Triplex signal amplification for electrochemical DNA biosensing by coupling probe-gold nanoparticles-graphene modified electrode with enzyme functionalized carbon sphere as tracer.
An ultrasensitive electrochemical DNA biosensor was constructed by assembling probe labeled gold nanoparticles (ssDNA-AuNP) on electrochemically reduced graphene oxide (ERGO) modified electrode with thiol group tagged (GT) DNA strand (d(GT)(29)SH) and coupling with horseradish peroxidase (HRP) functionalized carbon sphere (CNS) as tracer. The heteronanostructure formed on the biosensor surface appeared relatively good conductor for accelerating the electron transfer, while the HRP tagged CNS provided dual signal amplification for electrochemical biosensing. The triplex signal amplification strategy produced an ultrasensitive electrochemical detection of DNA down to attomolar level (5 aM) with a linear range of 5 orders of magnitude (from 1 × 10(-17)M to 1 × 10(-13)M), and appeared high selectivity to differentiate single-base mismatched and three-base mismatched sequences of DNA. The proposed approach provided a simple and reliable method for DNA detection with high sensitivity and specificity, indicating promising application in bioanalysis and biomedicine.
State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093, PR China.
Haifeng
H
Dong
Zhu
Z
Zhu
Huangxian
H
Ju
Feng
F
Yan
D015374:Biosensing Techniques / Q000379:methods*; D002244:Carbon / Q000737:chemistry; D004247:DNA / Q000032:analysis*; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D012680:Sensitivity and Specificity
D002244:Carbon; D006046:Gold; D006108:Graphite; D004247:DNA; D006735:Horseradish Peroxidase