Zhao Ruirui, Zhao Lu, Feng Haidi, Chen Xiaoliang, Zhang Huilin, Bai Yunfeng, Feng Feng, Shuang Shaomin
College of Chemistry and Chemical Engineering, Institute of Environmental Science, Shanxi University, Taiyuan, 030006, China.
College of Chemistry and Environmental Engineering, Shanxi Datong University, Datong, 037009, China.
Analyst. 2021 Feb 22;146(4):1340-1345. doi: 10.1039/d0an02188a.
Prostate specific antigen (PSA) has been considered as the most potential serological biomarker for the early stage detection of prostate cancer. Here, a label-free fluorescence aptasensing strategy for detecting PSA based on hybridization chain reaction (HCR) and G-quadruplex DNAzymes has been developed. This designed strategy consists of three DNA probes, aptamer probe (AP), hairpin probe 1 (H1) and hairpin probe 2 (H2). In the presence of target PSA, the aptamer sequences in AP specifically recognized PSA to form a PSA-aptamer complex, causing an AP conformation change and thus releasing the initiator, which triggered the chain-like assembly of H1 and H2 that yielded extended nicked double-stranded DNA through HCR. Upon the addition of hemin, the G-rich segments at the end of H1 and H2 self-assembled into the peroxidase-mimicking hemin/G-quadruplex DNAzymes, which catalyzed the hydrogen peroxide-mediated oxidation of thiamine to give a fluorescence signal dependent on the concentration of PSA. Under optimal conditions, a limit of detection of 0.05 nM and a linear range from 0.1 nM to 1 nM (R2 = 0.9942) were achieved by this assay. In addition, other interfering proteins, such as IgG, AFP and CEA, did not produce any significant change in the fluorescence intensity response, indicating good selectivity of this sensor for PSA detection. Finally, this proposed aptasensor was successfully used for diluted serum samples.
前列腺特异性抗原（PSA）一直被认为是前列腺癌早期检测中最具潜力的血清生物标志物。在此，基于杂交链式反应（HCR）和G-四链体DNA酶开发了一种用于检测PSA的无标记荧光适配体传感策略。该设计策略由三种DNA探针组成，即适配体探针（AP）、发夹探针1（H1）和发夹探针2（H2）。在目标PSA存在的情况下，AP中的适配体序列特异性识别PSA以形成PSA-适配体复合物，导致AP构象改变，从而释放引发剂，引发H1和H2的链式组装，通过HCR产生延伸的带切口双链DNA。加入血红素后，H1和H2末端富含G的片段自组装成模拟过氧化物酶的血红素/G-四链体DNA酶，催化过氧化氢介导的硫胺氧化，产生依赖于PSA浓度的荧光信号。在最佳条件下，该检测方法的检测限为0.05 nM，线性范围为0.1 nM至1 nM（R2 = 0.9942）。此外，其他干扰蛋白，如IgG、AFP和CEA，在荧光强度响应中未产生任何显著变化，表明该传感器对PSA检测具有良好的选择性。最后，该提出的适配体传感器成功用于稀释的血清样本。
