ScholarWorks@성균관대학교

초록

Background: Conventional antigen-antibody detection methods suffer from uneven antibody distribution and low target capture rates. Nevertheless, DNA offers an inherent advantage of structural tunability. By leveraging the DNA strand displacement reaction (SDR), DNA nanostructures can be ingeniously combined with photoelectrochemical (PEC) aptamer detection to effectively overcome the aforementioned limitations. Results: Herein, an efficient “swing arm” DNA walker signal amplification strategy is designed to enhance PEC signal output. Introduction of AgInS2 quantum dots (AgInS2 QDs) into the sensing interface causes a marked decrease in the PEC signal. Upon entry of the carbohydrate antigen 15-3/aptamer (CA15-3/aptamer) complex into the sensing platform and subsequent release of the DNA probe modified with AgInS2 QDs (SP–AgInS2 QDs) from the interface, initial signal amplification is achieved. The system further employs exonuclease III (Exo III) enzymatic digestion to convert a “static” DNA tetrahedron (TDN) into a “swing arm” TDN, enabling multiple rounds of signal amplification. The resulting PEC aptamer sensor exhibits an excellent linear range (0.0001 - 200 U/mL) and a detection limit of 0.027 mU/mL. Significance: The designed strategy integrates “swing arm” TDN walkers with an aptamer sensor possessing high recognition capability. The strategy exploits the unique advantages of DNA nanostructures for signal cascade amplification and improved target capture rates. Furthermore, the sensing platform can be extended to other analytes by appropriately modifying the base sequences.

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