Aptamer-based biosensors for biomedical diagnostics

Abstract

Aptamers are single-stranded nucleic acids that selectively bind to target molecules. Most aptamers are obtained through a combinatorial biology technique called SELEX. Since aptamers can be isolated to bind to almost any molecule of choice, can be readily modified at arbitrary positions and they possess predictable secondary structures, this platform technology shows great promise in biosensor development. Over the past two decades, more than one thousand papers have been published on aptamer-based biosensors. Given this progress, the application of aptamer technology in biomedical diagnosis is still in a quite preliminary stage. Most previous work involves only a few model aptamers to demonstrate the sensing concept with limited biomedical impact. This Critical Review aims to summarize progresses that might enable practical applications of aptamer for biological samples. First, general sensing strategies based on the unique properties of aptamers are summarized. Each strategy can be coupled to various signaling methods. Among these, a few detection methods including fluorescence lifetime, flow cytometry, upconverting nanoparticles, nanoflare technology, magnetic resonance imaging, electronic aptamer-based sensors, and lateral flow devices have been discussed in more detail since they are more likely to work in a complex sample matrix. The current limitations of this field include the lack of high quality aptamers for clinically important targets. In addition, the aptamer technology has to be extensively tested in a clinical sample matrix to establish reliability and accuracy. Future directions are also speculated to overcome these challenges.3

DNAzyme Hybridization, Cleavage, Degradation, and Sensing in Undiluted Human Blood Serum

“…30,31 Serum is readily available in large quantities compared to mammalian cell extracts. The overall chemical composition of serum is comparable to the intracellular environment in terms of ionic strength and protein concentration (Table S1), although the species of metal ions and proteins is quite different.…”

Recent Advances in Electrochemical-Based Sensing Platforms for Aflatoxins Detection

“…The need of animal immunization for antibody production, which often involves the animal suffering, batch to batch variation, and difficulty in labeling of the specific recognition site, decreases the wide utility of antibodies. Finally, due to the requirement of immobilization and extensive washing in antibody-based affinity assays, it is difficult to carry out the homogeneous assays [39]. Therefore, it is highly desirable to seek the alternative ligands or recognition elements as a new platform for biosensing and analytical applications.…”

Development and Applications of Portable Biosensors

“…However, they are costly, have poor chemical and physical stability, require animals for their production, and are limited in options for some analytes. In recent years, alternatives to antibody-based approaches such as enzyme-substrate reactions, 55 molecularly imprinted polymers, 56 aptamers, 57 and antimicrobial peptides 58 have been developed. DNA hybridization assays 59 provide more sensitive, specific, and rapid detection of target nucleic acids when compared to conventional antibody-based assays.…”