Layered double hydroxide-based antioxidant dispersions with high colloidal and functional stability.

Area of Science:

• Materials Science
• Nanotechnology
• Biochemistry

Background:

• Oxidative stress is a major contributor to various diseases.
• Developing stable antioxidant delivery systems is crucial for therapeutic applications.
• Ellagic acid (EA) is a potent antioxidant with limited bioavailability and stability.

Purpose of the Study:

• To design highly stable antioxidant nanoparticles based on ellagic acid (EA) intercalated into MgAl-layered double hydroxide (LDH).
• To optimize the colloidal stability of these nanoparticles through surface functionalization with polyelectrolytes.
• To evaluate the preservation of antioxidant activity in the developed nanocomposite.

Main Methods:

• Ring-opened ellagic acid (EA) was intercalated into MgAl-layered double hydroxide (LDH) nanoparticles.
• Nanoparticle morphology was modified using ethanolic washing to create EtOH-EA-LDH.
• Surface functionalization was performed using positively charged polyelectrolytes: polyethyleneimine (PEI), protamine sulfate (PS), and poly(acrylamide-co-diallyl dimethyl ammonium chloride) (PAAm-co-DADMAC).
• Colloidal stability was assessed by measuring the critical coagulation concentration (CCC) against salt-induced aggregation.
• Antioxidant activity was evaluated through radical scavenging assays.

Main Results:

• Ethanolic washing yielded EtOH-EA-LDH with a high specific surface area.
• Surface adsorption of PEI and PAAm-co-DADMAC provided remarkable colloidal stability, with CCC values exceeding 1 M.
• Polyelectrolyte coating effectively neutralized surface charge and induced overcharging, enhancing stability.
• PS coating resulted in limited colloidal stability compared to PEI and PAAm-co-DADMAC.
• The antioxidant activity of EA was well-preserved in the polyelectrolyte-coated nanocomposite.

Conclusions:

• A highly stable antioxidant nanocomposite was successfully developed using EA intercalated into LDH.
• Surface functionalization with specific polyelectrolytes significantly improves colloidal stability, particularly in high electrolyte concentrations.
• The developed nanocomposite maintains high antioxidant efficacy, offering a promising strategy to combat oxidative stress in challenging environments.