Collagen Films Cross-linked with Hydroxyapatite: Preparation and Properties

Background: The study focuses on producing collagen films cross-linked with hydroxyapatite (HAP), which will subsequently serve as material for creating collagen sponges for bone tissue regeneration. The relevance of the study lies in the use of zander skin, a fish byproduct, as a raw material. This study aims to compare cross-linking agents: glutaraldehyde and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS), and identify the most suitable agent. Methods: The surface of the cross-linked films was analyzed using a scanning electron microscope, the composition of the films was determined by attenuated total reflectance infrared spectroscopy, and the stability of the films was determined by collagenase degradation. Results: Based on the results obtained, it was concluded that cross-linking collagen with HAP using EDC/NHS is the most suitable and gentle method. The collagen film sample cross-linked with EDC/NHS has the narrowest distribution with a maximum particle size of 17 μm and a minimum average value (approximately 8 μm). Infrared spectroscopy showed preservation of the native protein structure (presence of a peak at 1516 cm − 1 (amide II), in addition to peaks characteristic of HAP at 561 cm −1 and 1030 cm −1 ). Collagenase analysis confirms a good degree of cross-linking (the amount of cleaved glycine did not exceed 0.015 ± 0.004 mM). Conclusion: The results demonstrate the promising application of the EDC/NHS crosslinking agent for fabricating collagen/HAP films. These films are intended for use as a material to produce biopreparations applied in regenerative medicine, particularly in dentistry.