< BK21 플러스 BEST 정보기술 사업단 세미나 개최 안내 >

개최일시 : 2015년 5월 4일 월요일 16:00 ~ 18:00  

개최장소 :  제 1공학관 A563

세미나 제목 : A Novel Fabrication Method for Non-Spherical Metal Nanoparticle Surface Plasmon Sensor

발표초록 : Proteomics requires an array type tool as a sensor for gene expression and protein expression analysis including post-translational modifications. While it is easy to fluorescently label cDNA, and GFP fusion proteins are a powerful tool to detect the expression of proteins, most identification procedures still involve the binding of an immunolabel for fluorescence. Secondary labeling, however, involves extensive washing and increased background due to non-specific interactions. Additionally, labels are impossible to develop for large screening of candidate libraries of drugs, where labeling steps could also interfere with binding. Also, fluorescence is often not easily quantifiable, which makes binding kinetics studies difficult. Label-free detection methods are therefore needed in many applications, and surface plasmon resonance in thin metal films has become a standard method for measuring binding kinetics. Nano metal particle surface plasmon resonance, in which the electronic resonance linearly changes with a change in the environment and mass at the surface, provides real time non-labeling analysis in proteomics. This method which is detected by simple absorption measurement in a UV-Vis spectrometer overcomes many drawbacks of current fluorescent labeling methods with cDNA and GFP. Non-spherical high-density nano-array suggests highly sensitivity, simple method and more parallel detection than label-free methods. However, irreproducible particle surface plasmon resonance in nanoparticles by nanosphere lithography has been a critical issue because sharp features are often not stable under changing chemical environments such as during bioconjugation procedures. We present a new method which is carbon based template-stripping method in ultraflat nanosphere lithography. We deposit nanospheres as a self-assembly shadow-mask on a hydrophilic carbon layer. At the final lift-off step, we simply remove the carbon layer by O2 plasma treatment. With our new technique, we found an increase in thickness of the metal particle causes the spectral peak to shift to the blue, but also leads to decreased sensitivity. However, as the length of the largest bisector on the tetrahedron particle is increased, the peak position shifts to the red, while increasing the sensitivity. Thus, highest sensitivity is achieved with particles that highly non-spherical this thin but elongated shapes. The resulting array of silver or gold nanoparticles is capable of detecting thiol surface modification and protein binding. Since each gold or silver particle can principally acts as an independent sensor, it can be miniaturized without loss of sensitivity. Since atomic scale flat surface is also precious for protein absorption study, carbon based template-stripping method for ultraflat surface with any type of nanostructures will provide a big step in protein adsorption study.

강연자 : 정봉수 박사 / 책임 연구원, DGMIF

초청자 : 전기전자공학과 교수 김태욱