Rapid and sensitive SERS detection of the cytokine tumor necrosis factor alpha (tnf-α) in a magnetic bead pull-down assay with purified and highly Raman-active gold nanoparticle clusters
- 120 Downloads
Tumor necrosis factor alpha (TNF-α) is a cytokine with significance in early diagnosis of cardiovascular diseases, obesity and insulin resistance. We demonstrate the proof of concept for a rapid and sensitive detection of TNF-α using a magnetic bead pull-down assay in combination with surface-enhanced Raman scattering (SERS). The use of purified and highly SERS-active small clusters of gold nanoparticles (AuNP) provides the high sensitivity of the assay with a limit of detection of ca. 1 pg/mL. Continuous density gradient centrifugation was employed for separating the very bright silica-encapsulated AuNP dimers and trimers from the significantly weaker AuNP monomers. Negative control experiments with other cytokines (IL-6, IL-8) and bovine serum albumin (BSA) confirm the high specificity of the assay, but indicate also space for future improvements by further reducing non-specific binding between proteins and the SERS nanotags. The multiplexing potential of this SERS-based detection scheme is exemplarily demonstrated by using a set of three spectrally distinct and highly SERS-active AuNP clusters with unique spectral barcodes.
KeywordsSilica encapsulation Gold nanoparticles Surface-enhanced Raman scattering TNF-α Multiplexing
Y.M.L. thanks the China Scholarship Council (CSC) for the financial support of her research visit at the University of Duisburg-Essen. YML also thanks the Fundamental Research Funds from the Central Universities (FRF-TP-15-012A2) for the financial support. SS and YW acknowledge financial support from the German Research Foundation (DFG, WA 3369/1-1).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- 2.Borges MC, Takeuti TD, Terra GA, Ribeiro BM, Rodrigues-Junior V, Crema E. Comparative analysis of immunological profiles in women undergoing conventional and single-port laparoscopic cholecystectoy. Arq Bras Cir Dig. 2016;29(3):164–9. https://doi.org/10.1590/0102-6720201600030009.CrossRefGoogle Scholar
- 4.Saito K, Kobayashi D, Sasaki M, Araake H, Kida T, Yagihashi A, et al. Detection of human serum tumor necrosis factor-alpha in healthy donors, using a highly sensitive immuno-PCR assay. Clin Chem. 1999;45(5):665–9.Google Scholar
- 5.Aydin EB, Aydin M, Sezginturk MK. A highly sensitive immunosensor based on ITO thin films covered by a new semi-conductive conjugated polymer for the determination of TNF alpha in human saliva and serum samples. Biosens Bioelectron. 2017;97:169–76. https://doi.org/10.1016/j.bios.2017.05.056.CrossRefGoogle Scholar
- 26.Willets KA, Van Duyne RP. Localized surface plasmon resonance spectroscopy and sensing. Annu Rev Phys Chem. 2007;58:267–97. https://doi.org/10.1146/annurev.physchem.58.032806.104607.CrossRefGoogle Scholar
- 27.Zhang Y, Li X, Xue B, Kong X, Liu X, Tu L, et al. A facile and general route to synthesize silica-coated SERS tags with the enhanced signal intensity. Sci Rep. 2015;5 https://doi.org/10.1038/srep14934.
- 28.Zhang Y, Walkenfort B, Yoon JH, Schlücker S, Xie W. Gold and silver nanoparticle monomers are non-SERS-active: a negative experimental study with silica-encapsulated Raman-reporter-coated metal colloids. Phys Chem Chem Phys. 2015;17(33):21120–6. https://doi.org/10.1039/c4cp05073h.CrossRefGoogle Scholar