Key Laboratory of Modern Agricultural Equipment and Technology, Ministry of Education, School of Agricultural Engineering, Jiangsu University, Zhenjiang, Jiangsu, 212013, China.
Key Laboratory of Modern Agricultural Equipment and Technology, Ministry of Education, School of Agricultural Engineering, Jiangsu University, Zhenjiang, Jiangsu, 212013, China.
Biosens Bioelectron. 2022 Jan 1;195:113634. doi: 10.1016/j.bios.2021.113634. Epub 2021 Sep 21.
Aptamer-based sensor with high-specificity typically has a fixed linear range due to the host-guest binding. To expand the dynamic range for multiple scenarios, we report here a dual-ratiometric electrochemical aptasensor that integrates two aptamer profiles with varied affinity into a single sensing interface for aflatoxin B1 (AFB1) detection. Using functional aptamer as recognition element and generator of signals, we fabricate the dual-ratiometric aptasensor with anthraquinone loaded reduced graphene oxide (AQ-rGO), methylene blue labeled hairpin DNA (MB-DNA), and ferrocene labeled linear aptamer (Fc-apt), using MB and Fc probes to work in tandem while AQ as reference. The current of Fc (I) is used to detect the low-concentration analyte, and that of MB (I) varies when the concentration of AFB1 reaches a threshold. The threshold switch for I could be tuned by engineering the quantity ratio of Fc-apt and MB-DNA (a ratio of 1:1 is used here). The aptasensor can rapidly achieve the positive (+)/negative (-) detection of AFB1 with a threshold concentration of 10 pg mL, while the quantitative detection employs the ratio of current of AQ, MB, and Fc (i.e., I/I and I/I) as yardsticks, offering two linear ranges of 10-10 and 10-5 × 10 pg mL, respectively. The aptasensor is successfully used to monitor the amount of AFB1 in a 7-days mildew process of peanut. Such a protocol opens a new way for the design of sensors with the programmable linear range in the advanced biological and chemical sensing.
基于适配体的传感器通常具有固定的线性范围，因为它是基于主客体结合的。为了在多个场景下扩展动态范围，我们在此报告了一种双比率电化学适体传感器，它将两种具有不同亲和力的适体图谱集成到单个传感界面中，用于检测黄曲霉毒素 B1 (AFB1)。我们使用功能适配体作为识别元件和信号发生器，制备了双比率适体传感器，其中包含负载蒽醌的还原氧化石墨烯 (AQ-rGO)、亚甲基蓝标记发夹 DNA (MB-DNA) 和二茂铁标记线性适配体 (Fc-apt)，使用 MB 和 Fc 探针串联工作，而 AQ 则作为参考。Fc (I) 的电流用于检测低浓度分析物，而当 AFB1 的浓度达到阈值时，MB (I) 的电流会发生变化。通过工程化 Fc-apt 和 MB-DNA 的量比（这里使用 1:1 的比例），可以调整 I 的阈值开关。该适体传感器可以快速实现 AFB1 的正 (+)/负 (-) 检测，其阈值浓度为 10 pg mL，而定量检测则采用 AQ、MB 和 Fc 的电流比值 (即 I/I 和 I/I) 作为标准，分别提供 10-10 和 10-5×10 pg mL 的两个线性范围。该适体传感器成功用于监测花生 7 天霉变过程中 AFB1 的含量。这种方案为可编程线性范围的生物和化学传感器的设计开辟了新途径。
