Injectable Micro-Hydrogel for DNA Delivery: A Promising Therapeutic Platform.

Utilizing the immune system as a strategy for disease prevention and treatment is promising, especially with dendritic cells (DCs) playing a central role in adaptive immune responses. The unique properties of DCs drive interest in developing materials for cell-based therapy and immune modulation. Injectable systems require syringe-compatible scaffolds, while hydrogels, like alginate, known for their programmability and biocompatibility, offer a versatile platform for immune medicine enhancement through easy preparation and room-temperature cross-linking. In this study, we synthesized alginate balls loaded with DCs or cytosine-phosphorothioate-guanine deoxyribonucleotide (CpG DNA) microparticles, aiming for long-term immune cell culture with potential immune stimulation effects. Encapsulated DCs exhibited proliferation within the alginate balls for up to 7 days, and CpG MPs were uniformly dispersed, which can facilitate uptake by DCs. This was supported by the result that DCs effectively phagocytosed CpG microparticles in a 2D environment. After the uptake of CpG MPs, the alginate balls with CpG-MP-uptaken DCs were synthesized successfully. The injectable properties of the alginate balls were easily modulated by adjusting the syringe needle gauges. This innovative strategy holds substantial promise for advancing medical treatments, offering effective and comfortable solutions for controlled immune modulation.