Novel DNA/Polyethyleneoxide (PEO) electrospun fibers were obtained from aqueous solution. Key solution properties related to electrospinning: conductivity, surface tension and viscosity were determined. The ionic conductivity of the solution increased significantly with the addition of DNA and only slightly with increasing amounts of PEO; the surface tension decreased with the addition of PEO; the viscosity increased with the addition of either DNA or PEO. It was found that solutions containing both DNA and PEO had ideal properties for electrospinning. The use of these solutions resulted in the formation of ultrafine fibrous mats with fiber diameters of 50-250 nm. It was also found that the average diameter of electrospun fibers decreased with decreased feed rate, increased tip-to-collector distance and increase in the potential employed during electrospinning. (c) 2007 Elsevier Ltd. All rights reserved.