Ultrasensitive SERS immunoassay based on diatom biosilica for detection of interleukins in blood plasma

• Published in: Analytical and bioanalytical chemistry 2017-11, Vol.409 (27), p.6337-6347
• Main Authors: Kamińska, Agnieszka, Sprynskyy, Myroslav, Winkler, Katarzyna, Szymborski, Tomasz
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Antibodies; Antigens; Biochemistry; Biomarkers; Biosensing Techniques - methods; Blood; Blood plasma; Body fluids; Characterization and Evaluation of Materials; Chemical properties; Chemistry; Chemistry and Materials Science; Cytokines; Diatoms - chemistry; Diatoms - ultrastructure; Enzyme-linked immunosorbent assay; Food Science; Gold; Gold - chemistry; Humans; Immunoassay; Immunoassay - methods; Interleukin 8; Interleukin-8 - blood; Interleukins; Laboratory Medicine; Limit of Detection; Measurement; Metal Nanoparticles - chemistry; Metal Nanoparticles - ultrastructure; Methods; Monitoring/Environmental Analysis; Nanoparticles; Nitrobenzoic acid; Plankton; Plasmas (physics); Raman spectra; Raman spectroscopy; Reproducibility of Results; Research Paper; Silicon Dioxide - chemistry; Spectrum Analysis, Raman - methods; Tags
• ISSN: 1618-2642; 1618-2650
• DOI: 10.1007/s00216-017-0566-5

An ultrasensitive surface-enhanced Raman scattering (SERS) immunoassay based on diatom biosilica with integrated gold nanoparticles (AuNPs) for the detection of interleukin 8 (IL-8) in blood plasma has been developed. The SERS sensing originates from unique features of the diatom frustules, which are capable of enhancing the localized surface-plasmon resonance of metal nanostructures. The SERS immune tags ware fabricated by functionalizing 70-nm Au nanoparticles with DTNB (i.e., 5,5′-dithiobis(2-nitrobenzoic acid)), which acted as a Raman reporter molecule, as well as the specific antibodies. These DTNB-labeled immune-AuNPs can form a sandwich structure with IL-8 antigens (infection marker) and the antibodies immobilized on the biosilica material. Our method showed an improved IL-8 detection limit in comparison to standard ELISA methods. The current detection limit for IL-8 using a conventional ELISA test is about 15.6 pg mL −1 . The lower detection limit for IL-8 in blood plasma was estimated to be 6.2 pg mL −1 . To the best of our knowledge, this is the first report on the recognition of IL-8 in human samples using a SERS-based method. This method clearly possesses high sensitivity to clinically relevant interleukin concentrations in body fluids. The average relative standard deviation of this method is less than 8%, which is sufficient for analytical analysis and comparable to those of classical ELISA methods. This SERS immunoassay also exhibits high biological specificity for the detection of IL-8 antigens. The established SERS immunoassay offers a valuable platform for the ultrasensitive and highly specific detection of immune biomarkers in a clinical setting for medical diagnostics. Graphical Abstract The SERS-based immunoassay based on naturally generated photonic biosilica for the detection of interleukin 8 (IL-8) in human plasma samples