Highly-efficient selection of interferon gamma-specific aptamers and development of a sensitive fiber-optic evanescent wave aptasensor

Interferon-gamma (IFN-γ) is a critical indicator of the immune response to many infections and diseases. Identifying excellent IFN-γ recognition molecules is of great significance for the early diagnosis and treatment of diseases. Herein, anti-IFN-γ aptamers were selected based on capillary electrophoresis-systematic evolution of ligands by exponential enrichment (CE-SELEX) and their affinities were characterized by the biolayer interferometry (BLI) assay. A rational molecular docking strategy was utilized to predict precisely the binding behavior between aptamer and IFN-γ and remove redundant bases of original sequence. Therefore, aptamer IFNG-8 with the highest affinity can be efficiently identified within only three rounds and the truncated aptamer IFNG-8 T with comparable affinity is eventually obtained. With IFNG-8 T as the detection probe, a fiber-optic evanescent wave aptasensor is constructed for the detection of IFN-γ, which shows a wide linear range from 0.1 to 10000 pM and a low limit of detection (LOD) of 0.0718 pM. The developed aptasensor exhibits high selectivity and can be utilized for IFN-γ detection in human serum samples with good recoveries. In summary, the truncated aptamer can serve as a novel optional transducing element and the developed aptasensor provides an innovative methodology for detection of IFN-γ in trace amount