Electrospun nanofibers for 3-D cancer models, diagnostics, and therapy

As one of the leading causes of global mortality, cancer has prompted extensive research and development to advance efficacious drug discovery, sustained drug delivery and improved sensitivity in diagnosis. Towards these applications, nanofibers synthesized by electrospinning have exhibited great clinical potential as a biomimetic tumor microenvironment model for drug screening, a controllable platform for localized, prolonged drug release for cancer therapy, and a highly sensitive cancer diagnostic tool for capture and isolation of circulating tumor cells in the bloodstream and for detection of cancer-associated biomarkers. This review provides an overview of applied nanofiber design with focus on versatile electrospinning fabrication techniques. The influence of topographical, physical, and biochemical properties on the function of nanofiber assemblies is discussed, as well as current and foreseeable barriers to the clinical translation of applied nanofibers in the field of oncology.

Recent Advances in Functional Materials through Cellulose Nanofiber Templating

Advanced templating techniques have enabled delicate control of both nano- and microscale structures and have helped thrust functional materials into the forefront of society. Cellulose nanomaterials are derived from natural polymers and show promise as a templating source for advanced materials. Use of cellulose nanomaterials in templating combines nanoscale property control with sustainability, an attribute often lacking in other templating techniques. Use of cellulose nanofibers for templating has shown great promise in recent years, but previous reviews on cellulose nanomaterial templating techniques have not provided extensive analysis of cellulose nanofiber templating. Cellulose nanofibers display several unique properties, including mechanical strength, porosity, high water retention, high surface functionality, and an entangled fibrous network, all of which can dictate distinctive aspects in the final templated materials. Many applications exploit the unique aspects of templating with cellulose nanofibers that help control the final properties of the material, including, but not limited to, applications in catalysis, batteries, supercapacitors, electrodes, building materials, biomaterials, and membranes. A detailed analysis on the use of cellulose nanofibers templating is provided, addressing specifically how careful selection of templating mechanisms and methodologies, combined toward goal applications, can be used to directly benefit chosen applications in advanced functional materials.

Methods and applications of nanocellulose loaded with inorganic nanomaterials: A review

Nanocellulose obtained from natural renewable resources has attracted enormous interests owing to its unique morphological characteristics, excellent mechanical strength, biocompatibility and biodegradability for a variety of applications in many fields. The template structure, high specific surface area, and active surface groups make it feasible to conduct surface modification and accommodate various nano-structured materials via physical or chemical deposition. The review presented herein focuses on the methodologies of loading different nano-structured materials on nanocellulose, including metals, nanocarbons, oxides, mineral salt, quantum dots and nonmetallic elements; and further describes the applications of nanocellulose composites in the fields of catalysis, optical electronic devices, biomedicine, sensors, composite reinforcement, photoswitching, flame retardancy, and oil/water separation.

Free-standing three-dimensional hollow bacterial cellulose structures with controlled geometry via patterned superhydrophobic-hydrophilic surfaces

Bacteria can produce cellulose, one of the most abundant biopolymer on earth, and emerge as an interesting candidate to fabricate advanced materials. Cellulose produced by Komagataeibacter Xylinus, a bacterial strain, is a pure water insoluble biopolymer, without hemicellulose or lignin. Bacterial cellulose (BC) exhibits a nanofibrous porous network microstructure with high strength, low density and high biocompatibility and it has been proposed as cell scaffold and wound healing material. The formation of three dimensional (3D) cellulose self-standing structures is not simple. It either involves complex multi-step synthetic procedures or uses chemical methods to dissolve cellulose and remold it. Here we present an in situ single-step method to produce self-standing 3D-BC structures with controllable wall thickness, size and geometry in a reproducible manner. Parameters such as hydrophobicity of the surfaces, volume of the inoculum and time of culture define the resulting 3D-BC structures. Hollow spheres and convex domes can be easily obtained by changing the surface wettability. The potential of these structures as a 3D cell scaffold is exemplified supporting the growth of mouse embryonic stem cells within a hollow spherical BC structure, indicating its biocompatibility and future prospective.

High-throughput and high-yield fabrication of uniaxially-aligned chitosan-based nanofibers by centrifugal electrospinning

The inability to produce large quantities of nanofibers has been a primary obstacle in advancement and commercialization of electrospinning technologies, especially when aligned nanofibers are desired. Here, we present a high-throughput centrifugal electrospinning (HTP-CES) system capable of producing a large number of highly-aligned nanofiber samples with high-yield and tunable diameters. The versatility of the design was revealed when bead-less nanofibers were produced from copolymer chitosan/polycaprolactone (C-PCL) solutions despite variations in polymer blend composition or spinneret needle gauge. Compared to conventional electrospinning techniques, fibers spun with the HTP-CES not only exhibited superior alignment, but also better diameter uniformity. Nanofiber alignment was quantified using Fast Fourier Transform (FFT) analysis. In addition, a concave correlation between the needle diameter and resultant fiber diameter was identified. This system can be easily scaled up for industrial production of highly-aligned nanofibers with tunable diameters that can potentially meet the requirements for various engineering and biomedical applications.