Electrospinning has been recognized as a unique technology that can produce nonwoven fibrous mat with fiber diameter ranging from tens of nanometers to micro so its application is very extended, for instance in filters, sensors, medical application and etc. The most important requirement for the medical applications of electrospun nanowebs is its biodegradability and its biocompatibility in a specific environment, as well as non-toxicity of its degradation products. Aliphatic polyesters such as poly lactide acid(PLA), poly(lactide-co-glycolic)(PLGA),and poly(?-caprolactone)(PCL)are among the few synthetic polymers that meet these requirements and have been used in tissue engineering. However because of low hydrophilicity, cell affinity of synthetic polymer is poor. oly (? -caprolactone) has good mechanical properties but its use as a polymeric scaffold is limited because it is hydrophobic. In this study hydrophilicity of PCL fibers was improved by adding low molecular weight poly ethylene glycol (PEG) to the electrospinning solution. Poly (caprolactone) (PCL) with Mw=80000 and poly (ethylene glycol)(PEG)with Mw =4000, as well as methylene chloride (MC)and dimethyformamide (DMF) as solvent were used to electro-spin the polymer blend. Three blend solution concentrations (12, 14, and16)% each with (80/20 and 60/40) of PCL/PEG were electrospun. Pure PCL mat with a 10.5% solution concentration was also electrospun for comparison. SEM, FTIR, XRD and Contact Angle were used for the analysis. FTIR spectra showed that there were no interaction between PCL and PEG. The surface energy of Nanofibrous mat was tested by measuring the contact angle. The contact angle of pure PCL electrospun scaffold was about 118.2, indicating surface tension. For PCL/PEG samples contact angle was almost zero, indicating that the addition of small amount of hydrophilic PEG to PCL decrease the surface energy leading to an efficient spreading of cell solution on the scaffold. After conditioning for 24 hr,(T=25±2 o C and 75%relative humidity) the moisture content of the samples were measured. With increase in PEG content humidity content was increased. The adhesion behavior of cells on the PCL/PEG matrix surfaces was evaluated using CHO cells as a model cell. According to the SEM images, adhesion and proliferation on the surface of electrospun PCL/PEG mats as compared with pure PCL improved to a maximum and decreased as a result of farther PEG addition
