Layer by layer preparation of Fe3O4@Cg-DTC/AgNPs - Core–shell colloidal antimicrobial and anti-biofilm agent

Sep 30, 2026

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Layer-by-layer fabrication was used to create a core–shell dithiocarbonate carbon functionalized magnetic composite to support and stabilize silver nanoparticles (Ag NPs). Ag NPs were chemically reduced and decorated onto the magnetic core–shell surface, then characterized by FT-IR, XRD, VSM, EDX, SEM, TEM, particle size distribution, and elemental mapping. The support prevented Ag NPs aggregation and maintained uniform dispersion. The resulting Fe3O4@Cg-DTC/AgNPs nanocomposite showed antibacterial activity against E. coli, P. aeruginosa, and S. aureus, with strong biofilm inhibition and no cytotoxicity in NIH-3T3 cells.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages10

Reading Time25 min

AccessFree to download

Introduction

Antibiotic resistance and need for alternatives

Metal nanoparticles and antimicrobial mechanisms

Stabilization strategies and core–shell concepts

Materials and Methods (implied)

Synthesis of Fe3O4@Cg-DTC/AgNPs

Characterization techniques

[www. nature.com/scientificreports](www. nature.com/scientificreports) OPEN Layer by layer preparation of Fe 3 O4 @Cg-DTC/AgNPs as colloidal antimicrobial and anti-biofilm agent Solmaz Ohadian Moghadam1, Lida Lotfollahi Hagghi2, Reza Taghavi3, Mohammad Reza Nowroozi1, Ziba Karimi3, Amir Hasanzadeh2􀀍 & Sadegh Rostamnia3􀀍 To solve antimicrobial resistance in bacteria, metal nanoparticles (NPs) have gained tremendous attention due to their effectiveness and ease of use. Here, we prepared a core–shell dithiocarbonate carbon functionalized magnetic composite and employed it to support and stabilize the silver nanoparticle (Ag NPs). A chemical reduction method was employed to decorate the Ag NPs over the surface of the magnetic composite. The prepared materials were characterized using FT-IR, XRD, VSM, EDX, SEM, TEM, particle size distribution analysis, and elemental mapping. The results demonstrated that the designed support effectively prevented aggregation of the Ag NPs, ensuring their uniform dispersion throughout the structure. The Ag NPs decorated core–shell material was used as an antimicrobial agent against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. The minimum inhibitory concentrations of nanocomposite against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus were 0.58 ± 0.38, 1 ± 0, and 4.67 ± 3.06 µg mL−1, respectively. The results demonstrated that Fe3O4 @Cg-DTC/AgNPs nanocomposite has a stronger antibacterial effect than the control antibiotic, ciprofloxacin. Regarding biofilm inhibition, the lowest concentration of Fe3O4 @Cg-DTC/Ag composite required to inhibit biofilm formation in E. coli was 0.0625 µg mL−1, while the concentrations required for P. aeruginosa and S. aureus were 0.5 and 1 µg mL−1, respectively. Cytotoxicity assays confirmed that the nanocomposite did not induce toxicity in NIH-3T3 cells. Overall, these results demonstrate the potent antibacterial and anti-biofilm activity of the Fe3O4 @Cg-DTC/ AgNPs nanocomposite while maintaining cytocompatibility. Keywords Magnetic NPs, Ag NPs, Dithiocarbonate functionalization, Antibacterial, Anti-biofilm Antibiotic resistance in bacteria is a growing global concern, posing a significant threat to public health1–7. The overuse and misuse of antibiotics have led to the development of resistant strains of bacteria that no longer respond to traditional antibiotic treatments8. This has serious implications for the effectiveness of antibiotics in fighting infections and diseases, potentially leading to higher mortality rates and increased healthcare costs9. The emergence and spread of drug-resistant bacterial strains have become a critical concern in the management of infectious diseases globally10. These challenges have led to increased treatment failures, complications, and pose significant risks to public health11. Organisms involved in these infections include Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (S. aureus), etc12. To prevent such infections, antibiotic prophylaxis with fluoroquinolones is performed. Owing to the growing resistance to fluoroquinolones due to misuse and overuse, the need to seek appropriate alternatives is felt13. One promising approach to address antibiotic resistance is the use of metal nanoparticles (NPs), which possess unique physicochemical properties that enable them to effectively combat resistant bacteria. Among them, silver nanoparticles (Ag NPs) have shown strong antimicrobial activity against a wide range of bacteria, including multidrug-resistant strains14. Their antibacterial properties arise from multiple mechanisms such 1Uro-Oncology Research Center, Tehran University of Medical Sciences, Tehran 14197-33141, Iran. 2Department of Microbiology and Virology, School of Medicine, Urmia University of Medical Sciences, Urmia 57157-99313, Iran. 3Advanced Porous Materials and Energy Technology (APMET) Res. Lab., Department of C

FAQs

How were the Fe3O4@Cg-DTC/AgNPs nanocomposites prepared?

A core–shell dithiocarbonate carbon functionalized magnetic composite was prepared and used to support and stabilize silver nanoparticles, which were decorated onto the magnetic composite via a chemical reduction method.

Which techniques were used to characterize the prepared materials?

The nanocomposites were characterized using FT-IR, XRD, VSM, EDX, SEM, TEM, particle size distribution analysis, and elemental mapping.

What antibacterial and anti-biofilm performance did the nanocomposite show?

The Ag NP–decorated core–shell material inhibited E. coli, P. aeruginosa, and S. aureus and demonstrated biofilm inhibition, with cytotoxicity assays confirming no toxicity in NIH-3T3 cells.

Sep 30, 2026

Upload by Levi