Complex Characterization of Nanofiber Biomaterials Based on Chitosan, Collagen and Fish Gelatine Produced by Electrospinning*

Electrospinning is an increasingly used technique for producing nanofibers from various types of polymers and biopolymers. These fibers are suitable for applications in tissue engineering, wound healing and drug delivery. In this study, we focused on biomaterials produced from raw marine fish collagen, fish gelatin and chitosan. Various collagen/chitosan and fish gelatin/chitosan in several ratios were dissolved in acetic acid. The formed solutions have concentrations in the range from 5 to 90% (g/ml). The effect of different molecular formats (native and denatured collagen) was studied. The prepared solutions were used in electrospinning experiments. The order degree of various phases of raw materials was established from x-ray diffraction (XRD) measurements. The raw materials, bio-polymeric solutions and finite nanofibers biomaterials were characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), low-field 1D NMR (nuclear magnetic resonance) relaxometry, 2D NMR T1-T2 COSY (correlation spectroscopy), T1-T2 EXSY (exchange spectroscopy) maps, and high field localized 1H NMR spectroscopy. The T2-T2 EXSY experiments showed that the number of components characterized by distinct dynamics is larger than those that can by estimated from 1D T2-distributions due to molecular exchange. Moreover, the full complexity was also revealed by T1-T2 COSY maps. The study provides a better understanding of the nanofiber properties, demonstrates the potential of electrospinning for producing nanofibers, and highlights the importance of using multiple characterization methods for a better understanding of the properties of biological nanofibers.