High Sensitivity Au-based Kretschmann Surface Plasmon Resonance Sensor for Urea Detection

Abstract

Kretschmann-based Surface Plasmon Resonance (SPR) optical sensor was applied to detect the presence of kidney wastes such as urea in solutions. To enhance the sensitivity of the SPR sensor, nanolaminated gold film (thickness of 50 nm) was used. In this work, the SPR response to urea in various concentrations were measured and investigated using optical wavelengths of 670 nm and 785 nm. The signals were compared between pure urea solution versus mixed solution in the presence of the 0.227 µmol urease enzyme. The proposed mixed solution is to eliminate doping and gel entrapment process for enzyme immobilization in conventional method. Angular interrogation technique was used to measure the sensor performance in urea detection using pure and mixed solutions with urea concentration of 0-800 mM. Upon exposure to mixed solution using 785 nm optical wavelength, the nanolaminated gold film exhibited higher SPR sensitivity as much as 7.8 M-1 than a pure urea solution (1.4 M-1). The coupling activity between urea and urease molecules in the mixed solution near the nanolaminated gold film surface lead to sensitivity enhancement. Angle shifting of mixed solution on 50 nm-thick nanolaminated gold film using 670 nm optical wavelength was greater by ~50% compared to 785 nm. Sensorgram data shows a steady and linear increment in SPR incident angle shifting when urea concentration increased. To the best of our knowledge, this is the first time that Kretschmann-based SPR has been used for urea sensing at 670 nm and 785 nm optical wavelengths.

Sweat analysis for urea sensing: trends and challenges

“…If the surface has a brous morphology, it indicates the presence of urea on urease; (ii) to quantify urea concentration, the cyclic voltammograms of the modied electrodes are observed in the presence of urea and the increase in current is quantied. 82 Similarly, Branzoi et al fabricated an amperometric biosensor using nanostructure polypyrrole (Ppy) and polyortho-phenylenediamine (POPDA), whose morphology is affected by the pH change correlating with increasing urea concentrationsthe morphological modications are observed using SEM. 70 Although the results obtained in these experiments are accurate and the electrodes are highly sensitive, these arrangements require bulky, expensive instruments that are labour-intensive and necessitate expert personnel for sample preparation, etc.…”

“…If the surface has a fibrous morphology, it indicates the presence of urea on urease; (ii) to quantify urea concentration, the cyclic voltammograms of the modified electrodes are observed in the presence of urea and the increase in current is quantified. 82 Similarly, Branzoi et al fabricated an amperometric biosensor using nanostructure polypyrrole (Ppy) and polyortho-phenylenediamine (POPDA), whose morphology is affected by the pH change correlating with increasing urea concentrations – the morphological modifications are observed using SEM. 70…”

“…Although SPR is a susceptible, label-free method for analysis, it is instrument intensive, doesn't support continuous monitoring, and is yet to be designed into a skin-interfaced platform. 82 6.3.4 Spectroscopy. Spectroscopy is a novel optical technique that has recently been extensively used in research due to its sensitivity to almost all biomarkers and analytes.…”

Characterisation of nano-thin film GO/TiO2 layers for Kretschmann-based surface plasmon resonance visible sensing using FDTD method

“…Therefore, the Kretschmann configuration is the best method to apply for plasmon excitation. The biomolecular interaction can be determined by measuring the SPR resonant angle shift during sensing [1,2]. The sensitivity of the SPR sensor can be improved by using nanoparticles in the nano-thin film.…”

Multi-response optimization of chromium/gold-based nanofilm Kretschmann-based surface plasmon resonance glucose sensor using finite-difference time-domain and Taguchi method

“…Nowadays, surface plasmon resonance (SPR)-based sensors are receiving profound attention for its fast response and high accuracy to measure biomolecular interaction in real time and label-free environment. [1][2][3][4] Even in the ongoing COVID-19 pandemic, SPR-based biosensors have emerged as a promising and alternative solution for the diagnosis of the lethal virus. 5 The inclusion of localized SPR and metamaterial effects are also popular sensing alternatives.…”