Silent region barcode particle arrays for ultrasensitive multiplexed SERS detection.

Suspension arrays are a critical components of next generation multiplexed detection technologies. Current fluorescence suspension arrays are limited by a multiplexed coding ceiling and difficulties with ultrasensitive detection. Raman mode is a promising substitute, but the complex spectral peak distributions and extremely weak intrinsic signal intensity severely diminish Raman signal performance in suspension arrays. To address these limitations, we constructed a Raman suspension array system using plasmonic microbeads as barcode substrates and Au nanoflowers as reporter carriers. The well-designed shell morphology and plasmonic microbead composition enabled significant surface enhancement Raman scattering (SERS) such that we were able to adjust silent region Raman-coding intensity levels. Due to synergistic SERS effects from the plasmonic shell and the multi-branched Au nanoflower nanostructure, the reporting signal was greatly improved, enabling ultrasensitive detection of 5-plexed lung cancer markers. Detection in patient serum samples demonstrated good consistency with the standard electrochemiluminescence method. Thus, this silent region SERS barcode-based suspension array is a developmental advance for modern multiplexed biodetection, potentially providing a powerful early disease screening and diagnosis tool.