Electrospinning: a fascinating fiber fabrication technique.

Electrospinning is a highly versatile method to process solutions or melts, mainly of polymers, into continuous fibers with diameters ranging from a few micrometers to a few nanometers. This technique is applicable to virtually every soluble or fusible polymer. The polymers can be chemically modified and can also be tailored with additives ranging from simple carbon-black particles to complex species such as enzymes, viruses, and bacteria. Electrospinning appears to be straightforward, but is a rather intricate process that depends on a multitude of molecular, process, and technical parameters. The method provides access to entirely new materials, which may have complex chemical structures. Electrospinning is not only a focus of intense academic investigation; the technique is already being applied in many technological areas.

Electrospinning: A Fascinating Method for the Preparation of Ultrathin Fibers

Electrospinning: Applications in drug delivery and tissue engineering

Electrospinning is a versatile and viable technique for generating ultrathin fibers. Remarkable progress has been made with regard to the development of electrospinning methods and engineering of electrospun nanofibers to suit or enable various applications. We aim to provide a comprehensive overview of electrospinning, including the principle, methods, materials, and applications. We begin with a brief introduction to the early history of electrospinning, followed by discussion of its principle and typical apparatus. We then discuss its renaissance over the past two decades as a powerful technology for the production of nanofibers with diversified compositions, structures, and properties. Afterward, we discuss the applications of electrospun nanofibers, including their use as "smart" mats, filtration membranes, catalytic supports, energy harvesting/conversion/storage components, and photonic and electronic devices, as well as biomedical scaffolds. We highlight the most relevant and recent advances related to the applications of electrospun nanofibers by focusing on the most representative examples. We also offer perspectives on the challenges, opportunities, and new directions for future development. At the end, we discuss approaches to the scale-up production of electrospun nanofibers and briefly discuss various types of commercial products based on electrospun nanofibers that have found widespread use in our everyday life.

Electrospinning and Electrospun Nanofibers: Methods, Materials, and Applications

Recent developments of zinc oxide based photocatalyst in water treatment technology: A review

It is highly desirable, although very challenging, to develop self-healable materials exhibiting both high efficiency in self-healing and excellent mechanical properties at ambient conditions. Herein, a novel Cu(II)-dimethylglyoxime-urethane-complex-based polyurethane elastomer (Cu-DOU-CPU) with synergetic triple dynamic bonds is developed. Cu-DOU-CPU demonstrates the highest reported mechanical performance for self-healing elastomers at room temperature, with a tensile strength and toughness up to 14.8 MPa and 87.0 MJ m-3 , respectively. Meanwhile, the Cu-DOU-CPU spontaneously self-heals at room temperature with an instant recovered tensile strength of 1.84 MPa and a continuously increased strength up to 13.8 MPa, surpassing the original strength of all other counterparts. Density functional theory calculations reveal that the coordination of Cu(II) plays a critical role in accelerating the reversible dissociation of dimethylglyoxime-urethane, which is important to the excellent performance of the self-healing elastomer. Application of this technology is demonstrated by a self-healable and stretchable circuit constructed from Cu-DOU-CPU.

A Highly Efficient Self-Healing Elastomer with Unprecedented Mechanical Properties.

This article describes an electrospinning process to fabricate double-layered ultrafine fibers. A bioabsorbable polymer, Polycaprolactone (PCL), was used as the outer layer or the shell and two medically pure drugs, Resveratrol (RT, a kind of antioxidant) and Gentamycin Sulfate (GS, an antibiotic), were used as the inner layers or the cores. Morphology and microstructure of the ultrafine fibers were characterized by scanning electron microscope (SEM) and transmission electron microscopy (TEM), whereas mechanical performance of them was understood through tensile test. In vitro degradation rates of the nanofibrous membranes were determined by measuring their weight loss when immersed in pH 7.4 phosphate-buffered saline (PBS) mixed with certain amount of Pseudomonas lipase for a maximum of 7 days. The drug release behaviors of the RT and GS were measured using a high performance liquid chromatography (HPLC) and ultraviolet-visible (UV-vis) spectroscopy, respectively. It has been found that the drug solutions without any fiber-forming additive could be encapsulated in the PCL ultrafine fibers, although they alone cannot be made into a fiber form. Beads on the fiber surface influenced the tensile behavior of the ultrafine fibers remarkably. When the core solvent was miscible with the shell solvent, higher drug concentration decreased the bead formation and thus favored the mechanical performance. The situation, however, became different if the two solvents were immiscible with each other. The degradation rate was closely related to hydrophilicity of the drugs in the cores. Higher hydrophilicity apparently led to faster degradation. The release profiles of the RT and GS exhibited a sustained release characteristic, with no burst release phenomenon.

