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Bacterial Biofilms on Polyamide Nanofibers: Factors Influencing Biofilm Formation and Evaluation
Simona Lencova1, Viviana Svarcova1, Hana Stiborova1
1Faculty of Food and Biochemical Technology, Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Technicka 3, Prague 6 16628, Czech Republic.
Abstract:
Electrospun polyamide (PA) nanofibers have great potential for medical applications (in dermatology as antimicrobial compound carriers or surgical sutures). However, little is known about microbial colonization on these materials. Suitable methods need to be chosen and optimized for the analysis of biofilms formed on nanofibers and the influence of their morphology on biofilm formation. We analyzed 11 PA nanomaterials, both nonfunctionalized and functionalized with AgNO3, and tested the formation of a biofilm by clinically relevant bacteria (Escherichia coli CCM 4517, Staphylococcus aureus CCM 3953, and Staphylococcus epidermidis CCM 4418). By four different methods, it was confirmed that all of these bacteria attached to the PAs and formed biofilms; however, it was found that the selected method can influence the outcomes. For studying biofilms formed by the selected bacteria, scanning electron microscopy, resazurin staining, and colony-forming unit enumeration provided appropriate and comparable results. The values obtained by crystal violet (CV) staining were misleading due to the binding of the CV dye to the PA structure. In addition, the effect of nanofiber morphology parameters (fiber diameter and air permeability) and AgNO3 functionalization significantly influenced biofilm maturation. Furthermore, the correlations between air permeability and surface density and fiber diameter were revealed. Based on the statistical analysis, fiber diameter was confirmed as a crucial factor influencing biofilm formation (p ≤ 0.01). The functionalization of PAs with AgNO3 (from 0.1 wt %) effectively suppressed biofilm formation. The PA functionalized with a concentration of 0.1 wt % AgNO3 influenced the biofilm equally as nonfunctionalized PA 8% 2 g/m2. Therefore, biofilm formation could be affected by the above-mentioned morphology parameters, and ultimately, the risk of infections from contaminated medical devices could be reduced.
Insights
Biofilm formation on polyamide nanofibers is influenced by fiber diameter and silver nitrate functionalization. Proper analysis methods are crucial for accurate results, aiding in reducing medical device infections.
Area of Science:
- Biomaterials Science
- Microbiology
- Nanotechnology
Background:
- Electrospun polyamide (PA) nanofibers show promise for medical uses, but their interaction with microbes, specifically biofilm formation, is not well understood.
- Optimizing methods to analyze biofilms on nanofibers is essential for evaluating their clinical applicability.
Purpose of the Study:
- To investigate microbial colonization and biofilm formation on various PA nanofibers.
- To assess the impact of nanofiber morphology and silver nitrate (AgNO3) functionalization on biofilm development.
- To identify reliable methods for biofilm analysis on PA nanomaterials.
Main Methods:
- Analysis of 11 PA nanomaterials, including nonfunctionalized and AgNO3-functionalized variants.
- Testing biofilm formation using clinically relevant bacteria: Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermidis.
- Employing four distinct methods for biofilm quantification: scanning electron microscopy (SEM), resazurin staining, colony-forming unit (CFU) enumeration, and crystal violet (CV) staining.
Main Results:
- All tested bacteria formed biofilms on PA nanofibers, with method selection significantly impacting results.
- SEM, resazurin staining, and CFU enumeration provided reliable and comparable biofilm data.
- Crystal violet staining yielded misleading results due to dye binding with the PA structure.
- Nanofiber morphology (fiber diameter, air permeability) and AgNO3 functionalization significantly affected biofilm maturation.
- Fiber diameter was identified as a critical factor (p ≤ 0.01) influencing biofilm formation.
- AgNO3 functionalization (≥ 0.1 wt %) effectively inhibited biofilm formation.
Conclusions:
- The choice of biofilm analysis method is critical for accurate assessment on PA nanofibers.
- Nanofiber morphology and silver nitrate functionalization are key factors controlling biofilm formation.
- Optimizing these parameters can reduce the risk of infections associated with medical devices.
