A new aptamer/SWNTs IDE-SPQC sensor for rapid and specific detection of Group A Streptococcus

Rapid and accurate detection of Group A Streptococcus (GAS) infection is very important in clinical diagnosis. In this paper, a new aptamer/SWNTs interdigital gold electrode piezoelectric sensor was constructed for detection of GAS. The selected anti-GAS aptamer was used as recognition probe and single-walled carbon nanotubes (SWNTs) immobilized on the Interdigital Gold Electrode (IDE) was used as electron transducer which connected to piezoelectric quartz crystal (SPQC) in series. The response mechanism of constructed sensor was based on the fact that GAS specifically reacted with anti-GAS aptamer immobilized on SWNTs IDE and caused aptamer detaching from SWNTs IDE and resulted sensitively frequency shift response of IDE-SPQC. The frequency shift of constructed sensor had a linear relationship with the concentration of GAS in the range of 3 × 102 cfu/ml to 3 × 106 cfu/ml. The detection limit was 12 cfu/ml GAS. The detection time was less than 40 min. The recovery rate for detection of GAS in milk was 76–97% using constructed sensor. It would find application in clinical diagnosis and environment for rapid detection of GAS.