Thrombin-Binding Aptamer with Inversion of Polarity Sites (IPS): Effect on DNAzyme Activity and Anticoagulant Properties

The Recent Progress in DNAzymes-Based Aptasensors for Thrombin Detection

Thrombin (TB) is classified among human blood coagulation proteins with key functions in hemostasis of blood vessels, wound healing, atherosclerosis, tissue adhesion, etc. Moreover, TB is involved as the main enzyme in the conversion of the fibrinogen to fibrin. Given the importance of TB detection in the clinical area, the development of innovative methods can considerably improve TB detection. Newly, aptasensors or aptamer-based biosensors have received special attention for sensitive and facile TB detection. In addition, the aptamer/nanomaterial conjugates have presented new prospects in accurate TB detection as nanoaptasensors. DNA-based enzymes or DNAzymes, as new biocatalysts, have many advantages over protein enzymes and can be used in analytical tools. This article reviews a brief overview of significant progresses regarding the various types of DNAzymes-based aptasensors and nano aptasensors developed for thrombin detection. In the following, challenges and prospects of TB detection by DNAzymes-based aptasensors are discussed.

Beyond G-Quadruplexes-The Effect of Junction with Additional Structural Motifs on Aptamers Properties

G-quadruplexes constitute an important type of nucleic acid structure, which can be found in living cells and applied by cell machinery as pivotal regulatory elements. Importantly, robust development of SELEX technology and modern, nucleic acid-based therapeutic strategies targeted towards various molecules have also revealed a large group of potent aptamers whose structures are grounded in G-quadruplexes. In this review, we analyze further extension of tetraplexes by additional structural elements and investigate whether G-quadruplex junctions with duplex, hairpin, triplex, or second G-quadruplex motifs are favorable for aptamers stability and biological activity. Furthermore, we indicate the specific and pivotal role of the G-quadruplex domain and the additional structural elements in interactions with target molecules. Finally, we consider the potency of G-quadruplex junctions in future applications and indicate the emerging research area that is still waiting for development to obtain highly specific and effective nucleic acid-based molecular tools.