Inorganic nanoparticles coupled to nucleic acid enzymes as analytical signal amplification tools

Abstract

Nucleic acid enzymes (NAzymes) are a class of nucleic acid molecules with catalytic activity, which can be modulated by the presence of different species such as metal ions, genetic biomarkers, small molecules or proteins, among others. NAzymes offer several important advantages for development of novel bioanalytical strategies, resulting from their functionality as specific recognition elements and as amplified analytical signal generators, making them ideal candidates for developing highly specific bioanalytical strategies for the detection of a wide variety of targets. When coupled with the exceptional features of inorganic nanoparticles (NPs), the sensitivity of the assays can be significantly improved, allowing the detection of targets using many different detection techniques including visual readout, spectrophotometry, fluorimetry, electrochemiluminescence, voltammetry, and single-particle inductively coupled plasma-mass spectrometry. Here we provide an overview of the fundamentals of novel strategies developed to achieve analytical signal amplification based on the use of NAzymes coupled with inorganic NPs. Some representative examples of such strategies for the highly sensitive detection of different targets will be presented, including metal ions, proteins, DNA- or RNA-based biomarkers, and small molecules or microorganisms. Furthermore, future prospective challenges will be discussed.

MNAzymes and gold nanoparticles as isothermal signal amplification strategy for visual detection of miRNA

“…This allows stringent assay conditions, including temperature and pH of the medium, that are not possible when using protein enzymes [ 12 , 13 ]. Among the different types of DNAzymes that have been described in the literature, those containing a catalytic core with RNA cleavage activity have been widely studied [ 14 – 16 ]. A modification of this type of cleaving DNAzymes has led to a novel structure called multicomponent nucleic acid enzymes (MNAzymes) [ 17 ].…”