Antibacterial Nanofiber Membranes Research Articles

Alginate and chitosan-based polyamide 56 modified nanofiber membrane for highly effective capture of Escherichia coli: Antibacterial and cytotoxicity studies

In recent years, microbial fermentation has become a sustainable alternative to traditional petrochemical processes for producing biomass nylon 56 (i.e., PA56). This study is centered on creating a highly efficient antibacterial nanofiber membrane using bio-nylon 56 as the main material. The membrane was fabricated via a multi-step process involving sodium alginate, chitosan, and poly(hexamethylene biguanide) (PHMB). The PA56 nanofiber was chemically modified by sequential coupling with alginate (AG) and chitosan (CS), introducing a significant number of functional groups (-COOH and -NH2). This process resulted in the formation of PA56-AG and PA56-AG-CS nanofibers. Further modification with PHMB led to obtaining the PA56-AG-PHMB and PA56-AG-CS-PHMB antibacterial nanofiber membranes. The optimal preparation conditions for these membranes were determined, including the pH and concentration of AG, the molecular weight, pH, and concentration of CS, and the pH and concentration of PHMB. The PA56-based membranes demonstrated nearly 100 % antibacterial efficiency within a short time. However, the PA56-AG-PHMB membrane exhibited faster antibacterial rates and higher efficiency in repeated use compared to the PA56-AG-CS-PHMB membrane. The two-step coupling reaction in the preparation of PA56-AG-CS-PHMB may have reduced its surface accessibility to E. coli cells, resulting in slower bacterial attachment. Furthermore, the PA56-related membranes showed excellent biocompatibility, with a 100 % cell survival rate. Despite some limitations in reusability, biomass nylon PA56 stands out as an environmentally friendly material derived from renewable resources through microbial fermentation. It offers significant sustainability advantages over traditional petroleum-based nylons, as evidenced by the favorable cytotoxicity test results.

Fabrication and characterization of antibacterial nanofiber membranes modified with chitosan and imidazolidinyl urea for potential use in biological waste treatments

An ion exchange nanofiber membrane (AEA-COOH) was developed from polyacrylonitrile (PAN) nanofibers through chemical hydrolysis. It was further modified by grafting chitosan (CS) onto its surface, creating the AEA-COOH-CS membrane. Then, both membranes were covalently immobilized with imidazolidinyl urea (IU), resulting in AEA-COOH-IU and AEA-COOH-CS-IU membranes. This study analyzed their physical properties, antibacterial efficacy (AE), and reusability. Optimal conditions were identified: 50 kDa molecular weight of chitosan, pH 8 for IU modification, and 0.05 % IU concentration. The AEA-COOH-IU membrane achieved 96.15 % AE against Escherichia coli at an initial concentration of 2.0 × 107 CFU/mL, while the AEA-COOH-CS-IU membrane achieved 100 % AE. The AEA-COOH-CS-IU membrane maintained 95.04 % efficacy over 5 cycles, demonstrating superior durability. As a result, the AEA-COOH-CS-IU membrane has high potential for environmental applications such as water purification and wastewater treatment. Its robust antibacterial properties and reusability suggest a significant impact on ensuring cleaner water resources and prospective uses in the biomedical field, including medical device coatings and healthcare applications.

Preparation and Characterization of Electrospinning Gelatin Nanofiber Membranes Containing Carvacrol Nanoparticles

AbstractThe purpose of this study was to analyse the potential prospect of electrospinning gelatin nanofiber membranes containing carvacrol nanoparticles (G−Car−NPs−NF) as packaging material in food field. Sustained‐release antioxidant and antibacterial nanofiber membranes were prepared by incorporating the carvacrol nanoparticles (Car−NPs). Carvacrol (Car) was used to form nanoparticles with zein and sodium caseinate, and then electrospinning with gelatin‐based solution to form nanofiber membranes. The biological activities of composite nanofiber membranes were exhibited. The antioxidant capacity was characterized by the scavenging rate of 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) free radical. With the increase of the concentration of Car, the antioxidant capacity of G−Car−NPs−NF was gradually improved. In addition, G−Car−NPs−NF exhibited inhibitory effect on Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Candida albicans (C. albicans) and the inhibitory effect was positively correlated with the concentration. Moreover, the nanofiber membranes showed the slow‐release rate in vitro release and kept the appropriate concentration. These results were directly showed that G−Car−NPs−NF could be used as an effective packaging material for Car in food industry.

