Characterization of Polydioxanone in Near-Field Electrospinning

Mechanical characterization and neutrophil NETs response of a novel hybrid geometry polydioxanone near-field electrospun scaffold

Near-field electrospinning (NFES) is a direct fiber writing sub-technique derived from traditional electrospinning (TES) by reducing the air gap distance to the magnitude of millimeters. In this paper, we demonstrate a NFES device designed from a commercial 3D printer to semi-stably write polydioxanone (PDO) microfibers. The print head was then programmed to translate in a stacking grid pattern, which resulted in a scaffold with highly aligned grid fibers that were intercalated with low density, random fibers. As the switching process can be considered random, increasing the grid size results in both a lower density of fibers in the center of each grid cell as well as a lower density of 'rebar-like' stacked fibers. These scaffolds resulted in tailorable as well as greater surface pore sizes as given by scanning electron micrographs and 3D permeability as indicated by fluorescent microsphere filtration compared to TES scaffolds of the same fiber diameter. Furthermore, ultimate tensile strength, percent elongation, yield stress, yield elongation, and Young's modulus were all tailorable compared to the static TES scaffold characterization. Lastly, the innate immune response of neutrophil extracellular traps was attenuated on NFES scaffolds compared to TES scaffolds. These results suggest that this novel NFES scaffold architecture of PDO can be highly tailored as a function of programming for a variety of biomedical and tissue engineering applications.

Near-Field Electrospinning and Melt Electrowriting of Biomedical Polymers-Progress and Limitations

Near-field electrospinning (NFES) and melt electrowriting (MEW) are the process of extruding a fiber due to the force exerted by an electric field and collecting the fiber before bending instabilities occur. When paired with precise relative motion between the polymer source and the collector, a fiber can be directly written as dictated by preprogrammed geometry. As a result, this precise fiber control results in another dimension of scaffold tailorability for biomedical applications. In this review, biomedically relevant polymers that to date have manufactured fibers by NFES/MEW are explored and the present limitations in direct fiber writing of standardization in published setup details, fiber write throughput, and increased ease in the creation of complex scaffold geometries are discussed.

Using Solution Electrowriting to Control the Properties of Tubular Fibrous Conduits

Multiple additive manufacturing techniques have been developed in recent years to produce structures with tunable physical, chemical, and mechanical properties and defined architecture. Solution electrospinning, although an older and more established technique, normally cannot achieve the pattern resolution and tunability of these newer manufacturing techniques. In this study, we present solution electrowriting as a method to produce fibrous conduits from various polymers with tunable patterns, dimensions, and scaffold porosity. We demonstrate the importance of solvent selection during solution electrowriting and discuss how solvent polarity and volatility can be exploited to controllably alter the structure of the resulting scaffolds. The technique can be readily implemented with equipment for conventional electrospinning and offers versatility, control, and customization that is uncommon in the solution electrospinning field.

3D Printing as a Promising Tool in Personalized Medicine

Personalized medicine has the potential to revolutionize the healthcare sector, its goal being to tailor medication to a particular individual by taking into consideration the physiology, drug response, and genetic profile of that individual. There are many technologies emerging to cause this paradigm shift from the conventional "one size fits all" to personalized medicine, the major one being three-dimensional (3D) printing. 3D printing involves the establishment of a three-dimensional object, in a layer upon layer manner using various computer software. 3D printing can be used to construct a wide variety of pharmaceutical dosage forms varying in shape, release profile, and drug combination. The major technological platforms of 3D printing researched on in the pharmaceutical sector include inkjet printing, binder jetting, fused filament fabrication, selective laser sintering, stereolithography, and pressure-assisted microsyringe. A possible future application of this technology could be in a clinical setting, where prescriptions could be dispensed based on individual needs. This manuscript points out the various 3D printing technologies and their applications in research for fabricating pharmaceutical products, along with their pros and cons. It also presents its potential in personalized medicine by individualizing the dose, release profiles, and incorporating multiple drugs in a polypill. An insight on how it tends to various populations is also provided. An approach of how it can be used in a clinical setting is also highlighted. Also, various challenges faced are pointed out, which must be overcome for the success of this technology in personalized medicine.