Photo-induced multiple charge transfer resonance of Ce-MOF for SERS detection of nucleic acid

Background: Sensitive and accurate detection of important cancer markers MicroRNAs (miRNAs) is critical to prevent and treat disease. Among many detection techniques, surface-enhanced Raman scattering(SERS) has attracted much attention due to its advantages such as narrow spectral peak, low interference and non-destructive detection. Interestingly, non-noble metal SERS substrates show good prospects due to their outstanding spectral reproducibility and biocompatibility. However, the low SERS sensitivity of non-noble metal substrates also limited their detection performance. Therefore, it is crucial to design a non-noble metal substrate with high SERS sensitivity for nucleic acid detection.

Results: In this study, we found that the photo induction (30 min) of Ce-MOF has high SERS performance (abbreviated as Ce-MOF₃₀). It is due to that photo-induction can regulate the energy level of the Ce-MOF and break the benzene-C bonds to introduce a defect energy level, which provides additional charge transfer channels. The Ce-MOF₃₀ substrates can achieve an enhancement factor (EF) of 6.71 × 10⁶ for Methylene blue (MB), about 7-fold higher than pristine Ce-MOF, which is the best Ce-based SERS substrate so far. Finally, a SERS detection platform was fabricated by combining the Mg²⁺ assisted dual signal amplification for miRNA 141 assay, and the detection limit was 1.72 fM.

Significance: This work proposed a simple photo-induction strategy to enhance SERS performance, which supplied a new detection platform for detection of nucleic acid and further expand the application of non-noble metal substrate in SERS field.