The invention relates to a preparing method of
a DNA determining electrochemical sensor based on a
platinum nano particle
catalysis electrochemistry circulation
signal amplification technology and the application of the electrochemical sensor. A hairpin
DNA 1 is assembled on the surface of a
platinum nano particle modified gold
electrode in a self-
assembly mode, and when a target
DNA 2 exists, due to the fact that the target
DNA 2 and the hairpin DNA 1 assembled on the surface of the gold
electrode are partially paired in a complementary mode, the hairpin structure of the DNA 1 is opened. Then, another hairpin DNA 3 chain replaces the target chain DNA 2 by competing
pairing hybridization, the target chain DNA 2 is released, and the released target chain is continuously opened to form a new hairpin structure. The action is carried out in a
cycling mode, recycling of the target chain DNA 2 is achieved, a prepared nano particle electrochemical probe is combined,
signal amplification is achieved, the prepared electrochemical sensor is used for catalyzing
cycling between PAP and PQI, further
electrochemistry signal amplification is achieved, a
cyclic voltammetry or DPV is used for determining current
signal intensity, and according to the measured current
signal intensity, determining on the target chain DNA2 is achieved. The sensor has high detecting sensitivity.