Encapsulating drugs in biodegradable ultrafine fibers through co-axial electrospinning.

Chitosan, a naturally occurring polysaccharide with abundant resources, has been extensively exploited for various biomedical applications, typically as wound dressings owing to its unique biocompatibility, good biodegradability and excellent antibacterial properties. In this work, composite nanofibrous membranes of chitosan (CS) and silk fibroin (SF) were successfully fabricated by electrospinning. The morphology of electrospun blend nanofibers was observed by scanning electron microscopy (SEM) and the fiber diameters decreased with the increasing percentage of chitosan. Further, the mechanical test illustrated that the addition of silk fibroin enhanced the mechanical properties of CS/SF nanofibers. The antibacterial activities against Escherichia coli (Gram negative) and Staphylococcus aureus (Gram positive) were evaluated by the turbidity measurement method; and results suggest that the antibacterial effect of composite nanofibers varied on the type of bacteria. Furthermore, the biocompatibility of murine fibroblast on as-prepared nanofibrous membranes was investigated by hematoxylin and eosin (H&E) staining and MTT assays in vitro, and the membranes were found to promote the cell attachment and proliferation. These results suggest that as-prepared chitosan/silk fibroin (CS/SF) composite nanofibrous membranes could be a promising candidate for wound healing applications.

https://www.mdpi.com/1422-0067/11/9/3529/pdf

Fabrication of chitosan/silk fibroin composite nanofibers for wound-dressing applications.

Intermolecular interactions in electrospun collagen–chitosan complex nanofibers

Surface fuctionalization plays a crucial role in developing efficient nanoparticulate drug-delivery systems by improving their therapeutic efficacy and minimizing adverse effects. Here we propose a simple layer-by-layer self-assembly technique capable of constructing mesoporous silica nanoparticles (MSNs) into a pH-responsive drug delivery system with enhanced efficacy and biocompatibility. In this system, biocompatible polyelectrolyte multilayers of alginate/chitosan were assembled on MSN’s surface to achieve pH-responsive nanocarriers. The functionalized MSNs exhibited improved blood compatibility over the bare MSNs in terms of low hemolytic and cytotoxic activity against human red blood cells. As a proof-of-concept, the anticancer drug doxorubicin (DOX) was loaded into nanocarriers to evaluate their use for the pH-responsive drug release both in vitro and in vivo. The DOX release from nanocarriers was pH dependent, and the release rate was much faster at lower pH than that of at higher pH. The in vitro...

Effect of pH-Responsive Alginate/Chitosan Multilayers Coating on Delivery Efficiency, Cellular Uptake and Biodistribution of Mesoporous Silica Nanoparticles Based Nanocarriers

Chuanglong He

Papers

A Highly Efficient Self-Healing Elastomer with Unprecedented Mechanical Properties.

Encapsulating drugs in biodegradable ultrafine fibers through co-axial electrospinning.

Fabrication of chitosan/silk fibroin composite nanofibers for wound-dressing applications.

Intermolecular interactions in electrospun collagen–chitosan complex nanofibers

Effect of pH-Responsive Alginate/Chitosan Multilayers Coating on Delivery Efficiency, Cellular Uptake and Biodistribution of Mesoporous Silica Nanoparticles Based Nanocarriers