Effects of electric charges on serum protein aggregation induced by a low temperature atmospheric pressure plasma

Abstract

To understand the aggregation mechanism of serum protein dispersed in the solution of distilled water induced by a low temperature atmospheric pressure plasma, we compared the relationship between the amount of aggregation and experimental condition dependencies such as gas species, gas flow rate, and the distance between the plasma device and the solution. In this experiment, pure argon, helium, and/or a mixture of helium and argon gases were used. From statistical analyses of various experimental conditions, it was found that a monotonic supply of total absolute charge in one period was important for protein aggregation. When the coefficient of variation (standard deviations/averaged total absolute charges during one period) is small, the amount of protein aggregation becomes larger. Excess or scarcity of averaged total absolute charges does not appear to relate to protein aggregation phenomena; however, the coefficient of variation strongly relates to the mechanism of protein aggregation. Therefore, a possible serum protein aggregation process by low-temperature plasma treatment was proposed in which the serum protein, which had negative charges in the solution, was locally aggregated through the trigger of charge neutralization induced by a stable charge supply, and/or positively charged aggregated protein on the solution surface attracted serum protein in the solution to the surface.