성형 금나노입자 응집을 이용한 Ara h1 검출법 연구

Abstract

There has been a lot of research aimed to develop an easy, rapid and sensitive detection method for useful/harmful biomaterials and microorganism in food system. However, current techniques have their own problems such as complicate sample preparation of time-consuming steps, low sensitivity, and necessity of trained experts or sophisticated instruments. In the preceding studies, a rapid and simple detection method using gold nanoparticle (AuNPs) was developed. This method is carried out in two steps. In the first, the target is mixed with switchable linker (SLs) with various concentrations. After the first step, streptavidin coated AuNPs (stAuNPs) are added to the above solutions. Because of high affinity of biotin to streptavidin, biotins on the SLs connect with the streptavidin on the stAuNPs and form huge aggregates. Without the target, region of forming aggregates is naturally appeared by the relationship between the concentrations of the SLs and stAuNPs. However, when the targets are added, the SLs covered with targets have less ability to connect with stAuNPs than naked SLs. This resulted in a change of the quantitative relationship mentioned above, which led to shift of the aggregation region. Therefore, in this quantitative relationship, the number of streptavidin on stAuNPs is one of the key factors. In this study, streptavidin on stAuNPs was modified to improve this detection system. Firstly, the effect of the number of streptavidin on stAuNPs on the range exhibiting a visible color change (REVC) and reaction time was investigated. The less number of streptavidin on stAuNPs allowed REVC forming region to shift to lower concentrations of SLs and it took more time for making enough aggregation. However, by agitating during they are forming REVC, time for forming REVC was reduced. Finally, after optimized streptavidin modifying level on stAuNPs. Obtained particles are used to detect Ara h1, major peanut allergen. This detection system using modified stAuNPs could detect very low concentration of Ara h1 (10 nM), without sophisticated equipment. It was also tested with peanut extract and could be distinguished by naked eye in solution to 100-fold diluted extract. Thus, the result of this study could be used as valuable references for improving and applying this detection system to real food system.