Hyaluronic acid: Innovations and prospects in biology and medicine

Hyaluronic acid (HA) is a natural glycosaminoglycan found in all tissues and body fluids of vertebrates, including those of humans. Its biological functions vary with molecular weight. As the main component of the extracellular matrix, HA, owing to its high water-binding capacity, plays a critical role in maintaining tissue hydration, osmotic balance, lubrication, and cellular activity. It influences cell proliferation, differentiation and migration, inflammation, immunomodulation, angiogenesis, and other biological processes. This article reviews recent advances in HA applications across regenerative medicine, orthopedics, derma tology, neurology, dentistry, cosmetology, cryobiology, drug delivery, oncology, and the food industry. E ffectiveness of HA in wound healing depends largely on its molecular weight: high molecular weight HA exhibits immunosuppressive and anti-inflammatory effects, whereas low molecular weight HA promotes immunostimulation and amplifies inflammation. Hydrogels based on HA and its derivatives have gained prominence as potential treatments for bone diseases. Advances in 3D printing enable precise control of scaffold architecture and porosity, which is essential for mimicking native bone tissue, and allow int e gration of HA-based hydrogels with other materials to generate composite scaffolds with enhanced performance. In dentistry, HA is commonly used for diverse procedures, including papilla regeneration injections, implant coating, topical treatment of oral ulcers, supplementation to platelet-rich fibrin, plasma and growth factors, use as a matrix for encapsulation of stem cells and signalling molecules and as a nanocarrier of drugs, and therapy of denture- or surgery-induced stomatitis and irritation. In op h thalmology, HA is used in eye drops to relieve eye dryness and to improve contact lens tolerance. Due to its viscosity, HA is useful in various ophthalmic procedures, including cataract surgery, vitreoretinal surgery and glaucoma treatment. In cryobiol o gy, HA is being explored as part of complex cryoprotectant formulations. For example, HA is known to be able to neutralize free radicals and to protect cells from reactive oxygen species generated by cryoprotectants. The article also highlights prospects for the rising use of innovative HA-based products to advance current medical practices and biotechnologies.