Switchable bifunctional stimuli-triggered poly-N-isopropylacrylamide/DNA hydrogels.

Area of Science:

• Polymer Chemistry
• Materials Science
• Biotechnology

Background:

• Poly-N-isopropylacrylamide (pNIPAM) is a well-known thermosensitive polymer.
• Stimuli-responsive hydrogels are crucial for advanced material applications.
• Controlling hydrogel properties via external stimuli like pH and ions is an active research area.

Purpose of the Study:

• To synthesize DNA-tethered pNIPAM copolymer chains.
• To investigate the formation of stimuli-responsive hydrogels using these chains.
• To explore the switchable transitions of the resulting hydrogels.

Main Methods:

• Synthesis of DNA-tethered pNIPAM copolymer chains.
• Induction of crosslinking using pH changes (i-motif structures) or silver ions.
• Characterization of hydrogel formation and transitions.
• Investigation of thermosensitivity and stability of the hydrogel matrices.

Main Results:

• Successfully synthesized DNA-tethered pNIPAM chains.
• Achieved pH-stimulated (at pH 5.2) and Ag(+) ion-stimulated hydrogel formation.
• Demonstrated switchable hydrogel-to-solution transitions by altering pH (5.2 to 7.5) or using cysteamine to remove Ag(+).
• Observed thermosensitive hydrogel-to-solid transitions and enhanced stability of solid matrices.

Conclusions:

• DNA-tethered pNIPAM chains enable the creation of tunable, stimuli-responsive hydrogels.
• The hydrogels exhibit reversible transitions controlled by pH, silver ions, and temperature.
• These materials show potential for applications requiring controlled phase transitions and stability.