Highly Sensitive and Selective Colorimetric Detection of Creatinine Based on Synergistic Effect of PEG/Hg2+-AuNPs.

Xia Xia,Li Li,Liu Liu,Zhu Zhu,Bian Bian

doi:10.3390/nano9101424

Abstract

A colorimetric sensor, based on the synergistic coordination effect on a gold nanoparticle (AuNP) platform has been developed for the determination of creatinine. The sensor selects citrate stabilized AuNPs as a platform, polyethylene glycol (PEG) as a decorator, and Hg2+ as a linkage to form a colorimetric probe system (PEG/Hg2−–AuNPs). By forming hydrogen bond between the oxygen-containing functional groups of PEG and citrate ions on the surface of AuNPs, this probe shows good stability. PEG coordinated with Hg2+ synergistically and specifically on the surface of dispersed AuNPs, and the existence of creatinine could induce the aggregation of AuNPs with a corresponding color change and an obvious absorption peak shift within 5 min. This PEG/Hg2+–AuNPs probe towards creatinine shows high sensitivity, and a good linear relationship (R2 = 0.9948) was obtained between A620–522 nm and creatinine concentration, which can achieve the quantitative calculations of creatinine. The limit of detection (LOD) of this PEG/Hg2+–AuNPs probe was estimated to be 9.68 nM, lower than that of many other reported methods. Importantly, the sensitive probe can be successfully applied in a urine simulating fluid sample and a bovine serum sample. The unique synergistic coordination sensing mechanism applied in the designation of this probe further improves its high selectivity and specificity for the detection of creatinine. Thus, the proposed probe may give new inspirations for colorimetric detection of creatinine and other biomolecules.

Highlights

Creatinine (2-imino-1-methyl-2-imidazoline-4-ketone) is an important clinical analyte that is produced through muscle metabolism and removed by glomerular filtration
After the addition of polyethylene glycol (PEG) and Hg2+ or PEG and creatinine into AuNPs, the color and absorption wavelength of mixture remained unchanged as shown in Figure 1A and Figure 1B
We deduced that the above changes could be attributed to the synergistic coordination effect among PEG, Hg2+, and creatinine on the platform of citrate capped AuNPs

Summary

Introduction

Creatinine (2-imino-1-methyl-2-imidazoline-4-ketone) is an important clinical analyte that is produced through muscle metabolism and removed by glomerular filtration. The physiological creatinine level of a healthy person is about 3.5 to 34.6 mM in urine and 50 to 140 μM in blood [1]. The deviation of the normal physiological creatinine level in urine or human blood within a long period of time indicates the dysfunction of human body, such as kidney problems or muscular disorders mostly. Kidney disease, which is of great concern all over the world, is so widespread that a number of people suffer from renal damage greatly every year [2]. The concentration of creatinine in human blood or urine is a vital marker for early assessment of renal function and muscle damage clinically [3,4]. A practical and sensitive method for qualitative identification and quantitative calculations of creatinine is needed urgently

Methods

Results

Conclusion