Development of hydrogel-nanoparticle systems for wound healing

Inês Vitória Duarte

Key information

Authors:

Inês Vitória Duarte (Inês Vitória Duarte)

Supervisors:

Pedro Ricardo Martins Lopes da Fonte; Duarte Miguel De França Teixeira dos Prazeres (Duarte Miguel De França Teixeira dos Prazeres)

Published in

01/25/2021

Abstract

Chronic wounds present a challenging problem, since current therapies are not effective, with extended healing time, high recurrence rates and risk of amputations. Insulin is among the cheapest growth factors available, stimulating wound healing and reducing healing time. However, the harsh proteolytic effect in the wound bed requires a delivery system (DS) able to protect insulin from degradation. The aim was to develop an insulin-loaded multifunctional nanoparticle-hydrogel DS to accelerate wound healing. Insulin-loaded chitosan-coated PLGA nanoparticles were produced by w/o/w double emulsion technique and embedded in hydrogels obtained by freeze-thawing. The DS was optimized by quality-by-design approach. Nanoparticles were characterized by DLS and SEM, and hydrogels by rheology and FTIR. Insulin structure was evaluated by CD, and in vitro release profile, cell scratch and cytotoxicity tests were performed. The nanoparticles showed particle size increase and positive ZP change, showing an effective chitosan coating. SEM images showed that nanoparticles incorporated into the hydrogel, maintaining its features without signs of particle aggregation. The results revealed that insulin structure was preserved upon encapsulation and production of the hydrogel. The nanoparticle-hydrogel allowed a sustained insulin release of 10% and 25% up to 72h, for the insulin uncoated and chitosan coated nanoparticles, respectively. In vitro cell scratch assay did not show enhanced cell migration for the hydrogel-nanoparticles systems developed, but showed enhanced cell migration for the culture medium with insulin, closing the gap at 36h, versus 48h for the other conditions. The cytotoxicity was evaluated and all hydrogels were considered biocompatible.