Synthesis, Physicochemical Characterization, and Antimicrobial Evaluation of Ureasil-Polyether Coatings with Silver Nanoparticles for Hospital Devices

Inorganic Non-Metallic Materials Nanoscience Infectious Diseases Polymer Chemistry Chemistry Materials Science Bioengineering Microbiology Life Sciences Medicine
silver nanoparticles hybrid materials sol-gel process hybrid nanocomposite antimicrobial coatings hospital devices physicochemical characterization

Research Background

Nosocomial infections are a common and serious problem in healthcare settings, particularly on reusable medical devices, where cross-contamination and biofilm formation are major causes. To address this challenge, researchers have begun exploring the use of coating materials containing metallic nanoparticles to prevent microbial attachment and growth. Silver nanoparticles (AgNPs) have garnered significant attention due to their strong antibacterial and antifungal properties. However, effectively integrating AgNPs into medical device coatings while maintaining the material’s physicochemical stability and antimicrobial efficacy remains a pressing issue.

This study aims to develop a hybrid material coating based on silver nanoparticles and ureasil-polyether (U-PEO) for antimicrobial protection of hospital equipment. By synthesizing and characterizing silver nanoparticles and combining them with U-PEO materials, the researchers evaluated the antimicrobial potential of this composite, particularly its inhibitory effects against common nosocomial pathogens such as Staphylococcus aureus, Escherichia coli, and Candida albicans.

Source of the Paper

This paper was co-authored by multiple researchers from Brazil, with the primary authors including Adenia Mirela Alves Nunes, José de Oliveira Alves Júnior, and Mariana Rillo Sato. The research team is affiliated with the State University of Paraíba and the Federal University of Paraiba in Brazil. The paper was accepted on March 31, 2025, and published in the journal Bionanoscience with the DOI 10.1007/s12668-025-01920-8.

Research Process

1. Synthesis and Characterization of Silver Nanoparticles

The researchers first synthesized silver nanoparticles using a chemical reduction method. The specific steps involved reacting silver nitrate (AgNO3) with sodium citrate under alkaline conditions to form a colloidal dispersion of silver nanoparticles. The formation of AgNPs was confirmed using UV-Vis spectroscopy, with a characteristic absorption peak observed at 418 nm. Additionally, the researchers determined the average size of the AgNPs to be 70.4 nm and 101.06 nm using nanoparticle tracking analysis (NTA) and dynamic light scattering (DLS), respectively.

To evaluate the stability of the AgNPs, the researchers conducted photostability and freeze-thaw cycle tests. The results showed that the AgNPs remained stable for 9 days, but significant aggregation was observed on the 10th day, indicating limited stability.

2. Evaluation of Antimicrobial Activity of Silver Nanoparticles

The researchers assessed the antimicrobial efficacy of AgNPs against Staphylococcus aureus, Escherichia coli, and Candida albicans using minimum inhibitory concentration (MIC) tests. The results demonstrated that AgNPs exhibited bactericidal activity against E. coli and fungicidal activity against C. albicans, with MIC values of ≥6.80×10⁷ particles/ml and ≥2.72×10⁸ particles/ml, respectively. However, only bacteriostatic activity was observed against S. aureus, with no complete bacterial eradication.

3. Synthesis and Characterization of U-PEO Hybrid Materials

Next, the researchers synthesized U-PEO hybrid materials using the sol-gel process and incorporated AgNPs at various ratios (1:0.3 to 1:6.67). Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses confirmed the amorphous structure of the U-PEO materials and revealed that the incorporation of AgNPs did not significantly alter the physicochemical properties of the material.

Thermogravimetric analysis (TGA) results showed that the U-PEO materials exhibited good thermal stability up to 300°C, and the addition of AgNPs further enhanced this stability. Additionally, contact angle tests indicated that the U-PEO materials were hydrophilic, and the incorporation of AgNPs slightly reduced the contact angle without significantly affecting wettability.

4. Evaluation of Antimicrobial Activity of the Composite Material

The researchers assessed the antimicrobial activity of the U-PEO:AgNP composite using agar diffusion assays and direct inoculation assays. The results showed that the U-PEO:AgNP composite exhibited significant antimicrobial activity against S. aureus, with an inhibition zone diameter of 20 mm. However, the antimicrobial efficacy against E. coli and C. albicans was weaker, suggesting that the concentration of AgNPs may have been insufficient to effectively inhibit these microorganisms.

Research Conclusions

This study successfully synthesized silver nanoparticles and U-PEO hybrid materials with antimicrobial potential and conducted comprehensive physicochemical characterization and antimicrobial evaluation. The results demonstrated that the U-PEO:AgNP composite exhibited good antimicrobial activity against S. aureus, particularly at a 1:1 ratio of AgNPs to U-PEO, where the material showed optimal antimicrobial performance. However, the weaker antimicrobial efficacy against E. coli and C. albicans indicates that future research needs to further optimize the concentration of AgNPs to enhance the material’s antimicrobial spectrum.

Research Highlights

  1. Innovative Design of Antimicrobial Coatings: This study is the first to combine silver nanoparticles with U-PEO hybrid materials to develop a hospital equipment coating with antimicrobial potential, offering a new solution for preventing nosocomial infections.
  2. Comprehensive Physicochemical Characterization: Using techniques such as FTIR, XRD, and TGA, the researchers thoroughly characterized the material’s structure, thermal stability, and wettability, ensuring its reliability and applicability.
  3. Evaluation of Antimicrobial Efficacy: Through MIC tests, agar diffusion assays, and direct inoculation assays, the researchers systematically assessed the antimicrobial efficacy of AgNPs and the composite material, providing a scientific basis for future applications.

Research Significance

This study provides new insights and methods for developing antimicrobial coatings for hospital equipment. By optimizing the concentration of AgNPs and the material formulation, future research could further enhance the antimicrobial efficacy of the composite, enabling its widespread use in clinical settings to reduce the incidence of nosocomial infections. Additionally, this study offers valuable references for the design and development of other antimicrobial materials.

This paper not only demonstrates the potential of silver nanoparticles in antimicrobial materials but also points the way for future research and applications. Through further research and optimization, this composite material could play a significant role in hospital equipment and other medical applications, providing a safer healthcare environment for patients and healthcare workers.