[Show abstract][Hide abstract] ABSTRACT: We developed a new simple and sensitive assay for lysozyme based on gold nanoparticle plasmon resonance light scattering (PRLS) measurement and naked-eye detection using for the first time the lysozyme DNA aptamer as the recognition element. Lysozyme DNA aptamer could stabilize gold nanoparticles (AuNPs) at high ionic strength. Introducing lysozyme to the system easily triggered the aggregation of AuNPs, producing a red-to-blue color change of the solution, red-shifted plasmon absorption, and enhanced plasmon resonance light scattering. The linear range was found to be 0.2∼4 nM for 0.7 nM AuNPs, 0.3∼6 nM for 1.4 nM AuNPs and 0.6∼8 nM for 2.1 nM AuNPs. About 0.1 nM lysozyme can produce an observable enhancement of PRLS signal. For visual detection, 1 nM lysozyme can produce a very distinctive color change. Satisfactory recoveries were obtained for simulated saliva and diluted urine samples, indicating that the method has potential for analyses of clinical samples. The simplicity and high sensitivity that are consistent with the resources and needs of many laboratories makes this method a good choice for routine analysis.
Schematic description and demonstration of aggregation of DNA aptamer stabalized AuNPs for colorimetric and PRLS sensing of lysozyme.
No preview · Article · Apr 2011 · Analytical and Bioanalytical Chemistry
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to establish a simple and sensitive analytical method for lysozyme using Plasmon Resonance Light-Scattering (PRLS) technique with Gold Nanoparticles (AuNPs) as the probe. Nanomolar level of lysozyme induced AuNPs aggregation with enhanced PRLS. For 1.4 nM citrate-capped AuNPs (13 nm in diameter), the linear range of the calibration curve was 15-50 nM with a detection limit of 13.1 nM for lysozyme. Six nanomolar lysozyme can produce an observable PRLS enhancement. Most potential interfering substances present in urine had a negligible effect on the determination. The interference from human serum albumin in the urinary sample can be reduced by precipitating the albumin with ethanol at pH 4.8-4.9. The 90.1-118.2% recovery was achieved for 8 individual lysozyme-spiked urinary samples. This simple and sensitive method for lysozyme does not require sample clean-up and AuNPs modification, thus provided an alternative for urinary lysozyme determination.