Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:3.2.1.17 (
lysozyme
)
21,489
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
In terms of how the signal varies in response to increased concentration of an analyte, sensors can be classified as either "signal-on" or "signal-off" format. While both types hold potentials to be sensitive, selective, and reusable, in many situations "signal-on" sensors are preferred for their low background signal and better selectivity. In this study, with the detection of
lysozyme
using its DNA aptamer as a trial system, for the first time we demonstrated that such an aptamer-based electrochemical biosensor can be converted from intrinsically "signal-off" to "signal-on" with the aid of a DNA exonuclease. The fact that the stepwise cleavage of antilysozyme aptamer catalyzed by
Exonuclease I
(Exo I) is entirely inhibited upon binding
lysozyme
leads to the selective removal of unbound DNA probes (thiolate anti-
lysozyme
DNA aptamer strands immobilized on gold electrode) upon the introduction of Exo I to the sensor. With the aid of electrostatically bound redox cations ([Ru(NH
3
)
6
]
3+
), we were able to quantitate the number of aptamer strands that are bound with lysozymes via conventional cyclic voltammetry (CV) measurements. We demonstrated that Exo I-assisted signal-on conversion protocol not only improves the sensing performance (10 times better limit of detection) but also promises a versatile strategy for DNA-based biosensor design, i.e., it can be readily adapted to other aptamer-protein binding systems (thrombin, as another example).
...
PMID:Exonuclease I-Assisted General Strategy to Convert Aptamer-Based Electrochemical Biosensors from "Signal-Off" to "Signal-On". 3223 11
