# Biomimetic HA-Reinforced PCL/PLA Fibrous Structures via Solution Blow Spinning: Cocoon-Inspired Design for Bone Regeneration

## TL;DR

Researchers created biomimetic structures inspired by moth cocoons to improve bone regeneration using biodegradable polymers and hydroxyapatite.

## Contribution

A novel method for fabricating HA-reinforced PCL/PLA fibrous structures using solution blow spinning and cocoon-inspired design.

## Key findings

- Cocoons consist of fibroin in a sericin matrix with HA particles, forming a multilayered structure.
- A six-layer fibrous membrane pressed at 90°C showed the highest mechanical strength.
- Bioinspired structures replicated cocoon morphology and exhibited osteoconductive potential.

## Abstract

Bioinspired materials have been studied for applications
in various
fields, including aerospace and tissue engineering. In this study,
biomimetic fibrous structures, inspired by the cocoons of the Rothschildia sp. moths, were produced by solution
blow spinning (SBS) using biodegradable polymers such as polycaprolactone
(PCL) and poly­(lactic acid) (PLA), selected for their distinct melting
temperatures, enabling the fabrication of hot-pressed fiber-reinforced
composites, with the addition of hydroxyapatite (HA) microparticles,
due to its osteoconductive capacity. Cocoons were analyzed using scanning
electron microscopy (SEM), tensile tests, Fourier-transform infrared
spectroscopy (FTIR), and thermogravimetry (TG) and differential scanning
calorimetry (DSC). The results showed that cocoons consist of fibroin
dispersed in a sericin matrix, interspersed with HA particles, forming
a fibrous multilayered structure. To replicate this structure, fibrous
layers were produced using a multinozzle SBS system that spun PLA
(fibrous phase) and PCL (matrix). A hot-press process at varying temperatures
and spun layers was applied to melt PCL while preserving the fibrous
morphology of PLA. Characterization of the bioinspired structures
followed the same techniques used for the cocoons, revealing similar
morphology with PLA fibers in a PCL-HA matrix. Mechanical strength
varied, with the six-layer fibrous membrane, pressed at 90 °C
for 30 min, exhibiting the highest strength. Overall, this research
demonstrates the potential of developing bioinspired nanocomposites
with customized properties based on the structure of moth cocoons.