SERS-based Immunoassay in a Microfluidic System for the Multiplexed Recognition of Interleukins from Blood Plasma: Towards Picogram Detection

Abstract

SERS-active nanostructures incorporated into a microfluidic device have been developed for rapid and multiplex monitoring of selected Type 1 cytokine (interleukins: IL-6, IL-8, IL-18) levels in blood plasma. Multiple analyses have been performed by using nanoparticles, each coated with different Raman reporter molecules: 5,5′-dithio-bis(2-nitro-benzoic acid) (DTNB), fuchsin (FC), and p-mercatpobenzoic acid (p-MBA) and with specific antibodies. The multivariate statistical method, principal component analysis (PCA), was applied for segregation of three different antigen-antibody complexes encoded by three Raman reporters (FC, p-MBA, and DTNB) during simultaneous multiplexed detection approach. To the best of our knowledge, we have also presented, for the first time, a possibility for multiplexed quantification of three interleukins: IL-6, IL-8, and IL-18 in blood plasma samples using SERS technique. Our method improves the detection limit in comparison to standard ELISA methods. The low detection limits were estimated to be 2.3 pg·ml−1, 6.5 pg·ml−1, and 4.2 pg·ml−1 in a parallel approach, and 3.8 pg·ml−1, 7.5 pg·ml−1, and 5.2 pg·ml−1 in a simultaneous multiplexed method for IL-6, IL-8, and IL-18, respectively. This demonstrated the sensitivity and reproducibility desirable for analytical examinations.

Analysis of Biomolecules Based on the Surface Enhanced Raman Spectroscopy

“…Immunoassay-based strategy was also applicable to cytokines detection. Kamińska et al [ 45 ] developed an immunoassay-based strategy employing diatom biosilica as the SERS-active substrate and DTNB-labeled immune-AuNPs as the SERS nanotag to detect the interleukin 8 (IL-8) in blood plasma [ 46 ]. Based on this method, a SERS immunoassay combined with a microfluidic device was developed for multiplexed recognition of interleukins IL-6, IL-8, and IL-18 in blood plasma with the LOD of 4.2 pg/mL.…”

Multiplex micro-SERS imaging of cancer-related markers in cells and tissues using poly(allylamine)-coated Au@Ag nanoprobes

“…Therefore, the SERS intensity is also indirectly related to the quantity of the targeted molecules in each pixel of the image. Fast and sensitive indirect imaging of biologically important molecular systems using SERS nanoprobes has been carried out in various kinds of samples [5][6][7][8][9][10][11] and has been implemented in cancer imaging and phenotyping for both cells and tissues [12][13][14][15][16][17][18][19]. In this context, evaluating the expression level of cancer-related cellular membrane receptors is commonly denoted as "immuno-SERS" or "iSERS," by analogy with immunohistochemistry (indirect local detection using dyes) and immunofluorescence (indirect local detection using fluorescent tags) [20][21][22].…”

Photovoltaic cells as a highly efficient system for biomedical and electrochemical surface-enhanced Raman spectroscopy analysis

“…A remarkable variety of techniquessuch as electrochemical methods, 23 nanosphere lithography, 24 electronbeam lithography, 25 nanoimprinting lithography, 26 vapor layer deposition, 27 colloidal suspension, 6 and many other methodsare currently utilized for the fabrication of well-ordered SERS nanostructures. [28][29][30][31][32][33] Generally, SERS-active nanostructures include: (i) colloidal metal nanoparticles, and (ii) solid supportbased substrates. Colloid-based substrates are easy to fabricate and exhibit high SERS enhancement efficiency.…”