摘要
The dye-doped silica nanoparticles can be used as nanobiosensors that are able to recognize and detect specific DNA sequence. In this paper, spherical nanosized luminol/SiO2 composite particles have been synthesized with reverse micells via hydrolysis of tetraethyl orthosilicate (TEOS) in the microemulsion. The nanoparticles were modified with chitosan and used to label DNA, forming the DNA probe which was used to hybridize with target DNA immobilized on a PPy modified Pt electrode. The hybridization events were evaluated by electrogenerated chemiluminescence (ECL) measurements and only the complementary sequence could form a double-stranded DNA (dsDNA) with DNA probe and give strong ECL signals. A three base mismatch sequence and a non-complementary sequence had almost negligible responses. Due to the large number of luminol molecules inside silica nanoparticles, the assay allows detection at levels as low as 2.0×10-12 mol/L of the target DNA. The intensity of ECL was linearly related to the concentration of the complementary sequence in the range of 5.0×10-12—1.0×10-9 mol/L.
The dye-doped silica nanoparticles can be used as nanobiosensors that are able to recognize and detect specific DNA sequence. In this paper, spherical nanosized luminol/SiO2 composite particles have been synthesized with reverse micells via hydrolysis of tetraethyl orthosilicate (TEOS) in the microemulsion. The nanoparticles were modified with chitosan and used to label DNA, forming the DNA probe which was used to hybridize with target DNA immobilized on a PPy modified Pt electrode. The hybridization events were evaluated by electrogenerated chemiluminescence (ECL) measurements and only the complementary sequence could form a double-stranded DNA (dsDNA) with DNA probe and give strong ECL signals. A three base mismatch sequence and a non-complementary sequence had almost negligible responses. Due to the large number of luminol molecules inside silica nanoparticles, the assay allows detection at levels as low as 2.0×10-12 mol/L of the target DNA. The intensity of ECL was linearly related to the concentration of the complementary sequence in the range of 5.0×10-12—1.0×10-9 mol/L.
基金
Project supported by the National Natural Science Foundation of China (No. 29975010).