NIR light-triggered photodynamic antibacterial nanofiber membrane based on polycaprolactone and phthalocyanine derivative for biomedical applications.

Photodynamic therapy (PDT) is gaining recognition as a promising alternative method for the treatment of diverse biomedical applications. Toward this goal, we report herein the fabrication of an electrospun membrane utilizing polycaprolactone (PCL), and a phthalocyanine derivative, namely 1,4,8,11,15,22,25-octabutyloxy-29H,31-phthalocyanine (OBuPc). The designed OBuPc-PCL membrane aims to function as a dressing with the potential to facilitate the management of wound healing. The absorption and fluorescence studies of OBuPc have been examined by the steady-state and time-resolved absorption and fluorescence techniques. From direct detection of the weak emission of the singlet oxygen in the NIR region (at 1270 nm), the quantum yield of singlet oxygen was determined to be 0.05. The physiochemical properties of the nanofibers and membranes that were prepared were determined. The photo-activity of all the modified PCL nanofibers against Gram-positive S. aureus and Gram-negative E. coli was observed. The PCL/4.8 OBuPc nanofiber exhibited the highest effectiveness, primarily attributed to the enhanced effect of photosensitizer OBuPc as its concentration increased within the fibre. This resulted in S. aureus bacterial inhibition% of 62.5% ± 0.38 and 78.5% ± 0.49 after exposure to near infrared emission NIR at 630 nm for 15 minutes and 30 minutes, respectively. The inhibition of E. coli bacteria was observed to be 51.51% ± 0.49 and 62.44% ± 0.12% after exposure to near infrared (NIR) emission at a wavelength of 630 nm for durations of 15 minutes and 30 minutes, respectively. Additionally, it was observed that the membranes displayed dark bacterial inhibition. These unique features of the examined nanofibers render them a potential photodynamic antibacterial nanofiber membrane for efficient wound healing treatment and practical antibacterial uses.

Construction of Electrostatic Spinning Membranes Based on Conjugated Hemicyanine Derivatives for Photodynamic Antibacterial Application.

The preparation of efficient antibacterial membrane materials is one of the important strategies to fight against bacterial infection and alleviate drug resistance. Herein, hemicyanine derivatives with different chain lengths (C3, C6, and C10) that exhibit excellent photodynamic antibacterial activity were doped into spinnable polyvinyl alcohol solution (PVA, 8%) to obtain composite fiber membrane Cn/PVA (C3/PVA, C6/PVA, and C10/PVA) by a simple "one-pot" method using electrospinning technology. The antibacterial nanofiber membrane has a dense fiber structure which has a good interception effect, high thermal stability, and great biocompatibility. Importantly, Cn/PVA nanofibers could efficiently sensitize oxygen to generate reactive oxygen species (ROS), leading to high photokilling efficacy against drug-resistant bacteria. The variation of structure for hemicyanines causes the difference of Cn/PVA nanofibers in the effects of antibacterial performance, and it is found that C3/PVA and C10/PVA with three and ten carbons in the alkyl chain could kill more than 97% of ampicillin-resistant E. coli, which is much better than that of C6/PVA. Moreover, C3/PVA and C10/PVA exhibited killing efficiencies of 98.6 and 90.6% against MRSA, respectively. The construction of Cn/PVA composite fibers provides research ideas for the development of structure-dependent antimicrobial surface materials and is expected to be applied as superficial medical antibacterial protection materials.

