Development of biofilm microenvironment in microfluidic system for investigating antimicrobial materials

Abstract

Biofilm is a very important issue because it can cause secondary infections in medical devices and decreasing the efficiency of various devices in the industrial field. For this reason, many researchers have made a lot of efforts to control biofilm. As a results, various antibiotics and antimicrobials have been produced. However, in the case of antibiotics, it is not good in terms of efficiency because it must be used continuously, and other antimicrobial substances do not have a great effect. That is why new antimicrobial substances are needed. Recently, graphene, a carbon nanomaterial, has been actively studied as a new antimicrobial substance. However, there are contradictions that graphene actually affects bacterial growth with certain mechanisms. In addition, since experiments with bacteria in dishes or wells are far from actual ones, there is a limit to obtaining results that are different from actual ones. In this thesis, we tried to solve the above problems. First, we tried to determine antimicrobial effect of graphene by oxidative stress which is known to be a major factor. As a result, it was confirmed that the higher the oxidative stress, the stronger the antimicrobial activity. Second, the microfluidic device was used to more precisely simulate the growth environment of the bacteria. The microfluidic device can precisely control the mechanical and chemical factors to create a dynamic environment. It is possible to simulate a dynamic environment in which there is flow, not a static environment such as dishes or wells. Finally, we tried to quantify the biofilm control in the actual flow environment of graphene by combining the graphene and the microfluidic device. As a result, it was observed that graphene had excellent antimicrobial activity even in the dynamic environment.