Simple pH-Triggered Control over Hydrogel Formation by Acetyl Valine.

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Biomaterials Engineering

Background:

• Hydrogel formation often requires precise pH control, which can be challenging with traditional modifiers.
• Amino acid derivatives are known to form self-assembled hydrogels, but their gelation kinetics and properties depend on environmental factors like pH.

Purpose of the Study:

• To evaluate acetyl-L-valine (Ac-Val) as a novel, water-soluble pH modifier for inducing hydrogel formation.
• To compare the efficacy of Ac-Val with lactic acid (LA) in modifying pH for gelation.
• To demonstrate the broad applicability of Ac-Val in creating hydrogels with tunable properties.

Main Methods:

• Ac-Val and lactic acid solutions were prepared and used to induce gelation in three amino acid derivatives: Boc-Dopa(Bn)2-OH, Lau-Dopa(Bn)2-OH, and Pal-Phe-OH.
• The pH modification and subsequent hydrogel formation were monitored.
• The properties of the resulting hydrogels (transparency, robustness, elasticity) were assessed.

Main Results:

• Ac-Val proved to be a fully water-soluble and effective pH modifier, allowing for precise control over stock solution preparation and final material pH.
• Compared to inorganic acids, Ac-Val enabled more controlled pH variations.
• Ac-Val induced instantaneous pH modification, allowing precise adjustment before gel network formation.
• Hydrogels formed using Ac-Val exhibited varying properties, with Pal-Phe-OH acting as a supergelator.

Conclusions:

• Ac-Val is a reliable and precise pH modifier for inducing hydrogel formation from amino acid derivatives.
• The Ac-Val method offers advantages in solubility, control, and tunability, making it suitable for creating hydrogels with specific properties.
• This pH-change approach with Ac-Val has broad applicability, particularly for drug delivery systems requiring tailored acidic environments.