Preparation and Characterization of a One-Step Electrospun Poly(Lactic Acid)/Wormwood Oil Antibacterial Nanofiber Membrane.

With the continuous improvement of the standard of living, people are increasingly inclined towards natural, green, and environmentally friendly products. Plant-based products that are safe, natural, non-toxic, and beneficial to human health are often more favored. Poly(lactic acid) (PLA) is a polymer obtained through lactate polymerization using renewable plant resources such as corn and has excellent biocompatibility and biodegradability. It is widely used in the field of food packaging. Wormwood oil (WO) is an oil extracted from the stems and leaves of Artemisia plants, and it has broad-spectrum antibacterial properties. In this article, through electrospinning technology, wormwood oil was directly incorporated into PLA, giving the PLA nanofiber membrane antioxidant and antibacterial functions. Various parameters such as voltage (11 KV, 13 KV, 15 KV), spinning solution concentration (8%, 10%, 12%), distance (15 cm, 17 cm, 19 cm), and feeding rate (0.4 mL/h, 0.5 mL/h, 0.6 mL/h) were explored, and the resulting spun fibers were characterized. Through SEM characterization, it was found that when the spinning voltage was 13 KV, the spinning solution concentration was 10%, the distance was 17 cm, and the feeding rate was 0.5 mL/h, the nanofiber membrane had a smooth morphology without bead formation, with an average diameter of 260 nm. The nanofiber membrane was characterized using FTIR, TG, and SEM, confirming the successful incorporation of artemisia essential oil into PLA. The prepared antimicrobial nanofilm was subjected to antimicrobial testing, and the results showed that as the concentration of the essential oil increased, the inhibition zones also increased. When wormwood oil concentration was 4%, the diameter of the inhibition zone for Staphylococcus aureus increased from 1.0 mm to 3.5 mm, while the diameter of the inhibition zone for Escherichia coli increased from 2.0 mm to 4.5 mm.

Research on the synthesis of MgO nanorods (MgONRs) with surface nano textures and its load on nanofiber membranes

The purpose of this research was to obtain the composite nanofiber membranes with efficient antibacterial property using synthetic magnesium-based antibacterial agents. Based on the antibacterial mechanism of MgO nanoparticles (MgONPs), the MgO nanorods (MgONRs) with surface nano textures (M-SNT) were designed to increase the effective contact area of MgONRs and bacteria, which achieved an excellent antibacterial property. The effect of the calcination temperature on the surface nano textures morphological and the antibacterial property of the M-SNT were systematically researched. When the calcination temperature reached 600 °C (M-SNT6), the surface nano textures of M-SNT6 was uniform and the antibacterial property was the most excellent, and the antibacterial rate was better than that of the commercial MgONPs (C-M). The highly-effective antibacterial nanofiber membranes were fabricated by loading 2.5 wt% M-SNT6 on polycaprolactone/polyvinyl pyrrolidone (PCL/PVP) substrates through electrospinning technology, which presented excellent antibacterial rate of 100% against E. coli.

Electrospun Ag‐dopedPA6multi‐stage structured nanofiber membrane with antibacterial property for oily particulate matters filtration

AbstractOily particulate matter pollution and bacteria pose a serious threat to human health and have drawn widespread attention. Herein, an Ag‐doped nylon 6 multi‐stage structured antibacterial nanofiber membrane (PA6&Ag MSNM) for effective air filtration of fine oily particulate matters was fabricated by adding a certain amount of tetrabutylammonium hexafluorophosphate (TBAHP) and silver nitrate (AgNO3) into PA6 solution via one‐step electrospinning. The fabricated PA6&Ag MSNM is composed of coarse trunk fibers and fine branching fibers, which exhibits high filtration efficiency for oily particulate matters and low pressure drop, with an average filtration efficiency of 99.92% for oily particles of 0.20 ~ 4.59 μm and a low pressure drop of 386 Pa. In addition, the fiber membranes possesses excellent antibacterial properties due to the doping of Ag. The prepared multi‐stage electrospun nanofiber membrane may provide a versatile strategy for designing new antibacterial air filtration materials, which would have broad application prospects.

