| Biosensor is a special sensor which is sensitive, specific, rapid, accurate and convenient. A new kind of material, water-soluble conjugated polymer can optimize the biosensor for its conformational effects, amplification effects and electron transfer. Using conformational effect of water-soluble cationic polythiophene (PMNT) and signal amplification, several sensing strategies for the detection of environmental toxin, gen and gene mutation were designed.A lable-free Ag+ colorimetric sensing strategy was designed based on PMNT and the combination of cytosine and Ag+. Using the stategy, Ag+ was detected sensitively and selectivily. The lowest detection limit was 5μM and could be optimized to 100 nM and 83 nM respectively with Ultraviolet (UV) and fluorescencne methods. In addition, it can also work in simulation Ag+ solution, which built the foundation for the detection of Ag+ in environment. Different from other methods, the strategy is lable-free, time-saving and work with"turn on"scheme.The C-rich DNA in telomeres forms different conformations in solutions of different pH. Based on this, a colorimetric strategy for the conformational conversion of C-rich DNA induced by proton was designed based on the conformational effect of PMNT. In the strategy, as low as 40 nM C-rich DNA can be detected using UV method. In addition, cDNA was added to modify the pH response, which made it possible to apply the strategy in other ways.Using the DNA with loop-stem structure as the probe, a colorimetri strategy was designed based on the conformational effect of PMNT and a fluorescent strategy was designed based on the signal amplification of PF. In colorimetric method, a lable-free probe was used to detect the target DNA and the detection limit was 10 nM; in fluorescent method, a fluorescein (FAM) labled probe was used to detect the target DNA and the detection limit was 1 pM. In addition, single nucleotide polymorphisms (SNP) was also detected with the two strategies. |
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