Application of Solution Blow Spinning for Rapid Fabrication of Gelatin/Nylon 66 Nanofibrous Film

Preparation of amphiphilic polyquaternium nanofiber films with antibacterial activity via environmentally friendly microfluidic-blow-spinning for green food packaging applications

Green food packaging plays an important role in environmental protection and sustainable development. Therefore, it is advisable to employ low-energy consumption manufacturing techniques, select environmentally friendly materials, and focus on cost-effectiveness with high production yields during the production process. In this study, an amphiphilic polyquaternium called PBzCl was proposed and synthesized by free radical polymerization of cost-efficient quaternary ammonium salts and methacrylate monomers. Then, biodegradable PCL and PVP were used to rapidly prepare the PBzCl@PCL/PVP nanofiber films via environmentally friendly microfluidic-blow-spinning (MBS). The best antibacterial effect was observed at a PBzCl loading concentration of 13.5%, and the PBzCl@PCL/PVP nanofiber films had 91% and 100% antibacterial rates against Escherichia coli and Staphylococcus aureus, respectively. Besides, the loading of PBzCl improved the water stability of the PCL/PVP nanofiber films, and the films also showed excellent biocompatibility. Overall, PBzCl@PCL/PVP nanofibre films have promising food packaging potential.

Automatic in situ short-distance deposition of PLGA/PLLA composite nanofibrous membranes for personalized wound dressings

Improving the mechanical properties of wound dressings and achieving personalized automatic real-time in situ deposition are important for accelerating wound management and repair. In this study, we report a self-designed automatic in situ deposition device based on solution blow spinning (SBS) to prepare poly(lactic-co-glycolic acid) (PLGA) and poly-L-lactic acid (PLLA) composite (PLGA/PLLA) nanofibrous membranes for wound dressing at a short distance. Polymer solution and in situ deposition conditions, including air pressure, spinning distance, solvent extrusion rate, and spinning rate, were optimized using orthogonal experiments and characterized via dynamic mechanical analysis. The microscopic morphology and physical properties of the prepared PLGA/PLLA composite nanofibrous membranes show that their strength, adhesion, water vapor transmission rate (WVTR), water retention, water absorption, degradation, and other properties were sufficient for wound-dressing applications. To investigate the possibility of a biomedical wound-dressing material, tannic acid (TA) was incorporated into the PLGA/PLLA composite nanofibrous membranes. The resultant PLGA/PLLA/TA composite nanofibrous membranes exhibited good biocompatibility and exceptional antibacterial properties against both Escherichia coli and Staphylococcus aureus. A pilot animal study illustrated the potential of this in situ deposition of PLGA/PLLA/TA composite nanofibrous membranes across multiple applications in wound healing/repair by reducing wound scar tissue formation and fibroblast overactivation.

PCL/gelatin nanofibers embedded with doxorubicin-loaded mesoporous silica nanoparticles/silver nanoparticles as an antibacterial and anti-melanoma cancer

Melanoma cancer wound healing is critical and complex and poses a significant challenge to researchers. Drug resistance, adverse side effects, and inefficient localization of chemotherapeutic drugs limit common treatment strategies in melanoma cancer. Using drug delivery nanostructures with low side effects and high efficiency, besides having antibacterial and antiseptic properties, can effectively repair the damage caused by the disease. To this end, this study aimed to develop a drug delivery nanosystem based on doxorubicin (DOX)-loaded amine-functionalized mesoporous silica nanoparticles (MSNs), linked with green synthesized silver nanoparticles (AgNPs). Characterization methods including microscopic methods and X-ray diffraction (XRD) confirmed the synthesis and functionalization of the well-dispersed nanoparticles with nanosized and uniform structures. The poly(ε-caprolactone) (PCL) nanofibers as a strong scaffold were produced by the blow spinning method and DOX-loaded nanoparticles were blow spun on PCL nanofibers along with gelatin solution. The resulting nanosystem including nanofibers and nanoparticles (NFs/NPS) showed a fine loading percent with a proper release profile of DOX and AgNPs and low hemolysis activity. Moreover, besides preventing infection by AgNPs, the DOX-loaded NFs/NPs could effectively destroy melanoma cancer cells. The attachment of normal cells to the nanoparticles-loaded nanofibers scaffold revealed the possibility of healing wounds caused by melanoma cancer.

The Relationships between the Structure and Properties of PA56 and PA66 and Their Fibers

Bio-based polymers can reduce dependence on nonrenewable petrochemical resources and will be beneficial for future sustainable developments due to their low carbon footprint. In this work, the feasibility of bio-based polyamide 56 (PA56) substituting petroleum-based PA66 is systematically investigated. The crystallization, melting, and decomposition temperature of PA56 were all lower than that of PA66. PA56 formed a γ crystal type with larger grain size and took a longer amount of time to complete the crystallization process since its crystallization rate was lower than that of PA66. Compared with PA66, PA56 exhibited a higher tensile strength of 71.3 ± 1.9 MPa and specific strength of 64.8 ± 2.0 MPa but lower notched impact strength. More importantly, the limited oxygen index and vertical combustion measurement results indicated that the flame retardancy of PA56 was better than PA66, and the LOI values and the UL94 result of PA56 were 27.6% ± 0.9% and V-2. It is worth noting that the PA56 fiber had superior biodegradability compared to the PA66 fiber. PA56 showed significant biodegradation from the eighth week, whereas PA66 remained clean until the sixteenth week (without obvious biodegradation taking place). Eventually, PA56 did not show significant differences compared to PA66 in terms of thermal and mechanical properties. However, PA56 had great advantages in flame retardancy and biodegradability, indicating that the bio-based PA56 could potentially replace petroleum-based PA66 in many fields.

