Ultrasensitive electrochemiluminescence detection of DNA based on nanoporous gold electrode and PdCu@carbon nanocrystal composites as labels.
A sensitive electrochemiluminescence (ECL) DNA biosensor based on nanoporous gold (NPG) electrode and PdCu@carbon nanocrystals (CNCs) composites is developed. The CNCs were obtained simply by electrooxidation with abundant carboxyl groups at their surfaces. The NPG can be easily prepared by a selective dissolution of silver from silver-gold alloy in nitric acid, which has free-standing noble metal membranes with controllable three-dimensional (3D) porosity. The PdCu bimetallic nanocomposites with hierarchically hollow structures were fabricated through a simple replacement reaction using dealloyed nanoporous copper (NPC) as both a template and reducing agent. Structure characterization was obtained by means of transmission electron microscope (TEM) and scanning electron microscope (SEM) images. The PdCu@CNCs composites exhibit 6 times higher ECL intensity than the pure CNC-labeled reporter DNA. Taking advantage of dual-amplification effects of the developed probe, a limit of detection as low as 18 aM can be achieved and the assay exhibits excellent selectivity for single-mismatched DNA detection even in human serum. The proposed ECL based method should have wide applications in diagnosis of genetic diseases due to its simplicity, low cost, and high sensitivity at extremely low concentrations.
Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong(University of Jinan), Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China.
Mei
M
Yan
Meng
M
Zhang
Shenguang
S
Ge
Jinghua
J
Yu
Meng
M
Li
Jiadong
J
Huang
Su
S
Liu
D000497:Alloys / Q000737:chemistry; D020137:Base Pair Mismatch; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002244:Carbon / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D004247:DNA / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D004563:Electrochemistry; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D057230:Limit of Detection; D049408:Luminescent Agents / Q000737:chemistry; D008163:Luminescent Measurements; D053768:Metal Nanoparticles / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D016062:Porosity; D015203:Reproducibility of Results
D000497:Alloys; D049408:Luminescent Agents; D010165:Palladium; D002244:Carbon; D006046:Gold; D003300:Copper; D004247:DNA