Current advances in aptamer-assisted technologies for detecting bacterial and fungal toxins

Abstract

SummaryInfectious diseases are among the common leading causes of morbidity and mortality worldwide. Associated with the emergence of new infectious diseases, the increasing number of antimicrobial-resistant isolates presents a serious threat to public health and hospitalized patients. A microbial pathogen may elicit several host responses and use a variety of mechanisms to evade host defences. These methods and mechanisms include capsule, lipopolysaccharides or cell wall components, adhesions and toxins. Toxins inhibit phagocytosis, cause septic shock and host cell damages by binding to host surface receptors and invasion. Bacterial and fungal pathogens are able to apply many different toxin-dependent mechanisms to disturb signalling pathways and the structural integrity of host cells for establishing and maintaining infections Initial techniques for analysis of bacterial toxins were based on in vivo or in vitro assessments. There is a permanent demand for appropriate detection methods which are affordable, practical, careful, rapid, sensitive, efficient and economical. Aptamers are DNA or RNA oligonucleotides that are selected by systematic evolution of ligands using exponential enrichment (SELEX) methods and can be applied in diagnostic applications. This review provides an overview of aptamer-based methods as a novel approach for detecting toxins in bacterial and fungal pathogens.

Marine Toxins Detection by Biosensors Based on Aptamers

“…Although aptasensors have been widely used in different fields [102][103][104][105][106][107][108], great efforts still need to be made in the following respects: (1) the optimization of aptamer selection process. Although some aptamers for marine toxins have been selected, it is still not sufficient for a large amount of marine toxins with categories of more than 1000.…”

SELEX-Based Direct Enzyme-Linked Aptamer Assay(DELAA) for Diagnosis of Toxoplasmosis by Detection of SAG1 Antigen in Sera of Mice and Humans

“…The SELEX (systematic evolution of ligands by exponential enrichment) technique was generated by using reiterative in vitro selection for high-a nity and -speci city oligonucleotide ligands (aptamers) against almost any kind of molecules that are of biological or therapeutic interest [35]. Aptamers provide a powerful tool not only used for identi cation of novel diagnostic markers but also for interference with the duplication of the pathogenic agents, and thus have been widely used as biorecognition probes against human pathogens and/or their toxins [36][37][38].…”

Progress on Structured Biosensors for Monitoring Aflatoxin B1 From Biofilms: A Review

“…An aptasensor is a biosensor that uses aptamers as the recognition element. Aptamers are short, single-stranded oligonucleotide sequences (DNA, RNA, or nucleic acid analogs) selected from a nucleic acid molecular library using the in vitro systematic evolution of ligands by exponential enrichment (SELEX) method (Stoltenburg et al, 2007;Abnous et al, 2017b;Alizadeh et al, 2018). Owing to their dimensional folded configurations, aptamers possess a high specificity and affinity for specific targets, including mycotoxins, pathogens, metal ions, pesticides, and cells (Meng et al, 2015;Danesh et al, 2018;Liu et al, 2019;Wu et al, 2019c,d;Yu S.H.…”

“…Generally, a biosensor includes three main parts: a bio-recognition component, a signal converter, and a signal measurement system ( Figure 1A). The bio-recognition element is the core part of a biosensor, and common bio-recognition elements include aptamers (Alizadeh et al, 2018;Danesh et al, 2018), antibodies (Eivazzadeh et al, 2017), molecularly imprinted polymers (MIPs; Ton et al, 2015), and enzymes (Ricard and Buc, 2005). These bio-recognition elements possess a high selectivity and specificity for specific target substances, and only in this way can biological sensors achieve better selectivity.…”