The preparation, resources, applications, and future trends of nanofibers in active food packaging: a review

Active packaging is a novel strategy for maintaining the shelf life of products and ensuring their safety, freshness, and integrity that has emerged with the consumer demand for safer, healthier, and higher quality food. Nanofibers have received a lot of attention for the application in active food packaging due to their high specific surface area, high porosity, and high loading capacity of active substances. Three common methods (electrospinning, solution blow spinning, and centrifugal spinning) for the preparation of nanofibers in active food packaging and their influencing parameters are presented, and advantages and disadvantages between these methods are compared. The main natural and synthetic polymeric substrate materials for the nanofiber preparation are discussed; and the application of nanofibers in active packaging is elaborated. The current limitations and future trends are also discussed. There have been many studies on the preparation of nanofibers using substrate materials from different sources for active food packaging. However, most of these studies are still in the laboratory research stage. Solving the issues of preparation efficiency and cost of nanofibers is the key to their application in commercial food packaging.

Facile microfluidic fabrication and characterization of ethyl cellulose/PVP films with neatly arranged fibers

Much attention and endeavor have been paid to developing biocompatible food packaging films. Here, ethyl cellulose (EC) and polyvinylpyrrolidone (PVP) were fabricated into films through a facile method, microfluidic spinning. Morphology observations showed that the fibers were neatly arranged with an average diameter of 1-4 μm. FTIR and X-ray diffraction analysis suggested the existence of good compatibility and interaction between EC and PVP. Thermogravimetric analysis demonstrated that PVP ameliorates the thermal properties; moreover, the tensile properties were improved, with tensile strength (TS) and Young's modulus up to 11.10 ± 1.04 MPa and 350.16 ± 45.46 MPa, respectively. The optimal formula was EC/PVP (2:3), of which the film displayed an enhanced TS of 4.61 ± 1.15 MPa and a modified water contact angle of 61.8 ± 4.4°, showing fine tensile and hydrophilic performance. This study provides a facile and green film fabrication method promising to be used for food wrapping.

Characterization of glycosylated gelatin/pullulan nanofibers fabricated by multi-fluid mixing solution blow spinning

In this work, multi-fluid mixing solution blow spinning was applied to develop gelatin/pullulan composite nanofibers, and then the nanofibers were glycated to enhance the physical properties. The results show that the grafting degree of the nanofibers increased significantly from 17.5 % to 36.0 % as the glycation time increased, and the morphology results indicated that 72 h of glycation did not destroy the structure of the nanofibers. FTIR results show that the glycation consumed the the-NH₂ groups, cleaved sugar units of polysaccharide, and affected the secondary structure of the protein. The glycation enhanced the thermal stability and improved the rigidity of the nanofibers. Besides, after 120 h of glycation, the water contact angle of nanofibers increased from 0° to 79.1°, and the water vapor transmission rates decreased from 12.49 to 8.97 g mm/m² h kPa, indicating the enhanced hydrophobicity and barrier properties. In addition, the glycation improved the water stability of the nanofibers, which increased the applicability of the gelatin/pullulan nanofibers in food packaging. The present work provides a green and efficient method for improving the physical properties of gelatin/pullulan nanofibers.

Electrospun Polymer Nanofibers with Antimicrobial Activity

Nowadays, nanofibers with antimicrobial activity are of great importance due to the widespread antibiotic resistance of many pathogens. Electrospinning is a versatile method of producing ultrathin fibers with desired properties, and this technique can be optimized by controlling parameters such as solution/melt viscosity, feeding rate, and electric field. High viscosity and slow feeding rate cause blockage of the spinneret, while low viscosity and high feeding rate result in fiber discontinuities or droplet formation. The electric field must be properly set because high field strength shortens the solidification time of the fluid streams, while low field strength is unable to form the Taylor cone. Environmental conditions, temperature, and humidity also affect electrospinning. In recent years, significant advances have been made in the development of electrospinning methods and the engineering of electrospun nanofibers for various applications. This review discusses the current research on the use of electrospinning to fabricate composite polymer fibers with antimicrobial properties by incorporating well-defined antimicrobial nanoparticles (silver, titanium dioxide, zinc dioxide, copper oxide, etc.), encapsulating classical therapeutic agents (antibiotics), plant-based bioactive agents (crude extracts, essential oils), and pure compounds (antimicrobial peptides, photosensitizers) in polymer nanofibers with controlled release and anti-degradation protection. The analyzed works prove that the electrospinning process is an effective strategy for the formation of antimicrobial fibers for the biomedicine, pharmacy, and food industry.

Polycaprolactone/polyvinyl pyrrolidone nanofibers developed by solution blow spinning for encapsulation of chlorogenic acid

Study on the application of nanofibers in food active packaging has been a research hotspot in recent years. In this work, the solution blow spinning (SBS) was applied to rapidly fabricate the polycaprolactone (PCL), polyvinyl pyrrolidone (PVP), and PCL/PVP nanofibrous films to encapsulate chlorogenic acid (CGA). All the films showed uniform and smooth nanofibers, and the FTIR and XRD proved the success of mixed spinning of PCL and PVP. With the increase of PVP content, the thermal stability of the PCL/PVP nanofibrous films improved. The PCL/PVP (4:1) film possessed better mechanical properties than PCL and PVP films because of the stronger fiber-fiber interactions. The addition of PCL endowed the hydrophobic surfaces to the PCL/PVP films, and the PCL/PVP films had better water vapor barrier ability. The PCL/PVP (4:1) film exhibited the best long-term continuous release of CGA during 72 h. The PVP nanofibrous film exhibited no inhibition against S. aureus and E. coli due to the low encapsulation efficiency, but the PCL and PCL/PVP films exhibited good antimicrobial activity. The above results suggested that the nanofibrous films developed by SBS possessed the promising prospects in food packaging.