# Characterization and Structural Evaluation of Niobium-Integrated Chitosan–Gelatin Hybrid Hydrogels

## TL;DR

This study enhances chitosan-gelatin hydrogels by integrating niobium pentoxide nanoparticles, improving their mechanical strength and stability for biomedical applications.

## Contribution

The novel integration of niobium pentoxide nanoparticles into chitosan-gelatin hydrogels enhances their structural and mechanical properties.

## Key findings

- SEM imaging showed architectural changes with increased Nb2O5 content, leading to heterogeneous pore structures.
- G2 hydrogel demonstrated optimal swelling (298%) and gel fraction (91%), indicating improved stability.
- Rheological tests confirmed G2's superior elasticity and shear-thinning behavior.

## Abstract

Chitosan–gelatin (CG) hybrid hydrogels are widely recognized for their biocompatibility and suitability for soft tissue engineering, wound dressings, and biomedical coatings. Despite this promise, conventional CG systems often exhibit limited mechanical strength, restricted durability, and uncontrolled swelling, which can reduce their clinical relevance. In this study, we introduce an enhanced soft hydrogel platform reinforced with niobium pentoxide (Nb2O5) nanoparticles and chemically crosslinked using glutaraldehyde, with citric acid serving as a dissolution medium and processing aid. Three hydrogel variants (G1, G2 and G3) were prepared by adjusting nanoparticle concentration and subsequently evaluated through structural, morphological, swelling, gel-fraction, and rheological analyses. SEM imaging revealed that increasing Nb2O5 content produced notable architectural transitions—from smooth porous matrices to nanoparticle-distributed, heterogenous pore structures. XRD, FTIR, and Raman spectroscopy confirmed the structural retention of Nb2O5 and its effective interaction with the polymer network. Swelling and gel-fraction measurements demonstrated improved network stability in nanoparticle-loaded systems, with G2 providing the most desirable balance between swelling capacity (298%) and gel fraction (91%). Rheological studies further identified G2 as the most stable and elastic composition, exhibiting strong shear-thinning behavior and high structural recovery. Overall, G2 emerges as the optimal formulation for future biomedical development.