Fabrication of Hybrid Nanofibers from Biopolymers and Poly (Vinyl Alcohol)/Poly (ε-Caprolactone) for Wound Dressing Applications

The management of chronic wounds is challenging. The factors that impede wound healing include malnutrition, diseases (such as diabetes, cancer), and bacterial infection. Most of the presently utilized wound dressing materials suffer from severe limitations, including poor antibacterial and mechanical properties. Wound dressings formulated from the combination of biopolymers and synthetic polymers (i.e., poly (vinyl alcohol) or poly (ε-caprolactone) display interesting properties, including good biocompatibility, improved biodegradation, good mechanical properties and antimicrobial effects, promote tissue regeneration, etc. Formulation of these wound dressings via electrospinning technique is cost-effective, useful for uniform and continuous nanofibers with controllable pore structure, high porosity, excellent swelling capacity, good gaseous exchange, excellent cellular adhesion, and show a good capability to provide moisture and warmth environment for the accelerated wound healing process. Based on the above-mentioned outstanding properties of nanofibers and the unique properties of hybrid wound dressings prepared from poly (vinyl alcohol) and poly (ε-caprolactone), this review reports the in vitro and in vivo outcomes of the reported hybrid nanofibers.

Polyacrylonitrile/CoCl2 Nanofibers Based Humidity Sensor for Human Breath and Ambient Humidity Monitoring

A novel humidity sensor was constructed using the hybrid nanofibers of polyacrylonitrile/CoCl2 (PAN/CoCl2), which were fabricated by electrospinning. Scanning electron microscopy (SEM) image demonstrated that the diameter of PAN/CoCl2 nanofibers ranged from 100 - 500 nm. Energy-dispersive X-ray spectrometer (EDS) analysis confirmed that Co and Cl elements were homogeneously dispersed on the PAN nanofibers. CoCl2 on the surface of PAN nanofibers play a dual function in humidity sensing performances. First, CoCl2 serves as an indicator, which can change the color of nanofibers from blue to white-pink as the relative humidity changed from 11 to 98 %, to realize the colorimetric sensing. Second, CoCl2 could remarkably improve the electric sensing performance. As a result, the PAN/CoCl2 nanofibers offered much enhanced response currents compared to the pristine PAN nanofibers, as the humidity changed from RH 11 to 98 %. In addition, the PAN/CoCl2 nanofibers based humidity sensor was employed to monitor human breath and the ambient humidity, which demonstrated the excellent sensitivity of this humidity sensor. Therefore, we believe that the highly sensitive and simply designed PAN/CoCl2 humidity sensor is a promising candidate for various applications in the field of humidity monitoring.