Breast-Cancer-Stem-Cell Sensor Using Igzo Nomfet Implemented with Au Nano-Particles

Abstract

Recently, many researchers have studied circulating-cancer-stem-cell (CCSC) to pre-recognize the presence of a cancer. Since, it has been that cancer cells include negative or positive charges, several electronic sensors have been attractively proposed. In our study, we designed an In-Ga-Zn-oxide (IGZO) based FET implemented with Au nano-particles on IGZO channel, as shown in Fig. 1(a). The average size and density of the Au nano-particles on the channel were 12.05 nm and 2.66×1011 cm-2, respectively. In particular, this FET has a unique time-dependent current characteristic such as depressing at a positive gate bias or facilitating at a negative bias, which determines whether or not the cancers present a fixed charge or mobile charges. In our experiment, breast-cancer-stem-cell (BCSC) connected with the cancer-anti-body (CD44) was dropped on the IGZO FET with Au nano-particles where a linker (8-Mercaptooctanoic acid) was attached on Au nano-particles, as shown in Fig. 1(b). The linkers were well uniformly absorbed and attached on Au nano-particles, confirmed by FT-IR, as shown in Fig. 2. First of all, we investigated the dependency of threshold voltage on the presence of Au nano-particles, linkers, and breast-cancer-stem-cells with anti-bodies shown in Fig.3. The threshold voltage of the IGZO FET without Au nano-particles was +2.4 V. The implementation of Au-nano-particles on the IGZO channel increased from +2.4 to +12.0 V because of the presence of positive fixed charges at the interface between the IGZO channel and Au nano-particles. The attachment of the linker on Au nano-particles decreased the threshold voltage from +12.0 V to +6.9 V since the functional group of the linker was carboxyl. Two kinds of breast-cancer-stem-cells were dropped on the linker connected with Au-nano-particles; i.e., the cells without or with anti-body. The cells without anti-body did not shift threshold while the cells with anti-body reduced -4.3 V where the concentration of BCSC was 8000ea/10ul. The threshold-voltage shift amount was well correlated with the concentration of BCSC, as shown in Fig. 4. The threshold-voltage shift amount increased linearly with the concentration of BCSC, having the slope of the threshold-voltage shift amount of 0.44V/(kea/ul). In addition, we confirmed that BCSC showed a negative fixed charge rather than mobile charge by testing time dependent drain-current characteristic. In our presentation, we will review the detailed mechanism by which BCSCs shift threshold voltage and show a negative fixed charge characteristic. Reference [1] F. Alibart et al. Adv. Funct. Mater. 20 330. (2010)[2] K.-C. Kwon et al. Appl. Phys. Exp. 6, 067001 (2013).[3] XiuHua Zhang et al. Sensors, 3, 61-68 (2003) Acknowledgment This research was supported by the Converging Research Center Program funded by the Ministry of Science, ICT & Future Planning (Project No. 2015054348) and supported by Brain Korea 21 PLUS Program in 2014 Figure 1