# Gelatin-Based Zinc-Loaded Hydrogels Constructed with the Assistance of Sodium Alginate and Zinc Sulfate Solution Soaking Method

## TL;DR

This paper describes a method to create zinc-loaded hydrogels using gelatin, sodium alginate, and zinc sulfate, which could be useful for controlled zinc delivery.

## Contribution

A novel zinc-loading method using gelatin, sodium alginate, and ZnSO4 soaking is introduced, enhancing zinc capacity and pH sensitivity.

## Key findings

- Hydrogels with a 7:3 gelatin-to-sodium alginate ratio achieved a zinc loading of 52 mg/g at 25 wt% ZnSO4.
- Sodium alginate improved pH sensitivity and zinc loading capacity of the hydrogels.
- Zinc sulfate strengthened hydrogel structure via hydrophobic interactions and hydrogen bonds.

## Abstract

Constructing a zinc delivery system is crucial for scientific zinc supplementation. In this study, gelatin-based zinc-loaded hydrogels were constructed with the assistance of sodium alginate and a ZnSO4 solution soaking method. The zinc loading capacity, texture properties, rheological properties, microstructure, and pH sensitivity of hydrogels under different ratios of gelatin to sodium alginate were investigated. Results showed that the loading of zinc by hydrogel was successfully achieved through a ZnSO4 solution soaking method, and increasing the ZnSO4 concentration was conducive to zinc loading and hydrogel structure strengthening. Adding sodium alginate further enhanced the zinc loading capacity of hydrogel. When the concentration of ZnSO4 was 25 wt%, the zinc loading of hydrogel containing only gelatin and hydrogel with a 7:3 ratio of gelatin to sodium alginate was 29 mg/g and 52 mg/g, respectively. In addition, sodium alginate also endowed the hydrogel with a certain pH sensitivity. When the ratio of gelatin to sodium alginate was 7:3, the hydrogel showed obvious pH response behavior. Spectroscopy results revealed that zinc sulfate strengthened the hydrogel structure by inducing hydrophobic interactions and the formation of hydrogen bonds, while Zn2+ was bound to oxygen atoms through coordination bonds in hydrogel. These results could provide new ideas for the construction of zinc-loaded hydrogels.