Polyvinyl alcohol/chitosan nanofiber membranes loaded with oxygenated graphitic carbon nitride nanosheets for enhanced photocatalytic bacteriostasis

AbstractThe visible light catalytic antibacterial nanofiber membranes as a novel functional material were designed to solve the problem of bacterial infection and water pollution. In this work, oxygenated graphite carbon nitride nanosheets (O‐g‐C3N4) with 12% oxygen content were synthesized through thermal polycondensation followed by chemical oxidation. Exfoliation and dispersion of O‐g‐C3N4 were strongly enhanced compared to pristine g‐C3N4 due to rich hydrophilic carboxyl and hydroxyl groups. The amount of ROS generated by O‐g‐C3N4 was about 13.8% more than that of g‐C3N4. Then, the polyvinyl alcohol (PVA)/chitosan (CS)/O‐g‐C3N4 (PCO) composite nanofiber membranes were prepared by electrospinning. The contact angle of the PCO nanofiber membranes decreased from 55.0° ± 0.5 to 45.9° ± 0.2 along with the increased amount of O‐g‐C3N4, indicating the improvement of hydrophilicity. Meanwhile, the diameter of nanofibers increased from 148.0 ± 22.9 nm to 244.0 ± 52.3 nm with the loading ratio from 0% to 17%. The PCO nanofiber membranes exhibited significantly higher antibacterial activity compared to the blank nanofiber membranes and bare O‐g‐C3N4. The maximum diameter of the inhibition zone against Escherichia coli and Staphylococcus aureus could reach 26 ± 0.1 mm and 16 ± 0.2 mm, respectively. The inhibition rate against E. coli could reach 97% in 24 h under the irradiation of simulated sunlight. Based on reactive oxygen species (ROS) testing, zeta potential, and bacterial inhibition experiments, a possible synergistic mechanism was proposed. The electrostatic adsorption effect of PCO nanofiber membranes and ROS could effectively decompose the organic components of bacteria and destroy their structural integrity. The results indicated that the antibacterial PCO composite nanofiber membranes have wide application prospects in biomedical‐related fields.

Preparation and Properties of (Sc2O3-MgO)/Pcl/Pvp Electrospun Nanofiber Membranes for the Inhibition of Escherichia coli Infections.

Due to their high porosity, large specific surface area, and structural similarity with the extracellular matrix (ECM), electrospun nanofiber membranes are often endowed with the antibacterial properties for biomedical applications. The purpose of this study was to synthesize nano-structured Sc2O3-MgO by doping Sc3+, calcining at 600 °C, and then loading it onto the PCL/PVP substrates with electrospinning technology with the aim of developing new efficient antibacterial nanofiber membranes for tissue engineering. A scanning electron microscope (SEM) and energy dispersive X-ray spectrometer (EDS) were used to study the morphology of all formulations and analyze the types and contents of the elements, and an X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Fourier transform attenuated total reflection infrared spectroscopy (ATR-FTIR) were used for further analysis. The experimental results showed that the PCL/PVP (SMCV-2.0) nanofibers loaded with 2.0 wt% Sc2O3-MgO were smooth and homogeneous with an average diameter of 252.6 nm; the antibacterial test indicated that a low load concentration of 2.0 wt% Sc2O3-MgO in PCL/PVP (SMCV-2.0) showed a 100% antibacterial rate against Escherichia coli (E. coli).

