Electrochemical characterization of PVA/SA nanofibers obtained by electrospinning processing

Electrospinning Novel Sodium Alginate/MXene Nanofiber Membranes for Effective Adsorption of Methylene Blue

Understanding how to develop highly efficient and robust adsorbents for the removal of organic dyes in wastewater is crucial in the face of the rapid development of industrialization. Herein, d-Ti₃C₂T_x nanosheets (MXene) were combined with sodium alginate (SA), followed by electrospinning and successive Ca²⁺-mediated crosslinking, giving rise to a series of SA/MXene nanofiber membranes (NMs). The effects of the MXene content of the NMs on the adsorption performance for methylene blue (MB) were investigated systemically. Under the optimum MXene content of 0.74 wt.%, SA/MXene NMs possessed an MB adsorption capacity of 440 mg/g, which is much higher than SA/MXene beads with the same MXene content, pristine MXene, or electrospinning SA NMs. Furthermore, the optimum SA/MXene NMs showed excellent reusability. After the adsorbent was reused ten times, both the MB adsorption capacity and removal rate could remain at 95% of the levels found in the fresh samples, which indicates that the electrospinning technique has great potential for developing biomass-based adsorbents with high efficiency.

In vitro and in vivo evaluation of nanofibre mats containing Calendula officinalis extract as a wound dressing

OBJECTIVE

The present study aims to create Calendula officinalis-loaded nanofibre-based wound dressing materials to enhance the wound healing process. Calendula officinalis is an annual herb native to the Mediterranean region. It is antipyretic, antifungal, antioedema, antidiabetic, anti-inflammatory (wound, oral and pharyngeal mucosa), antispasmodic, treats chronic ocular surface diseases, acts as a stimulant and a diaphoretic. It is also used in the prevention of acute dermatitis, and in the treatment of gastrointestinal ulcers, wounds and burns.

METHOD

Electrospinning is an effective method for creating nano- and microfibres for biomedical applications. Calendula officinalis (CA) of various concentrations 5%, 10% and 15%)-loaded polyvinyl alcohol (PVA)/sodium alginate (SAlg) nanofibre mats were successfully produced via blend electrospinning. Nanofibre mats were evaluated using: scanning electron microscopy (SEM); Fourier transform infrared spectroscopy (FTIR) analysis; gel content; water vapour transmission rate (WVTR); swelling ratio; in vitro drug release studies; viability evaluation (cell culture and MTT assay); and an in vivo study using male Wistar rats. Rats were divided into three groups (n=3). In each group, rats were inflicted with five full-thickness wounds on the back and were treated with sterile gauze (control), PVA/SAlg nanofibre dressing (CA-free control), PVA/SAlg/CA5%, PVA/SAlg/CA10%, and PVA/SAlg/CA15% nanofibre dressing.

RESULTS

Results showed that the obtained fibres were smooth with no surface aggregates, indicating complete incorporation of Calendula officinalis. The release of Calendula officinalis from loaded PVA/SAlg fibre mats in the first four hours was burst released and then was constant. PVA/SAlg and PVA/SAlg/CA nanofibres were not toxic to L929 mouse fibroblasts and supported cell attachment and proliferation. The results of the in vivo study showed that the PVA/SAlg/CA10% nanofibre dressing had a higher full-thickness wound healing closure rate compared with the control group on days seven, 14 and 21 after treatment.

CONCLUSION

The results of this evaluation showed that PVA/SAlg/CA nanofibrous mats could be a candidate as an effective wound dressing; however, the percentage of CA in this compound needs further investigation.

Mass-Production and Characterizations of Polyvinyl Alcohol/Sodium Alginate/Graphene Porous Nanofiber Membranes Using Needleless Dynamic Linear Electrospinning

The aim of this study was to investigate the feasibility of large-scale preparation of porous polyvinyl alcohol/sodium alginate/graphene (Gr) (Gr-AP) nanofiber membranes using a copper wire needleless dynamic linear electrode electrospinning machine. Furthermore, the effects of Gr concentrations (0, 0.0375, 0.075, 0.25, 0.5, and 0.75 wt.%) on the morphology, electrical, hydrophilicity and thermal properties were evaluated. Results indicate that the dynamic linear electrospun Gr-AP membranes have a high yield of 1.25 g/h and are composed of porous finer nanofibers with a diameter of 141 ± 31 nm. Gr improved the morphology, homogeneity, hydrophobicity and thermal stability of Gr-AP nanofiber membranes. The critical conductive threshold is 0.075 wt.% for Gr, which provides the nanofiber membranes with an even distribution of diameter, an optimal conductivity, good hydrophilicity, appropriate specific surface area and optimal thermal stability. Therefore, needleless dynamic linear electrospinning is beneficial to produce high quality Gr-AP porous nanofiber membranes, and the optimal parameters can be used in artificial nerve conduits and serve as a valuable reference for mass production of nanofiber membranes.