Work

α-pinene and β-sitosterol co-loaded alginate/gelatin-functionalized niosomes for enhanced antibacterial and anti-biofilm activity against methicillin-resistant Staphylococcus aureus and carbapenem-resistant Klebsiella pneumoniae

Year: 2026

Type: article

Abstract: BACKGROUND: The rise of antibiotic resistance in infectious disease, particularly from carbapenem-resistant Klebsiella pneumoniae (CRKP) and methicillin-resistant Staphylococcus aureus (MRSA), poses a significant global health challenge. This study aimed to fabricate and evaluate a novel biocompatible hydrogel scaffold (Nio-PIN/STL@SC) incorporating niosomes loaded with α-pinene (PIN) and β-sitosterol (STL) to enhance antibacterial and anti-biofilm activities against MRSA and CRKP isolates. METHODS: Niosomes containing PIN and STL (Nio-PIN/STL) were prepared using the thin-layer hydration method and then incorporated into an alginate/gelatin hydrogel scaffold via a straightforward crosslinking reaction, forming Nio-PIN/STL@SC. The physicochemical properties of the scaffolds were characterized using DLS, SEM, TEM, and FTIR. In vitro assays assessed drug release, swelling, degradation, stability, cytotoxicity, antibacterial efficacy (MIC, disk diffusion, time-kill assay), anti-biofilm activity (CV assay, MBEC), and the expression of biofilm-related genes. RESULTS: The optimized Nio-PIN/STL@SC exhibited an average particle size of 263.5 ± 5.2 nm, Polydispersity Index (PDI) of 0.231 ± 0.011, and entrapment efficiencies (EE%) of 78.2 ± 1.18% (PIN) and 79.7 ± 1.35% (STL). The scaffold demonstrated a sustained biphasic release profile, with only 40.85% of PIN and 43.25% of STL released over 72 h at pH 7.4. Nio-PIN/STL@SC showed markedly enhanced antibacterial activity, with MIC values of 0.97-1.95 µg/mL against MRSA and 0.97-3.9 µg/mL against CRKP, representing at least a 16-fold reduction compared to free drugs. MBEC values revealed a significant reduction in biofilm biomass, decreasing viable MRSA and CRKP cells to approximately 2.0 and 3.5 log10 CFU/mL, respectively. qRT-PCR analysis demonstrated significant downregulation of icaA and icaD in MRSA and mrkA, mrkD, and fimA in CRKP (P < 0.001), alongside upregulation of the biofilm repressor gene icaR. CONCLUSIONS: The developed Nio-PIN/STL@SC hydrogel scaffold demonstrates a promising drug delivery system for the synergistic enhancement of antibacterial and anti-biofilm activities against multidrug-resistant pathogens like MRSA and CRKP with reduced cytotoxic effects, suggesting its potential for treating bacterial infections. Further in vivo studies are warranted to validate these findings. CLINICAL TRIAL NUMBER: Not applicable.

Source: BMC Biotechnology

DOI: 10.1186/s12896-026-01132-2

Authors: Hoda Ghoraba, Fatemeh Ashrafi, Rezvan Mousavi Nadushan, Hosein Abbaspour

Institutions: Islamic Azad University, Tehran, Islamic Azad University North Tehran Branch, Islamic Azad University Central Tehran Branch

Language: English

Topic: Hydrogels: synthesis, properties, applications

Subfield: Molecular Medicine

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $2,990