title: Ultrasensitive electrochemical biosensing for DNA using quantum dots combined with restriction endonuclease.
abstract: A universal and sensitive electrochemical biosensing platform for the detection and identification of DNA using CdSe quantum dots (CdSe QDs) as signal markers was designed. The detection mechanism was based on the specific recognition of MspI endonuclease combined with the signal amplification of gold nanoparticles (AuNPs). MspI endonuclease could recognize its specific sequence in the double-strand DNA (dsDNA) and cleave the dsDNA fragments linked with CdSe QDs from the electrode. The remaining attached CdSe QDs can be easily read out by square-wave voltammetry using an electrodeposited bismuth (Bi) film-modified glass carbon electrode. The concentrations of target DNA could be simultaneously detected by the signal of metal markers. Using mycobacterium tuberculosis (Mtb) DNA as a model, under the optimal conditions, the proposed biosensor could detect Mtb DNA down to 8.7 × 10(-15) M with a linear range of 5 orders of magnitude (from 1.0 × 10(-14) to 1.0 × 10(-9) M) and discriminate mismatched DNA with high selectivity. This strategy presented a universal and convenient biosensing platform for DNA assay, and its satisfactory performances make it a potential candidate for the early diagnosis of gene-related diseases.
authors.affiliation: Jiangsu Key Laboratory of Biofunctional Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210023, P. R. China. daizhihuii@njnu.edu.cn.
authors.forename: Can
authors.initials: C
authors.lastname: Zhang
authors.forename: Jing
authors.initials: J
authors.lastname: Lou
authors.forename: Wenwen
authors.initials: W
authors.lastname: Tu
authors.forename: Jianchun
authors.initials: J
authors.lastname: Bao
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Dai
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D019187:Cadmium Compounds / Q000737:chemistry; D004269:DNA, Bacterial / Q000032:analysis* / Q000235:genetics; D019003:Deoxyribonuclease HpaII / Q000378:metabolism*; D055664:Electrochemical Techniques / Q000379:methods; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D009169:Mycobacterium tuberculosis / Q000235:genetics; D045663:Quantum Dots / Q000737:chemistry*; D018036:Selenium Compounds / Q000737:chemistry; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*
chemical_list: D019187:Cadmium Compounds; D004269:DNA, Bacterial; D018036:Selenium Compounds; D006046:Gold; C058667:cadmium selenide; D019003:Deoxyribonuclease HpaII