Multifunctional lanthanum oxide-doped carboxymethyl cellulose nanocomposites: A promising approach for antimicrobial...

This study presents the synthesis and characterization of lanthanum oxide (La₂O₃)-doped carboxymethyl cellulose (CMC) nanocomposites via a solution casting method, designed to offer an eco-friendly, multifunctional material with significant potential in biomedical applications. Structural analysis using FTIR, XRD, and EDX confirmed successful La₂O₃ integration, with FTIR spectra indicating a distinctive LaO stretching peak at 628.2 cm^-1, XRD patterns revealing enhanced crystallinity with notable peaks at 16.6°, 27.6°, and 49.8°, and EDX showing a uniform lanthanum distribution with a 10.41 mass% concentration. These enhancements in structural stability and crystalline properties underscore the composite's functional robustness. Biological assessments revealed the composite's substantial antimicrobial efficacy, demonstrating inhibition zones up to 31 mm against pathogenic strains such as E. coli, S. aureus, E. faecalis, K. pneumoniae, and C. albicans at a 15 wt% La₂O₃ concentration-surpassing conventional antimicrobial agents. Minimum inhibitory concentration (MIC) tests supported these findings, showing MIC values as low as 7.82 μg/mL, further validating the composite's heightened antimicrobial potency compared to pure CMC. In vitro cytotoxicity assays indicated selective anticancer effects of the La₂O₃/CMC nanocomposites, with IC₅₀ values of 327.7 μg/mL and 189.8 μg/mL against PC-3 prostate and A549 lung cancer cells, respectively. Remarkably, the composite showed minimal impact on normal lung fibroblasts (Wi-38), with an IC₅₀ value of 956.8 μg/mL, emphasizing its selectivity towards cancer cells. Collectively, these results highlight the La₂O₃/CMC composite as a biocompatible and multifunctional material suitable for both antimicrobial and targeted anticancer applications, aligning with the growing demand for safe, effective biomedical solutions.