An enhanced chemiluminescence resonance energy transfer aptasensor based on rolling circle amplification and WS2 nanosheet for Staphylococcus aureus detection

- Co2+ enhanced ABEI functional flowerlike gold nanoparticles (Co2+/ABEI-AuNFs) was first used as chemiluminescent donor.
- Rolling circle amplification (RCA) technique was also applied in the WS2 nanosheet based CRET system for the first time.
- The improved WS2 nanosheet based CRET platform can overcome the limitation that only DNA or RNA can be detected and expand the detection scope.
- A steady-state CRET aptasensor based on P-Iodophenol (PIP) and RCA was fabricated to detect S. aureus with high sensitivity and specificity.

A chemiluminescence resonance energy transfer aptasensor was fabricated for the detection of Staphylococcus aureus (S. aureus) with Co2+ enhanced N-(aminobutyl)-N-(ethylisoluminol) (ABEI) functional flowerlike gold nanoparticles (Co2+/ABEI-AuNFs) as donor and WS2 nanosheet as acceptor. In the presence of S. aureus, rolling circle amplification (RCA) can be started. Partially complementary sequence of RCA product functional ABEI-AuNFs (cDNA-ABEI-AuNFs) were then annealed to multiple sites of the RCA product to form duplex complex. This complex is less adsorbed onto the WS2 nanosheet, thus attenuating the quenching of ABEI-AuNFs chemiluminescence by WS2 nanosheet. In the absence of target S. aureus (and hence the absence of RCA and duplex formation), the free cDNA-ABEI-AuNFs is completely adsorbed onto the WS2 nanosheet and chemiluminescence quenching ensues. Under optimal conditions, the logarithmic correlation between the concentration of S. aureus and the CL signal was found to be linear within the range of 50 cfu/mL to 1.5 × 105 cfu/mL (R2 = 0.9913). The limits of detection of the developed method were found to be 15 cfu/mL for S. aureus. The selectivity and the capability of the biosensor in meat samples were also studied. Therefore, this simple and easy operation method can be used to detect S. aureus with high sensitivity and specificity.

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