A nanofiber Murray membrane with antibacterial properties for high efficiency oily particulate filtration

Particulate air pollution represented by PM2.5 is one of the biggest environmental challenges in the 21st century. Especially in 2020, the global outbreak of COVID-19 has brought new challenges to melt-blown filter materials, such as the attenuation of filtration efficiency with breathing, even no filtration effect for viruses as their smaller diameter, the sharp decline of filter efficiency after oily filtration cycle, and its limit in some explosive occasions. Here, using the diameter difference of polystyrene (PS), polyvinylidene fluoride (PVDF) and nylon 6(PA6) fibers, we report a multistage structure nanofiber membrane (PS/PVDF/PA6&Ag MSNMs) with high efficiency, low resistance and antibacterial effect by constructing gradient pore structure and introducing silver nanoparticles (Ag NPs), overcoming the above defects. The average filtration efficiency of PS/PVDF/PA6&Ag MSNMs for diisooctyl sebacate (DEHS) monodisperse particles from 0.2 μm to 4.9 μm was 99.88%, and the pressure drop was only 128 Pa. After repeated circulation for 100 times, the filtration efficiency and pressure drop remained stable. Above all, the antibacterial nanofiber membrane with high efficiency and low resistance has been preliminarily constructed, the future research will further focus on the performance after circulation.

Rapid Ferroelectric-Photoexcited Bacteria-Killing of Bi4Ti3O12/Ti3C2T x Nanofiber Membranes.

The online version contains supplementary material available at 10.1007/s42765-022-00234-8.

Preparation and properties of polylactic acid (PLA) antibacterial nanofiber membrane with Ag@TP composite antibacterial agent

This paper presented the composite antibacterial agent of nano-silver (Ag) and tea polyphenol (TP) by bioreduction method. Then polylactic acid (PLA) nanofiber membranes with different antibacterial content were prepared by electrostatic spinning method. The morphologies, structural characteristics and properties of electrostatic spun fiber membranes were investigated by scanning electron microscope (SEM), infrared spectroscopy (FTIR), electronic single fiber strength machine and flat colony counting method. The results showed that Ag@TP was loaded with silver nanoparticles with uniform particle size distribution. When the content of Ag@TP of electrospun fiber was less than 2.0%, the diameter of electrostatic spinning fiber was uniformly distributed and had smooth surface. It could be seen from the FTIR spectrum that Ag@TP and PLA were well compounded through valence bonds. As the content of antibacterial agent increased, the elongation at break of the fiber membrane first decreased and then increased. While the breaking strength was found to first decrease, then increase and decrease again. The water contact angle of the fiber membrane was gradually decreased with the increase of the antibacterial agent content. When the amount of Ag@TP was added 2.0%, the relative antibacterial rate of the electrospun fiber membrane to E.coli and S.aureus was as high as 95%, indicating an excellent antibacterial effect.

Fabrication and research of Mg(OH)2/PCL/PVP nanofiber membranes loaded by antibacterial and biosafe Mg(OH)2 nanoparticles

In order to fabricate antibacterial nanofiber membranes for tissue engineering field, the oxidative damage of magnesium hydroxide nanoparticles (Mg(OH)2 NPs) against the model system of Escherichia coli (E. coli) was researched by measuring the oxidative stress response, oxidative stress products and glucose metabolism. The toxicity of Mg(OH)2 NPs to a normal biological system was evaluated in vivo through the acute oral toxicity, blood physiological and serum biochemical markers and acute skin irritation, indicating that the Mg(OH)2 NPs exhibited great biosafety. The Mg(OH)2 NPs with antibacterial property and biosafety were loaded on PCL/PVP nanofiber substrates through electrospinning technology to fabricate the Mg(OH)2/PCL/PVP nanofiber membranes. The results of characterization and antibacterial test showed that the Mg(OH)2/PCL/PVP nanofiber membranes with 8.0 wt% Mg(OH)2 NPs present excellent antibacterial rate of 100% against E. coli that the Mg(OH)2 NPs can be physically and evenly loaded on nanofiber substrates.

