tFNA-aptasensor integrating DNA-framework confined affinity recognition and HCR amplification towards accurate profiling of microRNA for COPD analysis

Environmental smog pollution induces chronic obstructive pulmonary disease (COPD), and causes the urgent need of timely, safe and quantitative testing for risk assessment. The miRNA-based bioanalysis offers a non-invasive access to rapid COPD screening, while challenges remain in accurately identifying miRNAs from complex matrices. Herein, a novel bionic aptasensor has been pioneered for meeting the specific and sensitive detection of the miR-155 in serum for COPD diagnosis, integrating tetrahedral framework nucleic acid (tFNA) confined affinity recognition and enzyme-free hybridization chain reaction (HCR) amplification strategy. Precision-designed tFNAs were fabricated and hybridized with FAM-labeled cDNAs, enabling dual-mode recognition mechanism including spatially confined aptamer recognition and bionic molecular sieve size-selective action. Proteins and pre-miRNAs were excluded, and the target microRNA-155 was specifically captured. This triggered a structural switch of tFNAs and activated cDNA-mediated HCR, assembling double-stranded DNA and achieving exponential fluorescence enhancement synergistically produced by SYBR Green I (SGI) and FAM. The optimal limit of detection as 53 fM for miRNA-155 was achieved with laser-induced fluorescence (LIF). Applied to COPD diagnosis, the detections of trace miRNA-155 were satisfactory and the recovery yields were ranged in 96.4 ± 5.2 % ∼106.2 ± 2.1 % ( n  = 3) in the serum of COPD patients. Smoke-exposed model rats were also analyzed, and the miRNA-155 was achieved with a significant concentration up-regulation to light the COPD. It offers a high-performance protocol for meeting the non-invasive rapid screening of COPD, further providing promising technologies for evaluating safety issues of environmentally induced diseases.