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.

中文翻译：

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通过高性能尺寸排阻色谱法纯化基于量子点的生物探针。

由于出色的光学性能，量子点（QD）已广泛应用于传感，标记和成像。对于基于QD的生物探针的制造，纯化通常是至关重要的步骤。制备了亲水性辛胺接枝的聚丙烯酸改性的量子点（OPA-QDs），并通过高性能尺寸排阻色谱法（HPSEC）进行纯化，以去除过量的OPA和聚集的量子点。未纯化的OPA-QD中悬浮的OPA-QD附聚物的百分比在一年内从4％增加到31％，但是同一批次的纯化的OPA-QD具有良好的胶体稳定性至少一年。随后，通过QD与链霉亲和素（SA）或抗体（IgG）之间的结合来制备基于QD的生物探针，分别生成QD-SA和QD-IgG，并通过HPSEC对其进行纯化。最后，所得的QD-SA和QD-IgG被用于检测切片上的肿瘤标志物，并显示出特定的阳性信号而没有非特异性的吸附，这与未纯化的QD-IgG相反。因此，当前工作中提出的HPSEC耦合系统对于产生纯化的和单分散的基于QD的生物探针是有效且通用的，这在纳米生物检测领域很有希望。