Benefits of Polyamide Nanofibrous Materials: Antibacterial Activity and Retention Ability for Staphylococcus Aureus

Abstract

Although nanomaterials are used in many fields, little is known about the fundamental interactions between nanomaterials and microorganisms. To test antimicrobial properties and retention ability, 13 electrospun polyamide (PA) nanomaterials with different morphology and functionalization with various concentrations of AgNO3 and chlorhexidine (CHX) were analyzed. Staphylococcus aureus CCM 4516 was used to verify the designed nanomaterials’ inhibition and permeability assays. All functionalized PAs suppressed bacterial growth, and the most effective antimicrobial nanomaterial was evaluated to be PA 12% with 4.0 wt% CHX (inhibition zones: 2.9 ± 0.2 mm; log10 suppression: 8.9 ± 0.0; inhibitory rate: 100.0%). Furthermore, the long-term stability of all functionalized PAs was tested. These nanomaterials can be stored at least nine months after their preparation without losing their antibacterial effect. A filtration apparatus was constructed for testing the retention of PAs. All of the PAs effectively retained the filtered bacteria with log10 removal of 3.3–6.8 and a retention rate of 96.7–100.0%. Surface density significantly influenced the retention efficiency of PAs (p ≤ 0.01), while the effect of fiber diameter was not confirmed (p ≥ 0.05). Due to their stability, retention, and antimicrobial properties, they can serve as a model for medical or filtration applications.

Antimicrobial Properties of Palladium and Platinum Nanoparticles: A New Tool for Combating Food-Borne Pathogens

“…Before and after cultivation, the suspensions were serially decimally diluted and compared by quantifying their CFU/mL. The three most diluted suspensions were applied in 20 µL droplets on a plate count agar (PCA, Oxoid, Cheshire, UK) in two parallels and incubated for 24 h at 37 • C. After the cultivation, the grown bacterial colonies were counted and quantified according to Lencova et al [27]. Four independent replicates were performed for each bacterial strain with specific metallic nanoparticles.…”

“…Besides the food industry, nanoparticles are nowadays broadly used in many other areas such as agriculture (nano-sized pesticides, herbicides, fungicides, fertilizers and sensors for crop cultivation and harvesting, pathogen detection and soil parameters [26]), medicine (nanomaterials functionalized with AgNO 3 and CHX [27], including nanofibersbased sensors for clinical monitoring [28]), biotechnology (mesoporous SiO 2 biosensors for enzyme immobilization [29]), cosmetics (nanotechnology-based sun creams, cosmetic powders, nanoemlusions and micelles [30]) and renewable energies (wind and geothermal power, energy storage, lighting and hydrogen fuel cells [31]).…”

Potential of Polyamide Nanofibers With Natamycin, Rosemary Extract, and Green Tea Extract in Active Food Packaging Development: Interactions With Food Pathogens and Assessment of Microbial Risks Elimination

“…The permeability assay was performed as described in Lencova et al (2021b) . Briefly, single-bacterial suspensions (3 ml, OD 1 McF) were filtered through a sterile (UV radiation, room temperature, 20 min) PA membrane (diameter 5 cm) placed in a sterile filtration apparatus (i) 70% ethanol, room temperature, 10 min; and then [(ii) UV radiation, room temperature, 30 min]; after the spontaneous filtration, the bacterial cells both in the filtered suspensions and in the obtained filtrates were quantified ( Lencova et al, 2021a ).…”

“…In addition to the mentioned biomaterials, synthetic polymer polyamide (PA) provides the mentioned advantages and is considered one of the suitable alternatives for packaging materials development ( Borzi et al, 2019 ; Tyuftin and Kerry, 2020 ), especially in connection with nanotechnologies. PA nanofibers prepared via electrospinning can be used for food packaging due to their suitable mechanical properties, such as mechanical resistance, strength under both dry and wet conditions, stability against chemical agents, flexibility, and excellent retention ability ( Lencova et al, 2021b ). At the same time, contrary to the biomaterials, PA is not degradable, can be used repeatedly, and thus provides environmental benefits ( Winnacker, 2017 ).…”

“…At the same time, contrary to the biomaterials, PA is not degradable, can be used repeatedly, and thus provides environmental benefits ( Winnacker, 2017 ). Despite such advantageous properties, PA itself is not antimicrobial and is not able to prolong foods shelf life by the prevention of microbial contamination ( Lencova et al, 2021a , b ).…”