Colorimetric Aptasensor for Detecting Bacillus carboniphilus Using Aptamer Isolated with a Non-SELEX-Based Method

B. carboniphilus is a naphtha-degradative strain (NDS) that uses hydrocarbons for its growth and causes microbiologically influenced corrosion (MIC) in naphtha pipelines. To date, there have been no studies on receptors or sensors the detection of carboniphilus. We isolate carboniphilus-specific aptamers with non-SELEX-based method, which employs repetitive cycles centrifugation-based partitioning. The binding affinities three are evaluated by obtaining their dissociation constants (Kd), range from 13.2 to 26.3 nM. BCA-05 aptamer lowest Kd value employed two-stage label-free aptasensing platform verify selectivity using colorimetric This starts aptamer-bacteria step, concentration residual after depends amount target bacteria. Then, separated determines degree salt-induced aggregation gold nanoparticles (AuNPs), results color change red blue. AuNP expressed as ratio absorbances at 630 520 nm (A630/A520). Under optimized conditions, this aptasensor shows reliable performance linear correlation 104–107 CFU mL?1 limit 5 × 103 mL?1.