High-performance Concentration And Detection Of Proteins On Chips Based On Dielectrophoresis And Metal-enhanced Fluorescence

Proteins play critical roles in regulating biologically relevant activities and therefore are important in biochemistry and physiology.However,the protein biomarkers are usually at low concentration in the early stage of diseases.Dielectrophoresis,as a common method for biomolecular manipulation,is widely used in the enrichment and separation of cells.Proteins' dielectrophoresis refers to movement of proteins in nonuniform electric field due to polarization.The movement direction of proteins is consistent with(or opposite to)the electric field gradient,so corresponding structures can be designed to do the protein manipulation and further enrichment.However,the existing protein enrichment structures based on dielectrophoresis are usually ineffective or need more expensive advanced microfabrication.In this paper,a novel protein enrichment and detection chip are proposed.The oxide coated silver nanorod arrays on the chip can enhance the dielectrophoresis effect and fluorescence enhancement effect,which work together to improve protein enrichment and detection sensitivity.The chip is composed of detection devices integrated with nanostructure and PDMS channel.Microelectrodes and oxide coated silver nanorod arrays are fabricated by lithography,sputtering and evaporation,and PDMS channel is fabricated by soft lithography.The experimental results showed that the enrichment efficiency for protein based on dielectrophoresis was improved by around 100-fold,and the detection sensitivity of fluorescent protein based on fluorescence enhancement was improved by around 50-fold.Apply the two effects on antigen's detection,and the detection limit reaches 21.25 pg/m L.The chip can also detect a variety of biomolecules simultaneously with good specificity.What's more,the chip can be fabricated at low cost without complicated microfabrication.In conclusion,the proposed protein enrichment and detection chip integrated with oxide coated silver nanorods can greatly improve the protein enrichment efficiency and detection sensitivity.