Colorimetric Visualization of Glucose at the Submicromole Level in Serum by a Homogenous Silver Nanoprism–Glucose Oxidase System

Abstract

In this study, we design a homogeneous system consisting of Ag nanoprisms and glucose oxidase (GOx) for simple, sensitive, and low-cost colorimetric sensing of glucose in serum. The unmodified Ag nanoprisms and GOx are first mixed with each other. Glucose is then added in the homogeneous mixture. Finally, the nanoplates are etched from triangle to round by H2O2 produced by the enzymatic oxidation, which leads to a more than 120 nm blue shift of the surface plasmon resonance (SPR) absorption band of the Ag nanoplates. This large wavelength shift can be used not only for visual detection (from blue to mauve) of glucose by naked eyes but for reliable and convenient glucose quantification in the range from 2.0 × 10(-7) to 1.0 × 10(-4) M. The detection limit is as low as 2.0 × 10(-7) M, because the used Ag nanoprisms possess (1) highly reactive edges/tips and (2) strongly tip sharpness and aspect ratio dependent SPR absorption. Owing to ultrahigh sensitivity, only 10-20 μL of serum is enough for a one-time determination. The proposed glucose sensor has great potential in the applications of point-of-care diagnostics, especially for third-world countries where high-tech diagnostics aids are inaccessible to the bulk of the population.

Highly sensitive on-site detection of glucose in human urine with naked eye based on enzymatic-like reaction mediated etching of gold nanorods

“…2D). The detection limit was calculated to be 0.1 μM (3σ rule), which is two orders of magnitude lower than other GNRs-based glucose sensors (Liu et al, 2013;Saa et al, 2014) and is almost the lowest among nanoparticle-based glucose sensors (Table S1, Supplementary Information) (Bi et al, 2015;Bo et al, 2013;Jiang et al, 2010;Kong et al, 2014;Luo et al, 2015;Radhakumary and Sreenivasan, 2011;Shen and Xia, 2014;Shiang et al, 2009;Su et al, 2012Su et al, , 2015bXia et al, 2013;Yi et al, 2013;Zayats et al, 2005;Zhao et al, 2015;Zheng et al, 2015). In addition, the small error bar of the data indicates the method has very high stability (Fig.…”

Solution-based nanosensors for in-field detection with the naked eye

“…Triangular silver nanoplates, also called silver nanoprisms, can reshape in the presence of hydrogen peroxide or halides to yield silver nanodisks. 23,62,66 The change in shape from the sharp edges of the triangles to the rounded corners of spherical nanoparticles changes the colour of the solution from blue/purple to red or yellow-coloured depending on the concentration of the analyte (Fig. 2D).…”

“…The hydrogen peroxide generated by the nanoparticles can be used by HRP to generate coloured signals as explained above. GOx and GOx mimics can be used for the detection of glucose in diabetic patients 23 or in enzyme-linked immunoassays for the detection of proteins with antibodies as biorecognition elements. 42,57 Addition of glucose to gold nanoparticles (b) or glucose oxidase (c) generates a red-coloured solution due to reaction of the as-generated gluconic acid with hydroxamine and Fe(III); Bottom: (a) the GOx-like activity of gold nanoparticles generates hydrogen peroxide that is used by HRP to oxidise ABTS 2-(green coloured solution) (reproduced from [74] with permission from the American Chemical Society).…”

“…1D). [23][24][25] A key factor for the development of complex sensing approaches is that these nanomaterials can be decorated with myriads of biomolecules, [26][27][28] polymers 29 and macrocycles 30,31 that confer them specific recognition capabilities for the detection of a wide array of molecules. For example, nanoparticle aggregates linked by peptides can be used for the one-step detection of proteases when the protease activity triggers the dispersion of the nanoparticle collectives.…”

“…1D). [23][24][25] A key factor for the development of complex sensing approaches is that these nanomaterials can be decorated with myriads of biomolecules, [26][27][28] nanoparticles show size-dependent emission properties that cover the whole visible spectrum. 44,45 Nanomaterials have been a true game changer in the field of solution-based sensing due to their easy functionalization, chemical reactivity and outstanding physical properties.…”