# Combination of Collagen-Chitosan Hydrogel and Injectable Platelet-Rich Fibrin as a Biomaterial for Bone Regeneration: Characterization and Growth Factor Release Pattern

## TL;DR

This study explores combining collagen-chitosan hydrogels with platelet-rich fibrin to improve bone regeneration by extending the release of growth factors.

## Contribution

The novel contribution is demonstrating a sustained growth factor release pattern when combining I-PRF with collagen-chitosan hydrogels.

## Key findings

- The collagen-chitosan hydrogel structure remains unchanged after incorporating I-PRF.
- The combination of I-PRF and hydrogel provides a more stable and prolonged release of TGF-β1 and PDGF-AB.
- The sustained release suggests potential for improved bone regeneration applications.

## Abstract

The release of growth factors in injectable platelet-rich fibrin (I-PRF) exhibits a peak within 24 hours and subsequent decline by day 10, underscoring immediate application, limiting its effectiveness in alveolar bone repair. In order to enhance its regenerative potential, I-PRF can be combined with biomaterial scaffolds such as collagen-chitosan hydrogels, which mimic the extracellular matrix and support tissue regeneration. This combination has been shown to enhance cellular signaling and tissue repair. This study aimed to analyze the characterization of collagen-chitosan hydrogels with I-PRF and determine the growth factor release pattern that occurs after mixing.

Collagen-chitosan hydrogels were prepared and combined with I-PRF at a 1:1 ratio. The structural characterization of these hydrogels, both with and without I-PRF, was performed using Fourier transform infrared spectroscopy (FTIR), enabling the comparison of absorption bands. Furthermore, the release profiles of transforming growth factor-beta 1 (TGF-β1) and platelet-derived growth factor AB (PDGF-AB) were assessed in two experimental groups: The first group consisted of I-PRF alone, while the second group comprised of I-PRF combined with collagen-chitosan hydrogels. Growth factor release was evaluated at multiple time points (days 1, 3, 5, 7, 9, 11, 13, 15, and 17) using enzyme-linked immunosorbent assay. The resulting absorbance values were converted into concentration measurements (pg/mL) using a standard calibration curve. Statistical analysis was conducted using two-way analysis of variance followed by a
post hoc
least significant difference test.

FTIR analysis demonstrated that the functional groups present in the collagen-chitosan hydrogel remained unchanged following the incorporation of I-PRF, confirming the formation of physical rather than chemical bonds. Subsequent analysis revealed statistically significant differences in the release patterns of TGF-β1 and PDGF-AB between the two groups (
p
 < 0.05). The combination of collagen-chitosan hydrogel and I-PRF exhibited a more stable and sustained release profile from day 1 to day 17.

The combination of I-PRF with collagen-chitosan hydrogels does not alter the fundamental chemical structure of the scaffold. However, this combination does influence the controlled release of growth factors. This finding indicates that the synergistic interaction between collagen and chitosan enhances the hydrogel's properties, suggesting its potential as a promising biomaterial for use as a scaffold in bone regeneration.