# Biofunctionalization of silk fibroin scaffolds with enamel matrix protein and injectable platelet rich fibrin for soft tissue augmentation: an in-ovo study

## TL;DR

This study explores how silk fibroin scaffolds, modified with proteins and platelet-rich fibrin, can enhance blood vessel growth for tissue healing in an egg-based model.

## Contribution

The study introduces a novel application of silk fibroin scaffolds biofunctionalized with iPRF and EMP for soft tissue regeneration.

## Key findings

- SF matrices showed high vascularization regardless of treatment, suggesting potential for guided tissue regeneration.
- CM matrices with iPRF demonstrated the highest vascularization metrics compared to other groups.
- Gene expression analysis showed high variability but no significant differences between groups.

## Abstract

Silk fibroin (SF) is a biomaterial derived from the cocoon of the mulberry silkworm. This study aimed to assess the capacity of SF matrices biologized with injectable platelet-rich fibrin (iPRF) or enamel matrix protein (EMP) to modulate angiogenesis and immune response in the chorioallantoic membrane (CAM) assay.

300 eggs were divided into the following groups: CM + NaCl, CM + iPRF, CM + EMP, SF + NaCl, SF + iPRF, and SF + EMP. Matrices were applied to the CAM on embryonic development day (EDD) 7 after rehydration. Angiogenesis, represented by vascularized area, vessel density, and vessel junctions, was evaluated on EDD 10, 12, and 14. Additionally, gene expression of HIF-1ɑ, VEGF, MMP-13, and NOS2 was assessed via quantitative polymerase chain reaction (qPCR) on EDD 11 and 14.

The number of vascularized specimens was notably higher in SF matrices regardless of the treatment applied, while in the CM group, only matrices biofunctionalized with iPRF demonstrated vascularization. On EDD 14, the CM + iPRF group exhibited the highest values for total vascularized area (CM + iPRF: 57.52%, SF + iPRF: 21.87%, p < 0.001), vessel density (CM + iPRF: 0.0067 μm/µm2, SF + iPRF: 0.0032 μm/µm2, p = 0.002), number of vessel junctions (CM + iPRF: 14.45, SF + iPRF: 4.82, p = 0.001). Gene expressions displayed high data variability and no significant differences between the groups.

Biofunctionalization with iPRF in CM leads to a high vascularization rate probably through their capability of retaining higher liquid volumes, suggesting improved intraoral wound healing after guided tissue regeneration (GTR). Despite biofunctionalization, SF matrices exhibit a high vascularization, indicating SF as a promising material for GTR.