[Selection and identification of ssDNA aptamers specific to clinical isolates of Streptococcus mutans strains with different cariogenicity].

Objective: To select and identify ssDNA aptamers specific to Streptococcus mutans strains with different cariogenicity isolated from clinical specimens.

Methods: Subtractive SELEX technology targeting the whole intact cells was used to screen for ssDNA aptamers specific to the clinical isolates Streptococcus mutans strains with different cariogenicity. Radioactive isotope, flow cytometry, gene cloning and sequencing, MEME online software and RNA structure analysis software were employed to analyze the first and secondary structures of the aptamers and identify the screened aptamers.

Results: Detection by radioactive isotope showed sufficient pool enrichment after 9 rounds of subtractive SELEX. Flow cytometry showed that the selected aptamers H1, H16, H4, L1, L10 and H19 were capable of binding specifically with highly cariogenic Streptococcus mutans strains but not with strains with a low cariogenicity. The aptamer H19 had the strongest binding capacity to highly cariogenic Streptococcus mutans strains, with a dissociation constant of 69.45∓38.53 nmol/L.

Conclusion: We have obtained the ssDNA aptamers specific to the clinical isolates of highly cariogenic Streptococcus mutans strains.