Panpan Huang, Jie Tan, Wenlin Gong, Zhenghua Zhang, Rong Zheng, Chaofan Zhou, Guoqing Zhang, Wenxiu Dai, Siyu Wu, Ying Zhang, Yong Huang, Sufang Zhou, Yongxiang Zhao
A simple and rapid colorimetric method for determination of alpha-fetoprotein (AFP) has been developed here using specific aptamers and free gold nanoparticles (AuNPs). In the absence of AFP, the free aptamers prevent aggregation of AuNPs in a high salt environment, which cause the mixed solution remain red. Conversely, when there are existing AFP in colorimetric system, the aptamers is consumed to decrease, forming aptamer-AFP complex. AuNPs were aggregated due to losting the protection from aptamers in the high salt solution. The color of the solution turns to blue at this time. Subsequently, a color change of red-to-blue can be observed by the naked eye with the increasing of AFP. The linear response range for AFP was 10 to 2000 ng/ml and the detection limit was 5 ng/ml. This colorimetric biosenser does not require any modification, and its composition is cheap and easy to obtain. In addition, this proposed colorimetric method is also used in simulative hepatocellular carcinoma (HCC) serum samples and showed good feasibility, holding great potential for preliminary screening of serum of HCC in the future.
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