Gold Nanoparticle-Based Electrochemical DNA Biosensors - Electrochemical DNA Biosensors - page 123

Figure 4.9. Schematic illustration of ultrasensitive detection of glu-
tathione based on the use of Au-NPs as carriers of electrochemical labels
[52](reprinted with permission of Elsevier).
signal, glutathione could be detected in the range from 1 × 10 − 12 to
1 × 10 − 10 M, witha detection limitof 4 × 10 − 13 M.
Bio-bar code technique was also employed by Shen et al.
[16] with an electrochemical DNAzyme biosensor. The DNAzyme
hybridizes to a specially designed complementary substrate strand
thathasanoverhang,whichinturnhybridizestotheDNA-
Au bio-bar code (short oligonucleotides attached to 13-nm gold
nanoparticles).UponbindingofPb 2 + totheDNAzyme,theDNAzyme