ABSTRACT
A single-step concentration and elution method is developed for detection of DNA in buffer, saliva, and blood. A nanotip capturing DNA using an electric field and capillary action is directly dissolved in buffer for qPCR analysis. The concentration yield and the relative parameters are compared with those of a commercial kit.
Subject(s)
Analytic Sample Preparation Methods/methods , DNA/genetics , DNA/isolation & purification , Nanotechnology/methods , Polymerase Chain Reaction/methods , Bacteriophage lambda/genetics , Carbon Compounds, Inorganic/chemistry , DNA/analysis , DNA/blood , DNA, Viral/analysis , DNA, Viral/genetics , Genome, Human/genetics , Humans , Nanowires/chemistry , Saliva/chemistry , Silicon Compounds/chemistry , Time FactorsABSTRACT
Various nanowire or nanotube-based devices have been demonstrated to fulfill the anticipated future demands on sensors. To fabricate such devices, electric field-based methods have demonstrated a great potential to integrate one-dimensional nanostructures into various forms. This review paper discusses theoretical and experimental aspects of the working principles, the assembled structures, and the unique functions associated with electric field-based assembly. The challenges and opportunities of the assembly methods are addressed in conjunction with future directions toward high performance sensors.
ABSTRACT
Rapid, low cost screening of tuberculosis requires an effective enrichment method of Mycobacterium tuberculosis (MTB) cells. Currently, microfiltration and centrifugation steps are frequently used for sample preparation, which are cumbersome and time-consuming. In this study, the size-selective capturing mechanism of a microtip-sensor is presented to directly enrich MTB cells from a sample mixture. When a microtip is withdrawn from a spherical suspension in the radial direction, the cells that are concentrated by AC electroosmosis are selectively enriched to the tip due to capillary- and viscous forces. The size-selectivity is characterized by using polystyrene microspheres, which is then applied to size-selective capture of MTB from a sample mixture. Our approach yields a detection limit of 800 cells mL(-1), one of the highest-sensitivity immunosensors to date.
