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.
As a nano-form of G-quadruplex (G4) based DNAzymes, spherical nucleic acid enzymes (SNAzymes) with gold nanoparticles (AuNPs) as cores have shown great promise for applications in nucleic acid detection. SNAzymes can be constructed by modifying thiolated G4 DNAs onto AuNPs through various methods. However, those constructed with label-free G4 DNAs were found to have a weak enzyme activity due to the G4 destruction on the surface of AuNPs. To address this, here we constructed label-free silicon-based SNAzymes using silica nanoparticles (SiO2) as the core for the first time. We took advantage of the versatility of SiO2 and loaded N-(4-aminobutyl)-N-ethylisoluminol (ABEI) on the surface of silicon spheres (SiO2@ABEI). Then, we found that SiO2@ABEI can achieve high-efficiency adsorption of arbitrary G4 sequences within a few minutes without high requirements for modification methods. In this way, a highly sensitive CL nanoprobe integrated with a catalyst and a chemiluminescence (CL) reagent was successfully constructed. Finally, we use the nanoprobe for the ultrasensitive chemiluminescence detection of acute myocardial infarction (AMI)-related nucleic acids, achieving a detection range of 10 fM–100 pM and an excellent detection limit of 0.8 fM.
危险品化学品经营许可证（带存储）