The Antibacterial Activity About Inorganic Compounds Of Gallium

In recent years, due to the overuse of antibiotics, a large number of resistant bacteria have come into being, to produce new antimicrobial agents is extremely urgent. Antibacterial materials have drawn much attention because they can eliminate bacterial cross-infection between people and people, people and objects, objects and objects and can prevent from bacterial drug-resistant. The inorganic antibacterial materials with advantages such as high heat resistance, using convenience, good chemical stability, wide antibacterial spectrum, long-effectiveness, little drug-resistance and high safety to human bodies and so on, draw much attention of the developers. Various types of inorganic antibacterial material with excellent antibacterial properties have been brought to us. These inorganic antibacterial material are widely used in fiber, ceramics, plastics, building materials, paints, enamels and many other fields. Currently the inorganic materials widely researched are mainly focused on Ag, Cu, Zn, Ti and other element of rare metals as well as their oxides. Though gallium compound has been recognized by FDA to treat hypercalcemia caused by therioma, there are a few of literatures related to the research of antimicrobial activity of the gallium nitrate and none of gallium oxides.In this article, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa isolated from clinic were used as the research object to study the antimicrobial properties of gallium nitrate and the impact on the biofilm of Pseudomonas aeruginosa. Nano gallium oxide was prepared by hydrothermal method, we studied the antibacterial properties of nano Gallium oxide by detecting the antibacterial rate for Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. To explore the antimicrobial mechanism of gallium nitrate, iron and gallium nitrate were added into medium without iron to detect cell concentration and iron concentration of Pseudomonas aeruginosa by atomic absorption spectrophotometer, and gallium ions were added into CAS siderophore detection plate to detect siderophore content and gallium ions were added into medium to analysis protein expression of Pseudomonas aeruginosa.The results of the experiment are as follows:94.55% of Escherichia coli can be killed by 10μM Ga(NO3)3 within 1.5h.94.31% of Staphylococcus aureus can be killed by 20μM Ga(NO3)3 within 1.5h and 95.17% of Pseudomonas aeruginosa can be killed by 20μM Ga(NO3)3 within 2h.Gallium nitrate at low concentrations has good inhibitory effect on the biofilm formation of Pseudomonas aeruginosa.98.53% of Escherichia coli can be killed by 20mg/L Gallium oxide solution within 1.5h, which is the same with 95% of Staphylococcus aureus and 93.35% of Pseudomonas aeruginosa. Gallium ions affected the absorption of iron into bacteria, the antimicrobial mechanism of gallium ions may be that Gallium and Iron ions got into the cells competitively, which blocked the metabolism of Iron and influenced the growth of bacterial.The results of the experiment showed that Gallium nitrate and Gallium oxide had good antibacterial activity for common bacteria. Gallium ions probably interdict the metabolism of Iron and kill the bacteria by competing with Iron for entering the cells. The excellent antibacterial activity of inorganic gallium compounds was proved by the experiment. Moreover, gallium ions have been admitted by FDA that it is more security and can be applied to the clinical treatment. Nano-gallium oxide which is the powder also can be added to the inorganic materials to process as antibacterial materials, which has the broad application prospect.