(168g) Crosslinked Alginate-Based Nanofibers for Biomedical Applications

Alginate is an excellent candidate for biomaterials due to its water-solubility, biocompatibility, and gelation with biocompatible calcium ions under mild conditions. However, the rigid structure and high conductivity of alginate chains typically make it difficult to process into nanostructures like nanofibers which would be beneficial for applications in drug delivery, wound dressing, and extracellular matrices. Furthermore, current studies on crosslinking alginate-based fibers use ethanol as a pretreatment and/or co-solvent which can be damaging to various mammalian cells, bacterial cells, and proteins. In this work, we fabricated crosslinked, alginate-based nanofibers for biomedical applications. First, we systematically studied the effects of a carrier polymer, polyethylene oxide (PEO), and an FDA-approved surfactant, polysorbate 80 (PS80) on fiber formation. PEO and PS80 decreased the surface tension and conductivity of alginate solutions to facilitate smooth fiber formation which was confirmed using scanning electron microscopy (SEM). Next, we proposed the use of acidic, neutral, and basic pH for aqueous calcium crosslinking solutions and glycerol as an alternative co-solvent to create chemically resilient alginate-based nanofibers. We analyzed fiber diameter, morphology, and composition before and after crosslinking using scanning electron microscopy, Fourier Transform Infrared spectroscopy, and thermogravimetric analysis and found that our crosslinking systems could influence both fiber diameter and composition. Finally, we determined the stability of the fibers when submerged in acidic buffer, DI water, and phosphate buffer saline (PBS) over time. SEM micrographs showed crosslinked nanofibers were stable in acid buffer and DI water but tended to swell and merge into a film in PBS. This work provides important information for creating crosslinked alginate nanofibers for a variety of biomedical applications.