2D Au Nanosphere Arrays/PVA-PBA-Modified-Hydrogel Composite Film for Glucose Detection with Strong Diffraction Intensity and Linear Response

Abstract

A novel glucose sensor was reported that consisted of two-dimensional (2D) Au nanosphere arrays and glucose-responsive hydrogel film. This sensor exhibited an intense diffraction signal and an obvious diffraction color on a quartz slide due to the strong diffraction intensity of the Au nanosphere arrays. Thus, glucose was detected via the variation of diffraction wavelength and diffraction color, without a high reflective mirror. In addition, by introducing poly(vinyl alcohol) (PVA) to crosslink the phenylboronic acid (PBA)-modified hydrogel film, the diffraction wavelength of the 2D Au nanosphere arrays/hydrogel composite film shifted in the same direction in high ionic strength condition. In particular, it showed a nearly linear red-shift when the glucose concentration increased from 0 mM to 20 mM. Moreover, this glucose sensor displayed good reproducibility. The nearly linear response and good reproducibility were highly helpful for improving practical application of this glucose sensor.

Keywords: 2D Au nanosphere arrays; PVA-PBA-modified-hydrogel composite film; diffraction intensity; glucose detection; linear response.

Figure 1

Preparation of the two-dimensional (2D) Au nanosphere arrays/glucose-sensitive hydrogel composite film: (a) 2D polystyrene (PS) colloidal monolayer arrays were fabricated on a clean glass slide by an air/water interfacial self-assembly method; (b) transferring the 2D PS monolayer arrays to a quartz slide; (c) depositing a layer of Au film on the 2D PS colloidal monolayer arrays; (d) annealing at 900 °C for 2 h; (e) pouring reaction solution into the 2D Au nanosphere arrays and subsequently photopolymerizing with UV light; (f) a free-standing 2D Au nanosphere arrays/hydrogel composite film was obtained by peeling it from the substrate; and (g) immersing as-prepared composite film into a poly(vinyl alcohol) PVA aqueous solution to crosslink it with PVA.

Figure 2

Photograph (a) and SEM image (b) of the 2D Au nanosphere arrays (Inset: SEM image of the PS colloidal monolayer arrays template); photograph (c) and SEM image (d) of 2D Au nanosphere arrays/PBA-modified hydrogel composite film; (e) representative diffraction spectra of the 2D Au nanosphere arrays/PBA-modified hydrogel composite films in low ionic strength buffer solution at different glucose concentrations; and (f) glucose concentration dependence of the diffraction wavelength of the composite films (Inset: photographs of 2D Au nanosphere arrays/PBA-modified hydrogel composite films at different glucose concentrations. The scale bar is 0.15 cm). Error bars represent standard deviation (SD) of four samples.

Figure 3

(a) Representative diffraction spectra of 2D Au nanosphere arrays/PBA-modified hydrogel composite films in high ionic strength buffer solution at different glucose concentrations; (b) glucose concentration dependence of the diffraction wavelength of the composite films; and (c) interactions of PBA-modified hydrogel with the furanose form of glucose in high ionic strength buffer solution with increasing glucose concentration. Error bars represent standard deviation (SD) of four samples.

Figure 4

(a) Representative diffraction spectra of 2D Au nanosphere arrays/PVA-PBA-modified hydrogel composite films in high ionic strength buffer solution at different glucose concentrations; (b) glucose concentration dependence of the diffraction wavelength of the composite films (Inset: photographs of 2D Au nanosphere arrays/PVA-PBA-modified hydrogel composite films at different glucose concentrations, the scale bar is 0.15 cm); (c) and interaction of PBA-modified hydrogel with the PVA and interaction of the PVA-PBA-modified hydrogel composite film with glucose in high ionic strength buffer solution. (d) Diffraction peak positions of the 2D Au nanosphere arrays/PVA-PBA-modified hydrogel composite films at the glucose concentration from 0 mM to 20 mM. The line is linear fit. Error bars represent standard deviation (SD) of four samples. (e) Diffraction wavelength of different samples at the glucose concentration of 5 mM.

Figure 5

The reported detected lowest glucose concentration based on photonic crystals (PCs) glucose sensors in the References.