Tackling Multidrug Resistance and Cancer
Multidrug-resistant (MDR) pathogens and cancer represent two of the most significant health challenges globally. Misuse of antibiotics has contributed to a “post-antibiotic era,” while tumors increasingly exhibit resistance to chemotherapeutics. Current treatments for both conditions are associated with severe limitations and side effects, underscoring the urgent need for innovative therapeutic solutions.
Developing Innovative Nanotechnological Solutions
A collaborative research team led by Hassan et al. from Egyptian institutions synthesized selenium nanoparticles (SeNPs) using Streptomyces parvulus MAR4 and developed their chitosan nanoconjugates (Se/Ch-nanoconjugate). The study, published in BMC Microbiology (2024), evaluated these nanoparticles for their potential as antimicrobial and anticancer agents, leveraging environmentally friendly biosynthesis methods.
Biosynthesis and Characterization of Nanoparticles
The SeNPs were biosynthesized by incubating the supernatant from S. parvulus MAR4 with sodium selenate, resulting in a color change to deep orange, indicative of nanoparticle formation. Nanoparticle characterization showed the following results:
- SeNPs Morphology: Spherical with an average diameter of 94.2 nm (range: 48.8–129 nm) confirmed by TEM imaging.
- Se/Ch-nanoconjugate Morphology: Semi-spherical with an average diameter of 74.9 nm (range: 39.7–98.1 nm).
- Stability: Zeta potential values were 37.08 mV for SeNPs and 55.91 mV for Se/Ch-nanoconjugates, confirming enhanced stability in the conjugate.
- Hydrodynamic Diameter: 196.2 nm for SeNPs and 476.6 nm for Se/Ch-nanoconjugates, measured via DLS, indicating successful conjugation.
The study employed advanced methods, including UV-Vis spectroscopy, FTIR, and SEM-EDX, to confirm the structural and functional properties of the nanoparticles.
Promising Antimicrobial and Anticancer Outcomes
Antimicrobial Activity
- Pathogen Sensitivity: Salmonella typhi and Proteus vulgaris were the most sensitive to the Se/Ch-nanoconjugate. For example, P. vulgaris exhibited enzyme inhibition rates as high as 82.4% (phosphoglucose isomerase) and 90.0% (nitrate reductase) with Se/Ch-nanoconjugate, compared to 30.9% and 35.0% inhibition, respectively, with SeNPs.
- Overall Activity: The order of antimicrobial effectiveness was Se/Ch-nanoconjugate > SeNPs > nano-chitosan (NCh).
Anticancer Properties
- Cytotoxicity Data:
- HepG2 (Hepatocellular carcinoma): IC50 = 11.82 μg/mL for Se/Ch-nanoconjugate and 13.04 μg/mL for SeNPs.
- Caki-1 (Renal carcinoma): IC50 = 7.83 μg/mL for Se/Ch-nanoconjugate and 21.35 μg/mL for SeNPs.
- WI-38 (Normal fibroblasts): IC50 = 153.3 μg/mL for Se/Ch-nanoconjugate and 85.69 μg/mL for SeNPs.
The results highlighted the nanoconjugate’s selective cytotoxicity, showing low toxicity to normal cells while effectively targeting cancer cells.
A Leap Toward Biomedical Applications
The study showcased a highly efficient, cost-effective, and safe strategy for biosynthesizing selenium nanoparticles (SeNPs) using the supernatant of Streptomyces parvulus MAR4. Conjugating these SeNPs with nano-chitosan (NCh) yielded a nanoconjugate (Se/Ch-nanoconjugate) with remarkable antimicrobial and anticancer properties. The nanoconjugate demonstrated potent activity against tested microbial pathogens and tumor cell lines, all while showing minimal toxicity to normal cells.
This enhanced activity is attributed to the combination of multiple bioactive agents with diverse mechanisms of action. The conjugation not only improved the biocompatibility and biological activity of each component but also decreased their toxicity. The Se/Ch-nanoconjugate’s strong positive charge facilitated electrostatic interactions with negatively charged cell membranes, leading to cell damage and growth inhibition. Furthermore, the study highlighted the inhibition of key metabolic enzymes as one of the primary antimicrobial mechanisms of these nanoparticles.
Overall, the Se/Ch-nanoconjugate emerges as a promising candidate for antimicrobial and anticancer applications. However, further research is needed to fully elucidate its precise mechanisms for broader biomedical utilization.
Reference:
Hassan, Mervat G., et al. “Biogenic selenium nanoparticles and selenium/chitosan-Nanoconjugate biosynthesized by Streptomyces parvulus MAR4 with antimicrobial and anticancer potential.” BMC microbiology 24.1 (2024): 21.