Electrospun nanofiber a smart drug carriers: production methods, problems, solutions, and applications

Electrospinning is a fiber production technique that makes use of electric force to draw charged threads of polymeric solutions or polymer melts up to fiber diameters in the order of some hundred nanometers. In contrast, nanofibers produced by electrospinning are cylindrical structures with an outer diameter below 1000 nm, and an aspect ratio (the ratio between length and width) greater than 50 nm. This chapter aims to compile a comprehensive overview of electrospun nanofibers, including the detailed introduction of electrospun nanofibers as a drug carrier, their methods for production, drug loading, problems, solutions, and their detailed applications. We start with a detailed introduction to the traditional drug carriers generally used to carry active pharmaceutical ingredients (APIs), such as capsules shell, ointment bases, etc., followed by their route of administration to their systemic circulation. These traditional drug carriers have multiple disadvantages, such as selectivity, effectiveness, and/or safety of drug administration, requiring a high dose and more dosing frequency. This high dose and dosing frequency lead to major side effects. At the same time, APIs are also associated with many disadvantages, such as less bioavailability, shorter biological half-lives, low stability in biological fluids, and issues in passing through biological barriers. The scientific community has made much effort, especially biomedical scientists, to overcome these problems by developing effective and alternative drug carriers, such as liposomes, nanoparticles, micelles, and more. One of them is the electrospun nanofibers, which are potential drug carriers because they possess a high surface area-to-volume ratio for loading the drug molecules. In addition, a wide variety of polymers and materials can be used alone or in combination to form nanofibers. The ease of fiber functionalization, fiber deposition onto other substrates, structural properties, stability, and tunable chemical and physical properties make electrospunfibers extremely versatile to be used as drug carriers. We also highlight the most recent and relevant techniques used for their production and recent advancements in their applications as drug carriers in a systematic tabular form.