The gold-nanoparticle-based surface plasmon resonance light scattering and visual DNA aptasensor for lysozyme

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.

Strategies for enhancing the sensitivity of plasmonic nanosensors

“…Du and co-workers [230] expanded this HRS-based DNA detection approach to a common spectrofluorometer and observed greatly enhanced light scattering from target DNA-directed oligonucleotidefunctionalized AuNPs. A AuNP RLS-based protein assay was reported by Wang and co-workers [241]. A lysozyme-bindingaptamer was first bound to a AuNP surface via electrostatic interaction to stabilize the AuNPs at high ionic strength.…”

Automatic Enumeration of Gold Nanomaterials at the Single-Particle Level

“…In this illustration, the detection of Kanamycin with 20-nm AuNPs were used based on our previous studies. 45 Kanamycin, as an aminoglycoside compound, could induce formation of AuNP aggregates with submicron or larger sizes ( Figure S-4). The single 20-nm AuNP was nearly invisible under the common dark-field microscope, but the aggregates presented bright yellow or red colors (Figure 6 A, B & C).…”

“…45 Thus, the automatic counting method provided a feasible way for signal transduction in AuNP-aggregation detection systems. …”

Biosensors Based on Nanoparticles and Electrochemical Detection

“…This intensity varies when the analyte is attached. 25,26 iii. Mass-sensitive sensors (piezoelectric): They are based on resonance frequency variations.…”