Two-dimensional micro-bubble actuator array to enhance the efficiency of molecular beacon based DNA micro-biosensors

Two-dimensional micro-bubble actuator arrays were developed and studied in detail to enhance the hybridization kinetics of a DNA micro-biosensor. The hybridization between a molecular beacon, a kind of oligonucleotide probe, and its complement was investigated in a millimeter-sized PDMS based reaction chamber, where various 2D micro-heater arrays were distributed on the bottom for micro-bubble generation. The hybridization assay without the micro-bubble actuation revealed that the fluorescence increased fast at the beginning and slowed down after that. However, a uniform fluorescence increase was observed when periodic micro-bubble agitation was introduced in the static hybridization solution. A comparison of hybridization assays with and without micro-bubble agitation revealed that the hybridization time could be effectively shortened by 33% with 10 cycles of micro-bubble agitation from a 2 × 1 bubble actuator array, and by 43% with 10 cycles of micro-bubble agitation from a 2 × 2 bubble actuator array.