Ti-MOF-based biosafety materials for efficient and long-life disinfection via synergistic photodynamic and photothermal effects

Pathogenic bacterial infection is severely threatening public health globally. The multi-modal antibacterial nanoplatforms could significantly improve the antibacterial efficiency. Here, we report a metal(Ti)-organic framework (MOF) derived nanocarbon (C-Ti-MOF) as a biosafety material for synergistic sterilization of pathogenic bacteria via efficient photodynamic catalysis and robust photothermal effects. The C-Ti-MOF consists of abundant TiO2 nanodots embedded in graphitic carbon frameworks. Under visible light irradiation, TiO2 nanodots can catalyze H2O2 and O2 to produce superoxide anion (•O2–) and singlet oxygen (1O2), respectively. Meanwhile, under near-infrared irradiation (NIR), C-Ti-MOF can generate massive heat to destroy bacterial membranes. Systematic antibacterial experiments reveal that the C-Ti-MOF nanoagents have a long-lasting and nearly 100% bactericidal ratio at an extremely low dose (0.16 mg/mL), which is much better than the state-of-the-art TiO2 (Commercial TiO2 (P25), 0.64 mg/mL). Furthermore, the C-Ti-MOF can be electrospun into an antibacterial nanofiber membrane via mixing with polymeric matrix for treating bacteria-contaminated wastewater, and the membranes possess integrated antibacterial activity and excellent biocompatibility. Our study demonstrates a promising Ti-MOF-based biosafety material for efficient and long-life disinfection, which may stimulate new research in MOF-related biological applications in various disciplines ranging from water decontaminations to nanotherapeutics.

Preparation and characterization of biodegradable electrospinning PHBV/PBAT/TiO2 antibacterial nanofiber membranes

To reduce the environmental pollution caused by medical protective materials, such as masks and protective clothing, biodegradable antibacterial materials have received more and more attention in recent years. In this study, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(butylene-adipate-co-terephthalate) (PBAT) were electrospun together and then treated with nano-TiO2 to develop and evaluate a biodegradable, antibacterial nanofiber membrane for medical protective fabric. The SEM images displayed that the nanofiber membrane with a mass fraction of 13 and a mass ratio of 50:50 PHBV/PBAT had the smallest diameter and the best morphology of all samples. In addition, the mechanical properties test and water contact angle test results demonstrated that the PBAT/PHBV composite nanofiber membrane had better mechanical properties and hydrophobicity without compromising its fundamental structure than pure PHBV. The addition of TiO2 nanoparticles decreased the fiber diameter of this nanofiber membrane. When the TiO2 concentration was 1.0 wt%, the average fiber diameter was 367 nm, which might approach the sub-micron level. Meanwhile, the presence of TiO2 reduced adhesion between fibers of the PBAT/PHBV membrane, resulting in a more uniform fiber distribution. Additionally, the elongation at the break of the PHBV/PBAT/TiO2 nanofiber membrane with 1.0 wt% TiO2 was raised from (135 ± 5)% to (203 ± 2)%. The PHBV/PBAT/TiO2 nanofiber membrane containing 1.0 wt% TiO2 inhibited Escherichia coli and Staphylococcus aureus, and its antibacterial rate was over 98%. In this research, we successfully prepared composite materials that were both biodegradable and antibacterial, which can be applied in the field of medical protection. It can promote the development of protective textile materials in the direction of functionalization and degradation.

Electrospun PVA/gelatin based nanofiber membranes with synergistic antibacterial performance

Synergistic antimicrobial action as a new strategy against various bacteria is attractive in the development of novel antibacterial materials. Based on this, the combination of peppermint oil (PO) and amoxicillin (AM) was constructed in order to achieve a synergistic antimicrobial effect with small amount of antibiotic addition. Then the synergistic antimicrobial PO and AM were introduced into polyvinyl alcohol/gelatin matrix to fabricate excellent antibacterial nanofiber membranes by electrospinning technique. Their morphologies and compositions of the prepared nanofiber membranes were investigated. The antibacterial ability and the antibacterial mechanism of the fabricated nanofiber membranes were determined. The co-incorporation of PO and AM into the nanofiber membranes showed strong antimicrobial activity with good cytocompatibility on intestinal epithelioid cell line 6. Therefore, this combination of PO and AM loaded nanofiber membrane as antibacterial material with synergistic antibacterial mechanism is very promising in the various antibacterial and bacterial inhibition applications.

