A highly sensitive and selective aptamer-based colorimetric sensor for the rapid detection of PCB 77

- A colorimetric aptasensor was fabricated for PCB 77 detection for the first time.
- Truncating the nucleotides sequences was used to optimize the detection of PCB 77.
- High affinity between selected DNA sequences and PCB 77 enhanced the selectivity.
- The colorimetric detection limit reached 0.05 nM.
- PCB 77 determination in real water samples showed high accuracy and stability.

A highly sensitive, specific and simple colorimetric sensor based on aptamer was established for the detection of polychlorinated biphenyls (PCB 77). The use of unmodified gold nanoparticles as a colorimetric probe for aptamer sensors enabled the highly sensitive and selective detection of polychlorinated biphenyls (PCB 77). A linear range of 0.5 nM to 900 nM was obtained for the colorimetric assay with a minimum detection limit of 0.05 nM. In addition, by the methods of circular dichroism, UV and naked eyes, we found that the 35 base fragments retained after cutting 5 bases from the 5 'end of aptamer plays the most significant role in the PCB 77 specific recognition process. We found a novel way to truncated nucleotides to optimize the detection of PCB 77, and the selected nucleotides also could achieve high affinity with PCB 77. At the same time, the efficient detection of the PCB 77 by our colorimetric sensor in the complex environmental water samples was realized, which shows a good application prospect.