Label-Free Creatinine Optical Sensing Using Molecularly Imprinted Titanium Dioxide-Polycarboxylic Acid Hybrid Thin Films: A Preliminary Study for Urine Sample Analysis

Seung-Woo Lee,Sergiy Korposh,Shigekiyo Matsumoto,Yeawon Park,Sota Matsuzaki,Steve James,Tao Wang,Shinichi Tatsumi,Soad Ahmed

doi:10.3390/chemosensors9070185

Seung-Woo Lee, Sergiy Korposh + Show 7 more

Open Access

https://doi.org/10.3390/chemosensors9070185

Copy DOI

Abstract

Creatinine (CR) is a representative metabolic byproduct of muscles, and its sensitive and selective detection has become critical in the diagnosis of kidney diseases. In this study, poly(acrylic acid) (PAA)-assisted molecularly imprinted (MI) TiO2 nanothin films fabricated via liquid phase deposition (LPD) were employed for CR detection. The molecular recognition properties of the fabricated films were evaluated using fiber optic long period grating (LPG) and quartz crystal microbalance sensors. Imprinting effects were examined compared with nonimprinted (NI) pure TiO2 and PAA-assisted TiO2 films fabricated similarly without a template. In addition, the surface modification of the optical fiber section containing the LPG with a mesoporous base coating of silica nanoparticles, which was conducted before LPD-based TiO2 film deposition, contributed to the improvement of the sensitivity of the MI LPG sensor. The sensitivity and selectivity of LPGs coated with MI films were tested using CR solutions dissolved in different pH waters and artificial urine (near pH 7). The CR binding constants of the MI and NI films, which were calculated from the Benesi–Hildebrand plots of the wavelength shifts of the second LPG band recorded in water at pH 4.6, were estimated to be 67 and 7.8 M−1, respectively, showing an almost ninefold higher sensitivity in the MI film. The mechanism of the interaction between the template and the TiO2 matrix and the film composition was investigated via ultraviolet–visible and attenuated total reflectance Fourier-transform infrared spectroscopy along with X-ray photoelectron spectroscopy analysis. In addition, morphological studies using a scanning electron microscope and atomic force microscope were conducted. The proposed system has the potential for practical use to determine CR levels in urine samples. This LPG-based label-free CR biosensor is innovative and expected to be a new tool to identify complex biomolecules in terms of its easy fabrication and simplicity in methodology.

Highlights

As a metabolic byproduct of muscles, creatinine (CR) is toxic for cells and is transported through the bloodstream and eliminated via renal filtration [1]
We propose a CR detection method using poly(acrylic acid) (PAA)assisted molecularly imprinted (MI) TiO2 thin films
The spectra were recorded in the silica colloidal solution after each deposition of SiO2 NPs on the PDDA layer reached saturation since the change in the Transmission spectra (TS) was more significant when the outermost layer consisted of SiO2 NPs

Summary

Introduction

As a metabolic byproduct of muscles, creatinine (CR) is toxic for cells and is transported through the bloodstream and eliminated via renal filtration [1]. Blood and urine have different CR levels [2]; generally, the glomerular filtration rate has been universally used to diagnose and monitor kidney diseases [3,4]. Using a fast, accessible, cost effective, and accurate method to measure CR concentrations leads to earlier detection and better management of kidney diseases. The label-free analysis is an effective and promising strategy for fast, simple, and convenient detection of small molecules [10]. They retain the highest degree of activity and affinity for the recognition element

Methods

Results

Conclusion