Micro-reagent Dispensing Method Based on Pulse Driving & Controlling of Micro-fluids Technology and Application Research

With the development of bioanalytical technique and high throughput screening techniques, the amount of reagent was decreased to nanoliter and even picoliter level. To achieve high precision of micro-reagent dispensing, a two-channel micro-reagent dispensing system based on pulse driving & controlling technique of micro-fluids was developed. Then, taking glycerine solution as dispensing reagent, influences of viscosities, inner diameter of the micro-nozzle, driving frequency, and voltage amplitude on the dispensing volume were investigated. With the voltage amplitude of 70 V, driving frequency of 4 Hz, and 100 μm inner diameter of the micro-nozzle, different ratios of Na2HPO4 to KH2PO4 solution were prepared to study the mixing-reaction. In the experiment, a 3 × 3 phosphate buffer arrays solution with a pH gradient was first prepared. pH indicator was then added to detect the acidity and alkalinity of the mixed solution. The results showed that the relative standard deviation (n = 9) of spots diameter of the prepared pH gradient arrays was 0.8%; the spots were fully reacted, and uniform colors and significantly changed gradients were achieved. By the micro-reagent dispensing method based on pulse driving & controlling of micro-fluids technique, parallel, automated and micro volume (picoliter) dispensing with higher dispensing precision and higher repeated accuracy could be realized, and especially, micro reaction with different ratios could be achieved without separate “reaction pools”.

Two kinds of reagents with different properties could be dispensed with the system simultaneously which was automated and with micro volume (picoliter) resolution, and injected and deposited onto the substrate, solutions with gradient concentrations or ratios could be prepared without “reaction pools” by adjusting the two channel driving parameters.Figure optionsDownload as PowerPoint slide