Selection and characterization of DNA aptamers for constructing colorimetric biosensor for detection of PBP2a.

Rapid and accurate diagnosis of methicillin-resistant staphylococcus aureus (MRSA) is vital for patient treatment, control of infection and monitoring epidemiology. Penicillin binding proteins (PBP2a), as an important marker protein of MRSA, has been proposed as the screening test target for tolerant bacteria of MRSA. However, current technologies based on PBP2a activity or PBP2a immunoassays were suboptimal specificity and sensitivity. In this report, the selection and characterization of DNA aptamers that binds to PBP2a was described. The DNA aptamer is with high affinity and selectivity to binding with PBP2a. Furthermore, utilizing the switched mimicking peroxidase for gold nanoparticles loaded graphene oxide (GO/Au) nanomaterials based on the effect between GO/Au and DNA, a powerful strategy was set out for designing aptamer-based colorimetric biosensor for detection of PBP2a. In this strategy, the employment of biosensor based on GO/Au and PBP2a aptamer greatly improved the detection sensitivity and selectivity with limit of detection as low as 20 nM. Accordingly, the reversible nanozyme inhibition/activation approach may be universally applicable for the biomedical diagnosis.