Surface-enhanced Raman Spectroscopy Detection Research Based On MXene/MoS₂ @AuNPs Composite Structure

There are many kinds of biomolecules,such as protein,glucose,lipids,vitamins and so on.Abnormal expression levels of these biomolecules in the body are signals sent by certain diseases in the body.Generally speaking,the expression level of micro RNAs largely reflects the progression of cancer,and this correlation has gradually attracted widespread attention because of its early trace prediction accuracy.Surface enhanced Raman spectroscopy（SERS）,as a powerful tool for trace sensitive analysis,provides a competitive choice for the sensitive prediction of cancer-related miRNAs.In this work,a synergistic calibrated SERS strategy based on transition metal carbide（MXene）/molybdenum disulfide（MoS₂）@Au Nanoparticles（Au NPs）with controllable morphology（particle size and particle gap）is suggested for the ultrasensitive detection of miRNA-182 by selecting the average intensity of its three own characteristic Raman peaks(at382 cm^-1 and 402 cm^-1 corresponding to MoS₂ and at 611 cm^-1 corresponding to MXene)as a benchmark instead of additional beacon molecules.The linear fitting parameters（R²）for this strategy is available up to 0.9992,which is significantly higher than that of single or double peak calibrated case and thus improve the detection accuracy dramatically.Meanwhile,vertical MoS₂ nanosheets anchored on layered MXene can provide uniformly ordered sites for accommodating suitable-sized Au NPs as“hot spots”with controllable particle gap of 2.2 nm,resulting in the maximum amplified SERS signal at 1362 cm^-1 generated by hairpin probe DNA with Cyanine 5（Cy5）.Based on the above two factors,a linear detection window from 10 a M to 1 n M with an ultralow detection limit of 6.61 a M for miRNA-182 was achieved.