Cascaded strand displacement for non-enzymatic target recycling amplification and label-free electronic detection of microRNA from tumor cells

Catalytic DNA Strand Displacement Cascades Applied to Logic Programming

“…The encoding allows inputs to act as catalysts over implication gates without being depleted. This feature, which is the main contribution here, could increase the sensitivity in applications susceptible to low concentration regimes [28], [29].…”

“…More importantly, this can be done by using the same displacement mechanism, just with the aid of disposable strands that will be exchanged for input molecules on a one-on-one basis. Such a characteristic has played a crucial role in approaches where amplification or signal restoration is needed to maintain the digital abstraction [17]- [19] as well as in applications where an accurate discrimination of low-abundant nucleic acids, such as microRNAs in serum, is desirable [28], [29].…”

Dynamically Programmed Switchable DNA Hydrogels Based on a DNA Circuit Mechanism

“…It is well known that one of the most troublesome defects in DNA circuit systems is leakage causing the generation of the noise signals (nonspecific release of PEG‐GNPs through the cleavage of the CL ) even in the absence of C caused by undesired entropy‐drive DNA displacement reaction between F and CL ( S‐2/S‐3 ) . Before we evaluated the sol–gel phase transitions of the DNA hydrogels in response to C , the amount of F was optimized, such that the use of F × 0.3 (0.3 equivalent of CL : 79 pmol) resulted in satisfactory specific sol–gel phase transitions in response to C (Figure S2, Supporting Information).…”

“…Herein, we describe a new class of biological stimuli‐responsive DNA hydrogels with a dynamically programmed DNA system that relies on entropy‐driven catalytic reactions (so‐called DNA circuit systems) through cascading toehold‐mediated DNA displacement reactions (TMDRs), allowing the catalytic cleavage of cross‐linking points and main chains in response to an appropriate DNA input ( Figure ). The DNA hydrogels were prepared using long dsDNA ([ M1 / M2 ] n ) bearing dangling single stranded DNAs (brawn color), and cross‐linker ( CL ) bearing an overhang (brawn color) at both ends.…”

Target-triggered triple isothermal cascade amplification strategy for ultrasensitive microRNA-21 detection at sub-attomole level

“…3B showed a good linear correlation of the current response difference (ΔI¼I miR-21 -I blank ) to the logarithm of the miR-21concentrations (logC miR-21 ) ranged from 1 aM to 100 pM, with a regression equation of ΔI/μA¼0.6904þ0.0234 logC miR-21 /M (R 2 ¼0.997). This kind of logarithmic relationship between the response signals with the concentration of target biomolecules is widely used for various DNA/miR biosensors Liu et al, 2008;Zhao et al, 2012a;Fan et al, 2014;Shi et al, 2016;Li et al, 2016), immunosensors (Kang et al, 2010) and cytosensors (Zhao et al, 2012b). The main reason for this phenomenon might be due to the intrinsic property of ligandreceptor bio-recognition.…”