Banca de DEFESA: CECÍLIA BRILHANTE ARAGÃO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : CECÍLIA BRILHANTE ARAGÃO
Date: 20/08/2026
TIME: 14:00
LOCAL: https://conferenciaweb.rnp.br/sala/amedea
TITLE:

Synthesis, Characterization, and Biological Assays of Chitosan Nanoparticles and Alginate Hydrogels Containing Nitric Oxide Donors for Biomedical Applications

PAGES: 100
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUMMARY:

Fundamental processes in cutaneous physiology, such as epidermal homeostasis, inflammatory cascades, wound repair, and the regulation of cell proliferation and migration, are strictly governed by nitric oxide (NO). Produced by keratinocytes, fibroblasts, and immune cells, NO exerts highly concentration-dependent effects, ranging from the promotion of physiological signaling and wound healing to cytostatic and antiproliferative outcomes. Within this context, the controlled modulation of NO release emerges as a promising strategy for dermatological conditions associated with epidermal hyperproliferation, exacerbated inflammation, and dysregulated tissue remodeling. Thus, the present study aimed to develop and evaluate an alginate hydrogel platform containing chitosan nanoparticles (CSNPs) for the sustained release of S-nitrosoglutathione (GSNO), a NO donor, exploring its biological effects on human keratinocytes. The CSNPs (80 nm, positive surface charge) were synthesized via ionotropic gelation under optimized conditions and incorporated into alginate hydrogels, forming a porous and interconnected three-dimensional matrix with thermal stability and tunable viscoelasticity. Structural characterization confirmed the successful integration of the NO-releasing nanoparticles into the hydrogel matrix. Rheological measurements revealed a predominantly elastic behavior (G′ > G″) and tunable viscosity-related properties, depending on the incorporation of GSNO and chitosan nanoparticles. The decomposition kinetics of GSNO, monitored via UV-Vis spectroscopy, demonstrated sustained NO release for at least 72 hours. In vitro assays revealed that hydrogels with CSNP-encapsulated GSNO incorporated into the alginate matrix (H_GSNO-CS) and the hydrogel with free GSNO (H_GSNO) followed Higuchi kinetics, consistent with Fickian diffusion of GSNO. Electrochemical quantification confirmed that the released NO reached therapeutic levels (24.70 ± 4.18 μmol NO·g⁻¹ for H_GSNO-CS and 20.56 ± 2,69 μmol NO·g⁻¹ for H_GSNO). Cell viability was evaluated in human keratinocytes (HaCaT) via the alamarBlue assay (24 h), while cell migration was investigated using a scratch assay. The formulations exhibited viability statistically similar to the control between 50 and 250 μmol L⁻¹ (GSNO equivalent), demonstrating their cytocompatibility. Despite the preservation of cell viability, the H_GSNO and H_GSNO-CS hydrogels (1–5 mmol L⁻¹) drastically reduced keratinocyte proliferation, limiting cellular expansion to less than 100 μm, compared to the ~700 μm observed in the control group. Additionally, the cells located at the wound margins maintained monolayer morphological integrity without apparent signs of cell death, suggesting a predominantly cytostatic effect associated with the controlled release of NO. To confirm this cytostatic effect, flow cytometry was performed, revealing that the formulations containing chitosan arrested the cells in the quiescent state (G0). Taken together, these results demonstrate that the hybrid hydrogels constitute a promising and biocompatible platform for modulating epidermal dynamics in cutaneous conditions associated with dysregulated proliferation and tissue remodeling.

 

COMMITTEE MEMBERS:
Presidente - Interno ao Programa - 1844792 - AMEDEA BAROZZI SEABRA
Membro Titular - Examinador(a) Externo ao Programa - 1600878 - ARNALDO RODRIGUES DOS SANTOS JUNIOR
Membro Titular - Examinador(a) Externo ao Programa - 1761120 - DANILO JUSTINO CARASTAN
Membro Suplente - Examinador(a) Externo ao Programa - 3476203 - JOSE MARCOS SANCHES JUNIOR
Membro Suplente - Examinador(a) Externo ao Programa - 2347767 - MATHILDE JULIENNE GISELE CHAMPEAU