Characteristics of MgO/PCL/PVP antibacterial nanofiber membranes produced by electrospinning technology

In this work, the antibacterial nanofibers of MgO/PCL/PVP (MCV) used for tissue engineering materials were prepared using PCL/PVP (CV) as nanofiber substrates and magnesium oxide nanoparticles (MgONPs) as antibacterial agents by electrospinning technology. The suitable CV substrates with excellent microscopic morphology and small average diameter of 208.5 ± 74.9 nm were prepared by electrospinning the mixture of PCL and PVP with the mass ratio of 1: 1. The MCV antibacterial nanofibers were successfully fabricated by loading MgONPs onto the suitable CV substrates by electrospinning process. In addition, the characterizations including scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR) indicated that 3.0 wt% MgONPs were physically and evenly loaded onto the CV substrates (MCV-3.0), which presented an excellent antibacterial rate of 100% against Escherichia coli (E. coli).

Antibacterial efficacy of poly(hexamethylene biguanide) immobilized on chitosan/dye-modified nanofiber membranes

This study aimed to develop a novel electrospun polyacrylonitrile (PAN) nanofiber membrane with the enhanced antibacterial property. The PAN nanofiber membrane was first subjected to alkaline hydrolysis treatment, and the treated membrane was subsequently grafted with chitosan (CS) to obtain a CS-modified nanofiber membrane (P-COOH-CS). The modified membrane was then coupled with different dye molecules to form P-COOH-CS-Dye membranes. Lastly, poly(hexamethylene biguanide) hydrochloride (PHMB) was immobilized on the modified membrane to produce P-COOH-CS-Dye-PHMB. Physical characterization studies were conducted on all the synthesized nanofiber membranes. The antibacterial efficacies of nanofiber membranes prepared under different synthesis conditions were evaluated systematically. Under the optimum synthesis conditions, P-COOH-CS-Dye-PHMB was highly effective in disinfecting a high concentration of Escherichia coli, with an antibacterial efficacy of approximately 100%. Additionally, the P-COOH-CS-Dye-PHMB exhibited an outstanding wash durability as its antibacterial efficacy was only reduced in the range of 5%–7% even after 5 repeated cycles of treatment. Overall, the experimental results of this study suggested that the P-COOH-CS-Dye-PHMB is a promising antibacterial nanofiber membrane that can be adopted in the food, pharmaceutical, and textile industries.

Fabrication of bio-based polyamide 56 and antibacterial nanofiber membrane from cadaverine

A green bioprocess for the fabrication of nanofiber membranes from the biomaterial polyamide 56 (PA56) via electrospinning was proposed. Cadaverine, as the precursor of PA56, was first produced from recombinant Escherichia coli using the whole-cell biotransformation of lysine. PA56 was then fabricated by mixing adipic acid with purified cadaverine obtained from solvent extraction and distillation. The thermal properties of the fabricated PA56 are as follows: a melting point of 250 °C, a crystallization point of 220 °C, and a degradation temperature of 410 °C. A PA56 nanofiber membrane (PAM) was further prepared via electrospinning. Dyed membranes (P-Dye) were obtained by the reaction of Reactive Red 141 dye with the amino group of PAM. Poly-(hexamethylene biguanide) (PHMB) was attached to the P-Dye to create P-Dye-PHMB. On the other hand, PAM with alginate, used to facilitate PHMB attachment (P-Alg-PHMB), was compared with P-Dye-PHMB in terms of antibacterial activity against pathogenic strains of E. coli and Pseudomonas putida. P-Alg-PHMB showed excellent antibacterial efficiency for E. coli (97%) and P. putida (100%). The proposed bioprocess can be used to fabricate novel membranes for biomedical applications and functional textiles.