PLLA/ Gel@BBR Three dimensional nano scaffold: simulating the inner ear microenvironment to protect hair cells from neomycin damage

Research background and material design: Sensory sensorineural hearing loss (SNHL) is the most common type of hearing impairment in clinical practice, characterized by irreversible damage to cochlear hair cells (HCs) and spiral ganglion neurons (SGNs). Due to the lack of intrinsic regenerative ability in mammalian inner ear hair cells, damage often leads to permanent hearing loss. In recent years, two-dimensional (2D) culture systems have made progress in supporting auditory cell regeneration, but regenerating hair cells cannot form mature functional cilia bundles, and it is also difficult to establish synaptic connections with spiral ganglion neurons, making it difficult to achieve true physiological hearing recovery. Constructing a three-dimensional (3D) system capable of reproducing the inner ear microenvironment has become a key direction for studying treatment strategies for SNHL. In this context, researchers used poly (L-lactic acid) (PLLA) and gelatin (Gel) as substrates to prepare two-dimensional nanofiber membranes through electrospinning technology, which were then freeze-dried and successfully transformed into three-dimensional PLLA/ Gel@BBR Nano scaffolds. The stent is loaded with BBR (berberine) to construct an inner ear organoid model and evaluate its protective effects on hair cell growth and neomycin (Neo) – induced ototoxicity.

Key findings and material properties

The research results indicate that the inner ear organoids constructed based on this three-dimensional nano scaffold can effectively simulate the physiological microenvironment of the Corti apparatus in the inner ear.

. This system has drug sustained release capability and can protect damaged auditory cells from ototoxic damage. This discovery provides promising ideas for developing new strategies to protect auditory cells and treat sensorineural hearing loss. From a material perspective, PLLA/Gel composite nano scaffolds combine the mechanical tunability of synthetic polyester with the biological activity of gelatin. The freeze-drying process endows them with a three-dimensional porous structure, which is conducive to cell infiltration and nutrient transport. Electrospinning provides a nanoscale fiber morphology that can simulate the topological features of extracellular matrix. The loading and sustained release functions of BBR further expand the potential application of the stent in local treatment.

Significance for the polymer additive industry

Although this study did not directly involve polymer additives, its material system provides new ideas for the application of medical polymers in the field of auditory restoration.

. PLLA, as a biodegradable medical polymer, may affect the performance stability of the final product due to the sensitivity of its molecular chains to heat, oxygen, and processing stress during the processing of nanofibers and three-dimensional scaffolds. In the design of medical polymer materials, the selection of weather stability and antioxidants is of practical significance for maintaining the consistency of material performance during sterilization, storage, and in vivo degradation processes. For example, in processing steps such as electrospinning and freeze-drying, adding an appropriate amount of antioxidant can help suppress the thermal oxidative degradation of PLLA, ensuring the integrity of fiber morphology and scaffold structure. In addition, medical packaging materials need to ensure that the stent is protected from moisture, oxygen, and other factors during transportation and storage, which also requires the barrier performance and stability of the packaging materials. For medical material developers, this study suggests that when constructing three-dimensional nano scaffold medical polymer systems, in addition to focusing on biological activity and drug release function, it is also necessary to systematically evaluate the stability of the materials during processing and sterilization, and use weather resistant stability and antioxidant strategies reasonably to ensure batch consistency and clinical safety of the products. In the future, with the deepening of research on inner ear organoids and three-dimensional scaffolds, medical polymer materials are expected to play a more important role in the treatment of sensorineural hearing loss.

Information source:The PLLA/ Gel@BBR 3D Nanoscaffold Protects Hair Cells From Neomycin Damage by Reducing Oxidative Stress， Organized by Herun Chemical.