Dual-digital encoded suspension array based on Raman spectroscopy and laser induced breakdown spectroscopy for multiplexed biodetection

Aiming to satisfy the growing requirements of high-throughput multiplexed bioassays, a dual-digital encoded suspension array (SA) analysis based on Raman spectroscopy and laser induced breakdown spectroscopy (LIBS) is proposed. The SAs are prepared by the core-shell microbeads with Raman reporter molecules doped inside and elementary encoded nanoparticles (EENPs) assembled on the surface. Raman scattering spectra and LIBS spectra are obtained after excitation by laser, the specific peaks from the spectra are used for decoding. Highly sensitive and selective recognition of dual-digital encoded SA are realized by immunoassay experiments with a detection limit of 9.17 pM. Owing to the narrow bandwidths and unchangeable read-out wavelengths, the above two types of spectra provide high accuracy and stability for encoding. Meanwhile, Raman and LIBS spectra are independent from fluorescence, thus the cross talk between the encoding signal and fluorescent label on analytes can be avoided. Moreover, since the coding number grows exponentially along with the increase of types of encoding materials, the combination of two channels promote a considerable rise in detection throughput. All the above properties demonstrate the unique potential of dual-digital encoded SA in high-throughput biological detection.