The sulfated polysaccharide from a marine red microalga as a platform for the incorporation of zinc ions

• Porphyridium sp. polysaccharide (PS) is a suitable platform for metal incorporation.
• Polysaccharide and Zn-PS solutions were characterized by SAXS and rheology.
• Antibacterial activity of Zn-PS solutions is more potent than the native PS.
• Synergy between Zn2+ and the PS yields a promising applications platform.

The cell-wall sulfated polysaccharide of the marine red microalga Porphyridium sp. is a high molecular weight biopolymer that has potential for use as a platform for metal complexation for various applications. This paper describes the structural and rheological characterization and antibacterial activity of the polysaccharide in combination with Zn2+ (Zn-PS). SAXS and rheology studies indicate that with the addition of ZnCl2 to the sulfated polysaccharide the only change was the increase in viscosity in the entangled regime. The antibacterial activity of Zn-PS solutions was more potent than that of the native polysaccharide against Gram-negative and Gram-positive bacteria. The synergy between the bioactivities of Zn2+ (which is a key player in wound healing and is active against variety of pathogens) and the unique bioactivities of the polysaccharide (e.g., anti-inflammatory) indicates promising potential for the development of novel products for the pharmaceutical and cosmetics industries.