College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University , Qingdao 266109, People's Republic of China.
Anal Chem. 2017 Sep 5;89(17):9100-9107. doi: 10.1021/acs.analchem.7b01797. Epub 2017 Aug 18.
The development of ultrasensitive and highly selective fluorescence biosensors for diverse analytes is highly desirable but remains a challenge. It is attributable to the scarcity of fluorogens with promising brightness, stability, and nontoxicity, which primarily determine the performance of fluorescence biosensors. Herein, we report the design and preparation of aggregation induced emission (AIE) dots with high brightness, exceptional colloidal stability, ultrasmall size, and functional groups for developing ultrasensitive biosensor through the electrostatic conjugation to biological molecules, and use blemycin (BLM) as the proof-of-concept analyte. The recognition and the subsequent cleavage of the quencher-labeled DNA (Q-DNA) by BLM result in the formation of three-mer quencher-linked oligonucleotide fragments (Q-DNA-1), which significantly decreases the amount of quenchers anchored on AIE dot surfaces and subsequently reduces the fluorescence resonance energy transfer (FRET) effect. As compared to the case in which BLM is absent, remarkable fluorescence enhancement is observed, and is dependent on BLM concentration. Thus, ultrasensitive fluorescence detection of target BLM is realized, with a detection limit down to 3.4 fM, the lowest value reported so far. Moreover, the proposed fluorescence biosensor has also been successfully utilized for detection of BLM spiked in human serum samples. The as-proposed strategy not only significantly improves the selectivity and sensitivity of BLM assay, but also allows the ultrasensitive detection of a variety of bioactive molecules by simply changing the specific target recognition substances, thus providing a versatile fluorescence platform, and showing great potential to be applied in chemo-/bioanalysis and clinical biomedicine.
开发针对各种分析物的高灵敏度和高选择性荧光生物传感器是非常需要的，但仍然是一个挑战。这是由于具有良好亮度、稳定性和低毒性的荧光团的稀缺性，这些特性主要决定了荧光生物传感器的性能。在此，我们报告了具有高亮度、优异胶体稳定性、超小尺寸和功能基团的聚集诱导发射（AIE）点的设计和制备，通过静电共轭将生物分子用于开发超灵敏生物传感器，并使用 blemycin（BLM）作为概念验证分析物。BLM 对标记淬灭剂的 DNA（Q-DNA）的识别和随后的切割导致三mer 淬灭剂连接寡核苷酸片段（Q-DNA-1）的形成，这大大减少了锚定在 AIE 点表面的淬灭剂的数量，从而减少了荧光共振能量转移（FRET）效应。与 BLM 不存在的情况相比，观察到明显的荧光增强，并且依赖于 BLM 浓度。因此，实现了对目标 BLM 的超灵敏荧光检测，检测限低至 3.4 fM，这是迄今为止报道的最低值。此外，所提出的荧光生物传感器还成功用于检测人血清样品中添加的 BLM。所提出的策略不仅显著提高了 BLM 测定的选择性和灵敏度，而且通过简单改变特定的靶标识别物质，还允许对各种生物活性分子进行超灵敏检测，从而提供了一种通用的荧光平台，并显示出在化学/生物分析和临床生物医学中应用的巨大潜力。
