Experimental and Finite Element Analysis of a Residual Hair Keratin-based Hydrogel with Calcium for Atorvastatin Sequestration, Release, and In Vitro Activity

Abstract

Excessive fibrosis impairs tissue regeneration by promoting extracellular matrix deposition and fibroblast activation. This study introduces keratin-based hydrogels (KRT) derived from residual human hair as sustainable carriers for localized atorvastatin (Ator) delivery. Calcium incorporation (CKRT) enhanced electrostatic interactions with Ator, improving sequestration and modulating release kinetics. Comprehensive characterization of KRT included chemical composition (FTIR, DSC), charge properties (pI = 5.5; net negative charge = -15.43 µmol/g), porosity (89%), and rheology (shear-thinning, linear viscoelastic region up to 24.5% strain, thermal stability to 68°C). Ator release followed Korsmeyer-Peppas kinetics (r² > 95%), and finite element analysis validated experimental profiles (r² = 82%-95%) while estimating diffusivity reductions from 569 to 0.06 µm²/s within the gel matrix. In vitro assays confirmed CKRT biocompatibility (ISO 10993-5) and preserved Ator bioactivity, with EC₅₀ values of 208 µm for mesenchymal stem and 389 µm for fibroblast cell lines. These findings demonstrate that CKRT provides a robust platform for controlled anti-fibrotic drug delivery, supported by extensive physicochemical and mechanical characterization.

Keywords: atorvastatin drug absorption and release; calcium linker; fibroblast inhibition; finite element analysis; keratin and residual hair biomaterials.