Fluorescence resonance energy transfer system coupled with photonic crystals labeling strategy for multiplexed detection of microRNAs from breast cancer

[Display omitted] •PhCs as both labels and carriers enabling synchronous optical detection of miRNAs.•Enzyme-free amplification reactions combined with FRET output signal.•The limits of detection (LOD) for miRNAs all reach fM level.•The sensor can directly detect miRNA in 1 μL untreated human serum sample. MicroRNAs (miRNAs) play a crucial role in post-transcriptional gene expression and freely circulate in the body. Dysregulation of miRNA signaling is associated with various diseases, including breast cancer (BC). The miRNA profiles from liquid biopsies offer a promising strategy for cancer diagnosis, prognosis and monitoring. Particularly, the simultaneous profiling of multiple miRNA levels greatly enhances the accuracy of cancer diagnosis. In this study, photonic crystals (PhCs) serve as both labels and carriers enabling synchronous optical detection of multiple miRNA targets overexpressed in BC. The process is achieved by triggering enzyme-free amplification reactions through target interactions, generating fluorescence resonance energy transfer (FRET). The method offers high sensitivity, sequence specificity, and the capability to detect multiple targets. The limits of detection (LOD) of the sensor for miRNA-21, miRNA-155 and miRNA-10b were 6.36 fM, 8.52 fM and 6.06 fM, respectively. Moreover, the sensor can be directly applied to untreated human serum with a minimal sample volume requirement of only 1 μL. The simultaneous detection of miRNAs in clinical serum samples from healthy individuals and BC patients was carried out. The results show that the average relative expression levels of miRNA-21, miRNA-155 and miRNA-10b in the BC patient group were 12.18 ± 3.20, 17.27 ± 2.17 and 12.17 ± 1.59 times that of the healthy group, respectively. Therefore, the developed multi-detection strategy can precisely identify these cancer biomarkers and offer a crucial pathway for minimally invasive cancer diagnostics, cancer prevention, early intervention and treatment.