Hofmeister Ions-Induced Thinning of Gelatin to Enhance 3D Printing Precision

Abstract

Hydrogel 3D printing holds immense potential in fields like personalized medicine, regenerative therapies, and organ creation, offering biocompatible structures similar to the extracellular matrix. Gelatin-Methacryloyl (GelMA) emerges as a promising candidate, while its high viscosity poses a significant challenge, especially in vat photopolymerization-based 3D printing. Here, a new approach is presented by using Hofmeister ionic effect to substantially reduce the viscosity of high-content (up to 60%) Gelatin bioink at room temperature with enhanced mechanical performance of the printed structures. The thinning effect induced by chaotropic Hofmeister ions is investigated through complex viscosity analysis, optical rotation measurements, and sol–gel conversion studies. The thinning effect induced by chaotropic ions enables precise 3D printing of Gelatin hydrogel, achieving accuracy comparable to prints made with polymers. Furthermore, after polymerization, the cations of the chaotropic salt change their role to cross-linkers, leading to stronger scaffolds that exhibit biocompatibility with robust cell attachment, proliferation, and suitability for cell growth. The combination facilitates the creation of customizable structures and high printing accuracy will promote the wide application of Gelatin in the development of patient-specific implants, drug delivery systems, and tissue scaffolds, further improving medical treatment efficacy and personalized healthcare.