Abstract: 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 aptapers. 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.