD-labeled antibody bioprobes has been obtained by removing away the unbound antibody and suspended agglomerates of QDs at the same time via high-performance size exclusion chromatography (HPSEC).

Due to excellent optical properties, quantum dots (QDs) have been widely applied to sensing, labeling, and imaging. For the fabrication of QD-based bioprobes, purification is usually the crucial step. Hydrophilic octylamine grafted polyacrylic acid modified QDs (OPA-QDs) were prepared, and purified by high-performance size exclusion chromatography (HPSEC) to remove excess OPA and aggregated QDs. The percentage of suspended agglomerates of OPA-QDs in the unpurified OPA-QDs increases from 4% to 31% through a year, but the purified OPA-QDs of the same batch possess excellent colloidal stability for at least one year. Subsequently, QD-based bioprobes were fabricated by the conjugation between QDs and streptavidin (SA) or antibody (IgG), generating QD-SA and QD-IgG, respectively, which were purified via HPSEC. Finally, the resulting QD-SA and QD-IgG were adopted to detect tumour markers on slices and showed specific positive signals without nonspecific adsorption, which was contrary to the unpurified QD-IgG. Thus, the HPSEC-coupled system proposed in the current work is potent and universal for the generation of purified and monodisperse QD-based bioprobes, which is promising in the nanobiodetection field.

QD-based bioprobes were purified via high-performance size exclusion chromatography to improve the specificity for target imaging.Figure optionsDownload as PowerPoint slide