Production of alginate microspheres of various sizes under the influence of an electrostatic field with the help of electrospray method

Abstract

Background: Microspheres obtained from polymers, both natural and synthetic origin, have found application in chemical-pharmaceutical, food industries and in agriculture. Despite this, various methods of obtaining them are actively developing. The main requirements for the preparation of microspheres are low cost, homogeneity of the end product, mild conditions of their obtaining. One of the promising methods to produce the microspheres, which meets the stated requirements, is the electrospray method. At the present time, a large number of studies have been carried out to study the effect of an inhomogeneous electric field on the dimensions of microspheres from polymeric materials, while at the same time there are practically no published reports devoted to the investigation of the influence of a homogeneous electric field on their dimensions. Objectives: The purpose of this study was the investigation of the influence of the electrostatic field uniformity on the size of the sodium alginate microspheres obtained by means of electrospray. Materials and methods: The sodium alginate microspheres were prepared by the electrospray method, on the condition of homogeneity of electrostatic field formed between the contacts of the device. Sodium alginate of low viscosity (15·10-3–25·10-3 Pa·s) was used in the work. As a gel solution, a 2% solution of CaCl2 was used. The sizes of the microspheres were evaluated with a confocal microscope AxioObzerver Z1 (Carl Zeiss, Germany). Results: During the study, there were revealed the main parameters of the experimental setup, which affected the sizes of the obtained microspheres. These include the magnitude of the voltage applied to the plates determining the shape of the field, the distance between the plates, and the rate of the polymer supplying. The most important parameters comprise the magnitude of the applied voltage since it was the change in this value that led to the largest change in the sizes of the alginate microspheres. Conclusions: Upon using the uniform electrostatic field it is possible to obtain the sodium alginate microspheres with a diameter from 900±5 μm to 2071±15 μm, on the condition of maintaining the spherical shape of the particles.