# Effect of natural silk fibers and synthetic fiber-reinforced composites on the cytotoxicity of fibroblast cell lines

## TL;DR

This study compares the cytotoxicity of natural silk and synthetic fibers on fibroblast cells, finding both to be safe and suggesting silk as a potential alternative to synthetic fibers.

## Contribution

The study evaluates natural silk fibers as biocompatible alternatives to synthetic fibers in fiber-reinforced composites.

## Key findings

- All fiber-reinforced composite groups showed over 80% cell viability.
- No significant difference in cytotoxicity was found between natural silk and synthetic fiber groups.
- Bombyx mori and Samia ricini silk fibers show potential as alternatives to synthetic fibers.

## Abstract

Synthetic fibers have many benefits in clinical practice; however, they cause microplastic pollution, and their unaffordable price increases treatment costs. Natural silk fibers require biocompatibility assessment. This study investigated the effects of natural and synthetic fiber-reinforced composites (FRCs) on the cytotoxicity of fibroblast cell lines.

Three commercial synthetic fibers (polyethylene, quartz, and E-glass) and two silk fibers from Bombyx mori and Samia ricini cocoons were employed. These fibers were made into FRC samples (n=6) by impregnation in flowable composite using a brass mold (25×2×2 mm). NIH/3T3 mouse fibroblasts were cultured in Dulbecco’s modified eagle medium, supplemented, and seeded in 2×104 cells/mL. They were stored at 37 °C under 5% CO2 for 24 hours. The FRC samples were made into powder, eluted in dimethylsulfoxide, continued with PBS, supplemented with Dulbecco’s modified eagle medium (DMEM), and exposed to cells for 24 hours. Blank (medium only) and control (cells and medium) samples were included. Subsequently, MTT was added for 4 h and read by enzyme-linked immunosorbent assay (λ=570 nm). Cell viability (%) was calculated and analyzed using one-way ANOVA (α=0.05).

All groups of FRCs showed>80% cell viability. One-way ANOVA showed no significant difference between FRC groups regarding the viability of fibroblast cell lines (P>0.05).

Both natural silk and synthetic fibers exhibit low cytotoxicity to fibroblast cell lines. B. mori and S. ricini silk fibers showed the potential to be used as alternative synthetic fibers.