Ultrasensitive Detection of Cytokines Enabled by Nanoscale ZnO Arrays

Abstract

Early detection of disease markers can provide higher diagnostic power and improve disease prognosis. We demonstrate the use of zinc oxide nanorod (ZnO NR) arrays in a straightforward, reliable, and ultrasensitive detection of the cytokines interleukin-18 and tumor necrosis factor-alpha. Specifically, we exploit the fluorescence-enhancing properties of ZnO NR platforms in cytokine assays involving both a pure buffer and urine. The detection sensitivity achieved using this ZnO NR method is in the subfemtogram per milliliter level, which is 3-4 orders of magnitude more sensitive than conventional assay detection limits. This unparalleled detection sensitivity is achieved without the need for indirect enzyme reactions or specialized instrumentation. We highlight various advantages of using ZnO NR arrays in the ultrasensitive profiling of cytokine levels. Key advantages include robustness of NR arrays, simple and direct assay schemes, high-throughput and multiplexing capabilities, and the ability to correlate directly measured signals to cytokine levels. In conjunction with the extremely high sensitivity demonstrated in this work, our ZnO NR array-based approach may be highly beneficial in early detection of many cytokine-implicated diseases.

Zinc Oxide Nanomaterials for Biomedical Fluorescence Detection

“…8,9,48–56 Specifically, this review will focus on the recent development of one-dimensional (1D) ZnO in fluorescence-based in vitro biodetection. Fluorescence is one of the most widely used detection mechanisms in many fields such as biology, biophysics, biochemistry, genomics, proteomics, drug discovery, disease diagnostics and environmental analysis.…”

Ultrathin and nanostructured ZnO-based films for fluorescence biosensing applications

“…Indeed, zinc oxide (ZnO) is an extremely versatile material even at the nanoscale, due to processing through many synthetic routes [3], easy integration into periodically patterned nanoplatforms [4][5][6], desirable optical properties [7] and stability in typical biomolecular detection environments [8]. Moreover, nanostructured ZnO materials possess high surface area and good biocompatibility and biodegradability [9] that make them very advantageous as platforms to detect the immobilization of glucose [10], cholesterol [11], DNA [5,12] and several other biomolecules [13][14][15][16]. In particular, examples of the use of nanoscale ZnO in the enhanced fluorescence detection of protein interactions have shown that ZnO can act as an excellent signal-intensifying substrate for a wide range of biomolecules [1,17,18].…”

“…Moreover, nanostructured ZnO materials possess high surface area and good biocompatibility and biodegradability [9] that make them very advantageous as platforms to detect the immobilization of glucose [10], cholesterol [11], DNA [5,12] and several other biomolecules [13][14][15][16]. In particular, examples of the use of nanoscale ZnO in the enhanced fluorescence detection of protein interactions have shown that ZnO can act as an excellent signal-intensifying substrate for a wide range of biomolecules [1,17,18]. Recently, the ultra-sensitivity of zinc oxide nanorod arrays in conjunction with a FITC-labeled affinity peptide has been successfully demonstrated for biosensing applications [19].…”

ZnO nanorods-enhanced fluorescence for sensitive microarray detection of cancers in serum without additional reporter-amplification

“…ZnO nanorod, an economical metal oxide, demonstrates strong fluorescence-enhancing ability for neighboring fluorophores due to its intriguing optical properties (Adalsteinsson et al, 2008;Dorfman et al, 2006a,b;Hu et al, 2010a;Kumar et al, 2006). Moreover, unlike on the metallic surfaces, the enhancement is robust without quenching risk even if the fluorophores are directly 0956-5663/$ -see front matter © 2011 Elsevier B.V. All rights reserved.…”