Tuning thermoresponsive supramolecular G-quadruplexes

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Biochemistry

Background:

• Thermoresponsive systems are valuable for fundamental research and applications.
• Polymeric systems dominate, but nonpolymeric alternatives are underexplored.
• Well-defined nonpolymeric supramolecules offer unique advantages.

Purpose of the Study:

• To synthesize and characterize novel 8-aryl-2 -deoxyguanosine derivatives (8ArGs).
• To investigate the self-assembly of 8ArGs into thermoresponsive supramolecular G-quadruplexes (SGQs).
• To explore the modulation of lower critical solution temperature (LCST) in these nonpolymeric systems.

Main Methods:

• Synthesis of three 8-aryl-2 -deoxyguanosine derivatives (8ArGs).
• Isothermal and thermally induced self-assembly studies in aqueous media.
• Characterization of supramolecular G-quadruplexes (SGQs) and higher-order assemblies (supramolecular hacky sacks, SHS).
• Modulation of LCST by intrinsic, extrinsic, and supramolecular parameters.

Main Results:

• Successfully synthesized 8ArGs that self-assemble into thermoresponsive SGQs.
• Demonstrated the formation of higher-order supramolecular hacky sacks (SHS) above the LCST.
• LCST was tunable from 28-59 °C by altering 8ArG structure, salt type, and coassembly.
• Replacing KI with KSCN abolished thermoresponsiveness; cation and pH had minor effects.

Conclusions:

• Developed novel nonpolymeric thermoresponsive supramolecular systems based on 8ArGs.
• These systems offer tunable LCSTs, presenting an alternative to traditional polymers.
• Potential for applications in fundamental studies and biorelevant fields.