Triplex DNA logic gate based upon switching on/off their structure by Ag(+)/cysteine.

Area of Science:

• Biochemistry
• Molecular Biology
• Nanotechnology

Background:

• Intramolecular triplex DNA formation is a key process in DNA nanotechnology.
• The fluorescence of specific oligonucleotides can be modulated by external agents.
• Developing sensitive and reversible biosensors is crucial for various analytical applications.

Purpose of the Study:

• To develop novel sensors for detecting silver ions (Ag+) and cysteine (Cys) based on fluorescence modulation.
• To investigate the reversible nature of the fluorescence response.
• To construct a DNA logic gate utilizing Ag+ and Cys as inputs.

Main Methods:

• Design and synthesis of specific oligonucleotide sequences (Oligo 1 and Oligo 2).
• Utilizing the fluorescence quenching/unquenching mechanism regulated by Ag+ and Cys.
• Characterization of sensor performance, including linear range and detection limits.
• Construction and testing of a DNA logic gate based on fluorescence output.

Main Results:

• Development of a sensor for Ag+ with a linear range of 2.5 nM-40 nM and a detection limit of 1.8 nM.
• Development of a sensor for Cys with a linear range of 10.0 nM-120.0 nM and a detection limit of 8.2 nM.
• Demonstration of reversible fluorescence changes upon alternate addition of Ag+ and Cys.
• Successful construction of a simple DNA logic gate with fast response and good reversibility.

Conclusions:

• The developed oligonucleotide-based sensors offer sensitive and selective detection of Ag+ and Cys.
• The reversible fluorescence modulation enables the creation of dynamic DNA-based logic systems.
• This work presents a promising platform for developing advanced molecular sensors and logic devices.