Ultrafast protein preconcentration by nanoscale molecular traps
K.T. Liao, T. Leichle, C.F. Chou
Academia Sinica, TW
Keywords: biosensor, dielectrophoresis, protein, trapping
Abstract:Various techniques have been developed in recent years to achieve protein preconcentrations. Among these approaches, 10^3-10^6-fold preconcentration of proteins has been demonstrated using ion exclusion-enrichment effect caused by electrical double layer overlapping at a micro-to-nanofluidic interface. However, this approach for protein preconcentration and collection takes 30 minutes to several hours. An alternative way to construct protein traps by patterning geometrical constrictions in an insulating substrate using insulator-based dielectrophoresis (DEP). Since proteins are not easily polarizable due its mostly spherical shape and small sizes, we realized our insulator-based DEP protein trapping structures with nanoscale constrictions defined in nanofluidic channels. Here we report effective and ultrafast protein trapping using these devices. The highlight of our findings is that protein concentration may be enhanced by 10^3-10^6-fold in just seconds, 2~3 orders of magnitude faster than previous studies. Our approach may find practical applications in a micro-total analysis system for early disease diagnostics or protein assays in general.