High-loading hyaluronic acid hydrogel beads via reverse spherification based on Ca2+-hyaluronic acid interaction

Authors: YU, ZHE - Jiangnan University; LI, HANG - Jiangnan University; Chiou, Bor Sen; LIU, FEI - Jiangnan University

Submitted to: International Journal of Biological Macromolecules
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/26/2025
Publication Date: 11/27/2025
Citation: Yu, Z., Li, H., Chiou, B., Liu, F. 2025. High-loading hyaluronic acid hydrogel beads via reverse spherification based on Ca2+-hyaluronic acid interaction. International Journal of Biological Macromolecules. 337. Article 149304. https://doi.org/10.1016/j.ijbiomac.2025.149304.
DOI: https://doi.org/10.1016/j.ijbiomac.2025.149304

Interpretive Summary: Oral supplementation of hyaluronic acid has been shown to reduce skin dryness and wrinkles as well as improve joint functions. Currently, hyaluronic acid is ingested orally as a liquid. One way to expand its use for controlled release applications is through encapsulation. In this study, calcium alginate was used to encapsulate hyaluronic acid by reverse spherification. Reverse spherification was optimized to reduce the high viscosity of the hyaluronic acid solution and enable spherical beads to be formed during encapsulation. The resulting encapsulated beads had a high hyaluronic acid loading and membranes with a high rupture force. These results indicated that hyaluronic acid can be successfully encapsulated for potentially new controlled release applications.

Technical Abstract: Calcium alginate hydrogel beads have become popular nutrient carriers due to their palatability and novelty. However, the formulation of hyaluronic acid (HA) beads presents challenges due to its high viscosity, relatively high intake requirements, and potential interactions with calcium. In this study, the reverse spherification method was applied to reduce core solution viscosity and increase the HA concentration to 6 mg/mL in the beads, clarifying the relationship between HA system viscosity and sphericity. Results from zeta potential, circular dichroism (CD), FTIR, and ITC analyses suggested that HA may form a thermodynamically stable chelate with calcium, leading to a reduction in system viscosity. This may be attributed to the contraction of HA chains, leading to a reduction in their hydrodynamic radius values. Also, the presence of HA impeded calcium ion diffusion. Therefore, by optimizing calcium lactate concentration and employing a secondary calcium bath, high-quality gel beads were obtained with a membrane thickness of 0.101 mm and a rupture force of 1717 g. This study provided a novel product option for oral HA supplementation.