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176 PROCEEDINGS OF INTERNATIONAL SCIENTIFIC CONFERENCE ON APPLIED BIOTECHNOLOGYElectrospinning processThe solution 4 was put into a 5 ml syringe attached to a metal needle that connected to a high voltage of 20 kV. The feeding rate of solution was 1 mL/h. The distance from the needle to the collector was set at 15 cm. Produced nanofibers containing 12% of capsaicin were dried by a vacuum drying machine at 50oC for 12 hours to completely remove the solvents [19]. 2.3. Characterization of the nanofibersMorphological analysisThe morphological characteristics of the electrospun nanofibers were observed using a scanning electron microscope (Hitachi, S-4800). The diameter of nanofibers was determined using an image processing software (ImageJ). The average diameter was then calculated randomly from about 100 different nanofibers using MS excel software [19]. Chemical analysisChemical characterization of the nanofibers was observed using Fourier transform infrared (FT-IR) spectrometer (GXPerkinElmer- USA) [19]. Mechanical analysisThe tensile strength of the nanofibers was measured using a material testing machine Zwick Z2.5 (Germany). Each sample was cut to dimensions 15 mm in width and 50 mm in length. The test speed was 10 mm/min and the gauge length was 30 mm. Measurements were repeated 3 times. The result was presented as mean %u00b1 SD (standard deviation) [20].Wetting studyWetting property of the nanofibers was conducted by sessile drop method using an optical contact angle equipment