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Updated: Dec 20, 2025
Evaluation of Antimicrobial Activities of Nanoparticles and Nanostructured Surfaces In Vitro
Published on: April 21, 2023
Vancomycin-loaded nanoparticles against vancomycin intermediate and methicillin resistant Staphylococcus aureus
Alice Simon1, Marina Lucianeli Araujo Moreira1, Isabela Francisca de Jesus Borges Costa2
1Laboratório de Tecnologia Industrial Farmacêutica, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro - UFRJ, CCS, Lss20, Ilha do Fundão, 21941-590, Rio de Janeiro, RJ, Brazil.
Abstract:
Bacterial infections represent one of the leading causes of mortality in the world. Among causative pathogens, S. aureus is prominently known as the underlying cause of many multidrug resistant infections that are often treated with the first-line choice antibiotic vancomycin (VCM). Loading antibiotics into polymeric nanoparticles (Np) displays promise as an alternative method to deliver therapy due to the greater access and accumulation of the antibiotic at the site of the infection as well as reducing toxicity, irritation and degradation. The aim of this work was to prepare, characterize and evaluate VCM-loaded nanoparticles (VNp) for use against S. aureus strains. Moreover, conjugation of Nps with holo-transferrin (h-Tf) was investigated as an approach for improving targeted drug delivery. VNp were prepared by double emulsion solvent evaporation method using PLGA and PVA or DMAB as surfactants. The particles were characterized for size distribution, Zeta Potential, morphology by transmission electron microscopy, encapsulation yield and protein conjugation efficiency. Process yield and drug loading were also investigated along with an in vitro evaluation of VNp antimicrobial effects against S. aureus strains. Results showed that Np were spontaneously formed with a mean diameter lower than 300 nm in a narrow size distribution that presented a spherical shape. The bioconjugation with h-Tf did not appear to increase the antimicrobial effect of VNp. However, non-bioconjugated Np presented a minimal inhibitory concentration lower than free VCM against a MRSA (Methicillin-resistant S. aureus) strain, and slightly higher against a VISA (VCM intermediate S. aureus) strain. VNp without h-Tf showed potential to assist in the development of new therapies against S. aureus infections.
Insights
Vancomycin-loaded nanoparticles show potential for treating multidrug-resistant Staphylococcus aureus infections. Non-bioconjugated nanoparticles demonstrated improved efficacy against MRSA strains compared to free vancomycin.
Area of Science:
- Biotechnology
- Materials Science
- Infectious Diseases
Background:
- Bacterial infections, particularly those caused by multidrug-resistant Staphylococcus aureus, pose a significant global health threat.
- Vancomycin (VCM) is a primary antibiotic for treating S. aureus infections, but resistance is a growing concern.
- Polymeric nanoparticles (Np) offer a promising drug delivery system to enhance antibiotic efficacy and reduce toxicity.
Purpose of the Study:
- To prepare, characterize, and evaluate vancomycin-loaded nanoparticles (VNp) for combating S. aureus.
- To investigate the potential of holo-transferrin (h-Tf) conjugation for targeted drug delivery of VNp.
- To assess the in vitro antimicrobial activity of VNp against S. aureus strains.
Main Methods:
- VNp were synthesized using a double emulsion solvent evaporation method with PLGA and PVA or DMAB surfactants.
- Nanoparticles were characterized for size, Zeta potential, morphology (TEM), encapsulation yield, and protein conjugation efficiency.
- In vitro antimicrobial activity was evaluated against Methicillin-resistant S. aureus (MRSA) and Vancomycin-intermediate S. aureus (VISA) strains.
Main Results:
- Spherical nanoparticles with a mean diameter below 300 nm and narrow size distribution were successfully prepared.
- Holo-transferrin bioconjugation did not significantly enhance the antimicrobial effect of the nanoparticles.
- Non-bioconjugated VNp exhibited a lower minimum inhibitory concentration than free vancomycin against MRSA and a slightly higher concentration against VISA.
Conclusions:
- Non-bioconjugated vancomycin-loaded nanoparticles show promise as an alternative therapeutic strategy against S. aureus infections.
- This nanoparticle formulation may help overcome challenges associated with conventional vancomycin therapy.
- Further research into VNp could lead to improved treatments for challenging bacterial infections.
