Liling Hao,Huajie Gu,Nuo Duan,Shijia Wu,Zhouping Wang
In this study, a highly sensitive and specific multiplex chemiluminescent method for the simultaneous detection of three antibiotics was fabricated. Thiolated hybridized complementary strand (cDNA) modified N-(4-aminobutyl)-N-ethylisoluminol (ABEI) functionalized flowerlike gold nanostructures (AuNFs) were used as signal probes. Oxytetracycline (OTC), tetracycline (TET) and kanamycin (Kana) aptamers that were fixed onto the bottom of microtiter plates were used as recognition molecules. Targets and signal probes can competitively combine with the fixed aptamers. Thus, OTC, TET and Kana can be simultaneously detected based on an ABEI–H2O2–P-iodophenol (PIP) steady-state chemiluminescence (CL) system and the CL intensity is related to the negative logarithm of the concentrations of OTC/TET/Kana, respectively. The ranges are 0.05 to 5 ng mL−1, 0.05 to 5 ng mL−1, and 0.005 to 0.5 ng mL−1, and the detection limits are 0.02, 0.02 and 0.002 ng mL−1 (S/N = 3), respectively. The capability of the bioassay in milk was also studied using the standard addition recovery method, and the results showed a good consistency with the ones that were obtained from a commercial ELISA method. Owing to the advantages of a simple operation procedure, and excellent selectivity and specificity, the proposed biosensor demonstrated great potential in the application of food safety and multiplex nanosensors.
Portable chemiluminescence (CL) imaging with a smartphone has shown a great promise for point-of-care testing of diseases, especially for acute myocardial infarction (AMI), which may occur abruptly. A challenge remains how to improve the imaging sensitivity that usually is several orders of magnitude lower than those of counterpart methodologies using the sophisticated equipment. Toward this goal, here, we report the target-triggered in situ growth of AuNP@hairpin-DNA nanoprobes into spherical nucleic acid enzymes (SNAzymes), which serve as both nanolabels and amplifiers for portable CL imaging of microRNAs (miRNAs) with an ultrahigh sensitivity comparable to that of the instrumental measurement under same conditions. A G-quadruplex (G4) DNA dense layer is dynamically produced on the gold nanocore via a DNAzyme machine-driven hairpin cleaving and captures the cofactor hemin to form the SNAzymes with higher peroxidase activity and stronger nuclease resistance than the commonly used G4 DNAzymes. The matured SNAzymes are then utilized as catalytic labels in a luminol-artesunate CL system for miRNA imaging with a smartphone as the portable detector. In this way, two AMI-related miRNAs, miRNA-499 and miRNA-133a, are successfully detected in real patients’ serum with a naked eye-visualized CL change at 10 fM, showing a 5 order of magnitude improvement on the sensitivity of visualizing the same disease markers in clinical circulating blood as compared to the reported strategy. In addition, a good selectivity of our developed CL imaging platform is demonstrated. These unique features make it promising to employ this portable imaging platform for clinical AMI diagnosis.
危险品化学品经营许可证（带存储）