Recent Advances in Aptamer Sensors

Abstract

Recently, aptamers have attracted attention in the biosensing field as signal recognition elements because of their high binding affinity toward specific targets such as proteins, cells, small molecules, and even metal ions, antibodies for which are difficult to obtain. Aptamers are single oligonucleotides generated by in vitro selection mechanisms via the systematic evolution of ligand exponential enrichment (SELEX) process. In addition to their high binding affinity, aptamers can be easily functionalized and engineered, providing several signaling modes such as colorimetric, fluorometric, and electrochemical, in what are known as aptasensors. In this review, recent advances in aptasensors as powerful biosensor probes that could be used in different fields, including environmental monitoring, clinical diagnosis, and drug monitoring, are described. Advances in aptamer-based colorimetric, fluorometric, and electrochemical aptasensing with their advantages and disadvantages are summarized and critically discussed. Additionally, future prospects are pointed out to facilitate the development of aptasensor technology for different targets.

Biosensors to Monitor Cell Activity in 3D Hydrogel-Based Tissue Models

“…Indeed, aptamers offer a better thermal and chemical stability, as well as a more stable sensibility over environmental perturbations, if compared to Abs-based sensors [251]. Moreover, they are characterized by a simpler molecular structure than Abs which can be easily modified with functional groups [252,253] and designed into beacons, which directly emit optical or electrical signaling once the targeted analyte is bound, without the need for further labeling or washing steps [247,249,[254][255][256][257].…”

Aptamer‐based biosensors and application in tumor theranostics

“…According to the signal conversion elements of different types of aptasensors, biological information is usually converted to fluorescent signals, electrochemical signals or color changes, 27‐29 which can be divided into fluorescence, electrochemistry, and colorimetric aptasensors 8‐10 . These changed signals are read by simple instruments, and the result can be visualized.…”

“…Most of the biological recognition elements are macromolecules such as antibodies, aptamers, and enzymes, which have the characteristics of specifically recognizing target analytes to facilitate quantitative or semi-quantitative analysis of a certain target by biosensors. 7 At present, the recognition element of the most applicable aptasensor is a short oligonucleotide chain separated from a random library in vitro by SELEX, 8,9 using different screening strategies and manipulation of the selection conditions to closely control the aptamer-target binding affinity and specificity. 10 Generally, the size of the aptamer sequence can be ~30-70 nucleotides in average length, folded into a three-dimensional structure, and connected to specific biological elements through specificity and affinity, such as metal ions, tumor marker proteins, small molecules, or even viruses, circulating tumor cells, etc.…”

An Electrochemical Ti3C2Tx Aptasensor for Sensitive and Label-Free Detection of Marine Biological Toxins

“…Aptamer, a single-standard oligonucleotide is an ideal candidate. Aptamer is prepared by a technique called systematic evolution of ligand exponential enrichment (SELEX) and has specific binding to the target molecules [ 18 ]. Typically, aptamer has decisive advantages compared to antibodies, such as low cost, high selectivity, high stability, and easy synthesis and functionalization [ 19 ].…”