Fibroin is a biomaterial and in the powder form, has found application such as food and cosmetics additive as well as drug delivery. Various methods have been employed to produce fibroin powder with different degrees of fineness. This paper reports a novel and original technique, capable of producing fibroin powder in the sub-micron range. Our technique is based on electrospraying of dilute fibroin solutions. Moreover, the effect of material and process variables such as concentration of fibroin solutions, voltage, feed rate, needle –collector distance and surfactant has been studied. The result of this study showed that electrospraying is capable of producing nano powders with average particle size less than 100 nm. It is worth mentioning that fibroin particles obtained with this method alongside with the precipitation method are the lowest when compared with other methods reported in the literature. However, nano powder obtained through electrospraying technique enjoys a more spherical form as well as having a considerably lower degree of aggregation. As far as the process variables, chosen in this research, are concerned, it was shown that lower concentrations, lower feed rates and longer needle to collector distance led to a decrease in the average particle size of fibroin nano powder. Voltage decreased the particle size up to 20kV and with higher voltages, the average size increased. With high concentrations the particles showed an irregular form and were somehow connected to each other
