Multifunctional Agarose-Based Biomaterials: From Tissue Engineering and Immunomodulation to Advanced Diagnostics and Translational Applications

Agarose, a naturally derived marine polysaccharide extracted from red algae, has evolved from a conventional electrophoretic matrix into a multifunctional biomaterial platform for biomedical engineering. Its thermoreversible gelation, tunable pore structure, optical transparency, generally low immunogenicity under tested conditions, and chemical modifiability enable applications in tissue engineering, drug delivery, molecular diagnostics, immunomodulation, and cell preservation. This review critically examines recent advances in agarose-based biomaterials, with emphasis on structure–property relationships, stimulus-responsive delivery systems, regenerative scaffolds, immune–material interactions, agarose-enabled diagnostic microdevices, and DMSO-free cryopreservation. Representative developments include proof-of-concept microfluidic detection of a cfDNA surrogate and histones in spiked plasma, agarose composite hydrogels for controlled release and osteochondral repair, agarose-containing composite hydrogels investigated for macrophage modulation, and agarose/trehalose systems that provide immediate post-thaw viability comparable to conventional DMSO-based preservation in the reported cell model, although post-thaw proliferation remained lower. Agarose is commercially established in electrophoresis and bioseparation, whereas therapeutic delivery and implantable regenerative systems remain predominantly preclinical. Remaining barriers include limited in vivo degradability, insufficient intrinsic cell adhesiveness and bioactivity, trade-offs among mechanical strength, injectability and printability, and incomplete manufacturing and regulatory standardization. Future work should prioritize well-defined degradation pathways, reproducible composition–property relationships, application-specific benchmarking, and clinically relevant validation.