The effect of poly (lactic-co-glycolic) acid composition on the mechanical properties of electrospun fibrous mats

Biocompatibile nanofiber based membranes for high-efficiency filtration of nano-aerosols with low air resistance

Particulate matter (PMs) from combustion emissions (traffic, power plant, and industries) and the novel coronavirus (COVID-19) pandemic have recently enhanced the development of personal protective equipment against airborne pathogens to protect humans' respiratory system. However, most commercial face masks still cannot simultaneously achieve breathability and high filtration of PMs, bacteria, and viruses. This study used the electrospinning method with polyimide (PI) and polyethersulfone (PES) solutions to form a nanofiber membrane with low-pressure loss and high biocompatibility for high-efficiency bacteria, viruses, and nano-aerosol removal. Conclusively, the optimized nano-sized PI/PES membrane (0.1625 m²/g basis weight) exhibited conspicuous performance for the highest filtration efficiency towards PM from 50 to 500 nm (99.74 %), good filter quality of nano-aerosol (3.27 Pa^-1), exceptional interception ratio against 100-nm airborne COVID-19 (over 99 %), and non-toxic effect on the human body (107 % cell viability). The PI/PES nanofiber membrane required potential advantage to form a medical face mask because of its averaged 97 % BEF on Staphylococcus aureus filiation and ultra-low pressure loss of 0.98 Pa by referring ASTM F2101-01. The non-toxic PI/PES filters provide a new perspective on designing excellent performance for nano-aerosols from air pollution and airborne COVID-19 with easy and comfortable breathing under ultra-low air flow resistance.

Surface Functionalities of Polymers for Biomaterial Applications

Changes of a material biointerface allow for specialized cell signaling and diverse biological responses. Biomaterials incorporating immobilized bioactive ligands have been widely introduced and used for tissue engineering and regenerative medicine applications in order to develop biomaterials with improved functionality. Furthermore, a variety of physical and chemical techniques have been utilized to improve biomaterial functionality, particularly at the material interface. At the interface level, the interactions between materials and cells are described. The importance of surface features in cell function is then examined, with new strategies for surface modification being highlighted in detail.

Impact of the solvent composition on the structural and mechanical properties of customizable electrospun poly(vinylpyrrolidone) fiber mats

The performance of fibrous membrane composites fabricated via electrospinning is strongly influenced by the solution's properties, process variables and ambient conditions, although a precise mechanism for controlling the properties of the resulting composite has remained elusive. In this work, we focus on the fabrication of electrospun poly(vinylpyrrolidone) (PVP) fibers, by varying both the polymer concentration and the mixture of ethanol (EtOH) and dimethylformamide (DMF) used as solvent. The impact of the solvent composition on the structural properties is assessed by a combined experimental and theoretical approach, employing scanning electron microscopy (SEM), differential scanning calorimetry (DSC), rheology, Fourier-transform infrared spectroscopy (FTIR) and stress-strain curves obtained from tensile tests to characterize the fibrous membranes produced, and density functional theory (DFT) calculations to explain the solvent's affect on PVP crystallization. We establish a morphological phase diagram, and propose a possible mechanism based on the measured fiber diameter distribution, the viscoelastic properties of the precursor solution, the correlation between the functional groups and the mechanical properties, the thermal transitions and the degree of crystallinity. We also employ DFT calculations to model the polymer coverage at equilibrium of a PVP polymer chain in the presence of EtOH/DMF solvent mixtures to corroborate the crucial role their O or -OH groups play in achieving high PVP coverages and promoting the stability of the resulting fiber. These findings will be valuable to researchers interested in predicting, modulating, and controlling both a fiber's morphology and its concomitant physico-chemical properties.

Anti-solvent Precipitation Method Coupled Electrospinning Process to Produce Poorly Water-Soluble Drug-Loaded Orodispersible Films

Orodispersible films (ODFs) are more convenient for paediatric and geriatric patients to take as compared to conventional tablets and capsules. Electrospinning has recently been attempted to produce ODFs. This study investigated the feasibility of formulating poorly water-soluble drug into ODFs using electrospinning technology coupled with the anti-solvent precipitation method. Piroxicam (PX), a poorly water-soluble drug, was chosen as a model drug. Polyvinyl alcohol and polyvinylpyrrolidone were used as film forming polymers. PX microcrystals were prepared using poloxamer as the stabilizer with the anti-solvent precipitation method, and then loaded in ODFs through the electrospinning process. The obtained ODFs were characterized using a scanning electron microscope, X-ray powder diffraction and Fourier transform infrared spectroscopy with respect to the morphology, solid state and potential molecular interaction between the model drug and polymers. The mechanical property, disintegration and dissolution rate of the obtained ODF were evaluated using dynamic mechanical analysis, a customized method and USP2 apparatus. The results showed that PX microcrystals suspended in polymeric solutions could be readily electrospun into fibrous films, where the microcrystals scattered between the fibers. The electrospun fibrous film-based ODFs exhibited satisfactory mechanical behaviour, and fast disintegration upon the polymer selection. In the dissolution tests, almost 90% of PX was dissolved within 6 min from the ODFs, whereas 40% of PX dissolved from physical mixtures in 60 min. This study demonstrated that poorly water-soluble drugs could be formulated into ODFs with satisfactory quality attributes by combining micronization and the electrospinning process.