Versatile low-molecular-weight hydrogelators: achieving multiresponsiveness through a modular design.

Area of Science:

• Materials Science
• Nanotechnology
• Supramolecular Chemistry

Background:

• Developing multiresponsive low-molecular-weight hydrogelators (LMWHs) for smart materials is challenging due to difficulties in predicting molecular assembly and modifying existing LMWHs.
• Existing methods for creating stimuli-responsive hydrogelators are limited by the complexity of introducing new functional groups without compromising gelation properties.

Purpose of the Study:

• To synthesize and characterize novel multi-stimuli responsive LMWHs using a modular design approach.
• To explore the potential of these LMWHs in applications such as controlled drug delivery.

Main Methods:

• A modular design strategy was employed, combining a hydrophobic disulfide-aromatic moiety, a maleimide linker, and a hydrophilic N-acetyl-L-cysteine (NAC) section.
• The synthesized LMWHs were characterized for their response to various stimuli including temperature, pH, reduction/reoxidation, and hydrolysis.

Main Results:

• The LMWHs exhibited reversible gel-to-sol transitions in response to temperature changes.
• The NAC moiety enabled reversible gel control via pH variations.
• Disulfide bond reduction induced a gel-to-sol transition, which could be reversed by reoxidation.
• Hydrolysis of cyclic imide groups provided an additional stimuli-responsive trigger with a suitable timescale for drug delivery.

Conclusions:

• The modular design allows for efficient multi-stimuli responsiveness in LMWHs.
• These novel LMWHs are promising candidates for developing smart nanomaterials, particularly for controlled drug release applications.
• The study suggests a general strategy for incorporating multiple stimuli-sensitive moieties into LMWHs while maintaining the critical hydrophobic-hydrophilic balance.