The art and technology of electrospinning has generated considerable interest in the field of tissue engineering. Studies describing various aspects and applications of the electrospinning process and patent filings for intellectual property concerning this rapidly evolving technology have undergone a remarkable expansion from 1995 to 2007. Relevant to the biological sciences and the tissue engineering fields, this technology can be used to process a variety of native [1-3] and synthetic polymers [4-6] into highly porous tissue engineering scaffolds composed of nano-scale to micron-scale diameter fibers [7], a size-scale that approaches the fiber diameters observed in the native extracellular matrix.
The physical, biochemical, and biological properties of electrospun materials can be regulated at several sites in the production process. For many polymers, physical properties, including fiber diameter, fiber alignment and pore dimension [8,9], can be regulated simply by controlling the composition of the electrospinning solvent, the air gap distance, accelerating voltage, mandrel properties and the concentration, and/or degree of chain entanglements (viscosity) present in the starting solutions [7,10]. The ability to directly regulate the physical properties of an electrospun material through the manipulation of these fundamental variables affords considerable control over the process.
The flexibility inherent to the electrospinning process makes this fabrication strategy adaptive to a variety of different fields of use. Notably, in biological applications, electrospinning shows great potential as a gateway to the development and fabrication of physiologically relevant tissue engineering scaffolds [11,12], hemostatic agents, wound care products [13], and solid phase drug and peptide delivery platforms [14]. To date, electrospinning has not penetrated to any great extent into product lines designed for diagnostic and research applications, fields of use closely allied to the more biologically applied field of tissue engineering.
Electrospun materials, by nature, exhibit an extensive surface area. The sequential deposition of the discreet, individual fibers that are formed in this process also results in a unique and complex interconnected network of pores. In this study we report that it is possible to exploit these characteristic to fabricate solid phase platforms designed for protein (i.e. Western blot) and/or nucleic acid detection (i.e. Northern blot and Southern blot). In conventional protein and nucleic acid blotting experiments, a charged sheet of nitrocellulose or nylon is used as a solid phase support [15,16]. Proteins or nucleic acids may be directly applied or transferred from a separation media, usually a polyacrylamide or agar based gel, to the solid substrate. This transfer may be affected by a vacuum, electric field or through capillary action, resulting in the binding of the protein or nucleic acid sample to the solid phase substrate. These binding events are mediated by non-specific interactions that are directly dependent upon the charge characteristics of the protein or nucleic acid of interest and the blotting platform and the surface area available for binding. Once the protein or nucleic acid of interest has been bound to the solid substrate, the sheets are blocked to reduce/eliminate non-specific binding events [17] and probed by any number of different methods to detect specific protein antigens or nucleic acid sequences [15,18-21]. These same methods can be used in conjunction with electrospinning technology to develop novel platforms for the detection of proteins and nucleic acids.
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