Synthesis and characteristics of fluorescent red-emitting DNA-templated silver nanoclusters based on aptamer selected to lung cancer

Abstract

In recent years, there have been a lot of papers and reports on the DNA-templated silver nanoclusters. These nanoclusters are ultra-bright and stable fluorescent beacons. Application of DNA-templated silver nanoclusters for biomolecules detection and bioimaging seems promising. However, direct conjugation between DNA-templated silver nanoclusters and antibodies is complicated while nanoclusters tend to degrade under conjugation conditions. To overcome this problem, it is possible to create a probe that not only can serve as an fluorescence reporter but also can contain the recognition motif that could selectively bind with target biomolecules. In the present work, we developed DNA-templated silver nanoclusters based on aptamer to lung cancer. Various sequences were added to core aptamer nucleotide sequence to form fluorescent nanoclusters. The synthesis of DNA-templated silver nanoclusters using borohydride reduction was conducted. Nanoclusters with 567 nm excitation and 630 nm emission were produced. The fluorescence quantum yield was 32 %. The storage technique of DNA-templated silver nanoclusters was optimized to ensure their photostability during the storage. Thus, bright and stable fluorescent red-emitting DNA-templated silver nanoclusters based on novel aptamer to lung cancer were developed. However, the potential use of DNA Ag NC for cell staining is complicated by the partial quenching of DNA Ag NC fluorescence in the presence of biomolecules.