Application of the Electrospinning Technique in Electrochemical Biosensors: An Overview

Electrospinning is a cost-effective and flexible technology for producing nanofibers with large specific surface areas, functionalized surfaces, and stable structures. In recent years, electrospun nanofibers have attracted more and more attention in electrochemical biosensors due to their excellent morphological and structural properties. This review outlines the principle of electrospinning technology. The strategies of producing nanofibers with different diameters, morphologies, and structures are discussed to understand the regulation rules of nanofiber morphology and structure. The application of electrospun nanofibers in electrochemical biosensors is reviewed in detail. In addition, we look towards the future prospects of electrospinning technology and the challenge of scale production.

A review of graphene quantum dots and their potential biomedical applications

Today, nanobiotechnology is a pioneering technology in biomedicine. Every day, new nanomaterials are synthesized with elevated physiochemical properties for better diagnosis and treatment of diseases. One advancing class of materials is the Graphene family. Among different kinds of graphene derivatives, graphene quantum dots (GQDs) show fantastic optical, electrical, and electrochemical features originating from their unique quantum confinement effect. Due to the distinct properties of GQD, including large surface-to-volume ratio, low cytotoxicity, and easy functionalization, this nanomaterial has gone popular in biomedical field. Herein, a short overview of different strategies developed for GQD synthesis and functionalization is discussed. In the following, the most recent progress of GQD based nanomaterials in different biomedical fields, including bio-imaging, drug/gene delivery, antimicrobial, tissue engineering, and biosensors, are reviewed.

Pivotal role of electrospun nanofibers in microfluidic diagnostic systems - a review

Recently, the usage of electrospinning technology for the fabrication of fine fibers with a good deal of variation in morphology and structure has drawn the attention of many researchers around the world. These fibers have found their way in the many fields of science including medical diagnosis, tissue engineering, drug delivery, replica molding, solar cells, catalysts, energy conversion and storage, physical and chemical sensors and other applications. Among all applications, biosensing with the aim of rapid and sensitive biomarker detection is an area that warrants attention. Electrospun nanofibrous membranes enjoy numerous factors which benefit them to be used as potential candidates in biosensing platforms. Some of these factors include a high surface to volume ratio, analogous scale compared to bioactive molecules and relatively defect-free properties of nanofibers (NFs). In this review, we focused on the recent advances in electrospun nanofibrous membrane-based micro-analytical devices with an application as diagnostic systems. Hence, a study on the electrospun nanofiber usage in lab-on-a-chip and paper-based point-of-care devices, with an opening introduction to biosensors, nanofibers, the electrospinning method, and microfluidics as the principles of the intended subject, is provided. It is anticipated that the given examples in this paper will provide sufficient evidence for the potential of electrospun NFs for being used as a substrate in the commercial fabrication of highly sensitive and selective biosensors.

Highly efficient detection of cancer-derived exosomes using modified core-shell electrospun nanofibers as a capture substrate and antibody immobilized-graphene quantum dots as a signaling agent

In the past few years graphene quantum dots (GQDs) have been used as a signaling agent for medical diagnosis. They can be modified and labeled with different macromolecules to give them potential to be attached to a specific target. Herein GQDs were labeled with an antibody which is specific for cancer-derived exosomes, isolated from blood serum by using a specialized PCL-gelatin core-shell NFM. This membrane showed excellent sensitivity for isolating exosomes from a complex mixture such as serum, and the GQD-antibody complex detected the isolated exosomes with great sensitivity. The final results allow this method to be considered as one that can be used to quantify the concentration of a desired analyte in a mixture.

A promising approach toward efficient isolation of the exosomes by core-shell PCL-gelatin electrospun nanofibers

Exosomes as cell-derived vesicles are promising biomarkers for noninvasive and early detection of different types of cancer. However, a straightforward and cost-effective technique for isolation of exosomes in routine clinical settings is still challenging. Herein, we present for the first time, a novel coaxial nanofiber structure for the exosome isolation from body fluids with high efficiency. Coaxial nanofiber structure is composed of polycaprolactone polymer as core and a thin layer of gelatin (below 10 nm) as the shell. The thermo-sensitive thin layer of gelatin can efficiently release the captured exosome by specific antibody namely, CD63, whenever its temperature raised to the physiological temperature of 37 °C. Moreover, the thin layer of gelatin induces less contamination to separated exosomes. The interconnected micro-pores of electrospun nanofibrous membrane insurances large surface area for immobilization of specific antibody for efficient exosome capturing. The efficacy of exosome isolation is determined by direct ELISA and compared with ultracentrifugation technique. For the exosome isolation, it was observed that over 87% of exosomes existed in the culture medium can be effectively isolated by coaxial electrospun nanofibers with the average thickness of 50 µm. Therefore, this promising technique can be substituted for the traditional techniques for exosome isolation which are mostly suffering from low efficacy, high cost, and troublesome process.