Acoustic Droplet Ejection Technology and Its Application in High-Throughput RNA Interference Screening

Abstract

The development of acoustic droplet ejection (ADE) technology has resulted in many positive changes associated with the operations in a high-throughput screening (HTS) laboratory. Originally, this liquid transfer technology was used to simply transfer DMSO solutions of primarily compounds. With the introduction of Labcyte’s Echo 555, which has aqueous dispense capability, the application of this technology has been expanded beyond its original use. This includes the transfer of many biological reagents solubilized in aqueous buffers, including siRNAs. The Echo 555 is ideal for siRNA dispensing because it is accurate at low volumes and a step-down dilution is not necessary. The potential for liquid carryover and cross-contamination is eliminated, as no tips are needed. Herein, we describe the siRNA screening platform at Southern Research’s HTS Center using the ADE technology. With this technology, an siRNA library can be dispensed weeks or even months in advance of the assay itself. The protocol has been optimized to achieve assay parameters comparable to small-molecule screening parameters, and exceeding the norm reported for genomewide siRNA screens.

Unlocking the efficiency of genomics laboratories with robotic liquid-handling

“…Alternatives to tip-based dispensing also exist. Acoustic droplet ejection (ADE) technology involves completely contactless liquid handling using sound energy [32]. To eject a small volume droplet from a well, acoustic energy is focused near the surface of the liquid where the frequency of the acoustic wave determines the volume of the droplet.…”

“…In the case of acoustic droplet ejection systems, such as the Echo 650 series, liquid dispensing is contact-less which largely eliminates any source of contamination [32]. There is also the distinction between open and enclosed systems, given that open systems, those not enclosed within four walls, would definitely be more susceptible to contaminations from the environment.…”

Why a Special Issue on Acoustic Liquid Handling?

“…Cain-Hom et al 28 show that they can reduce genotyping assay volumes by 75% while improving results. Agrawal et al 29 use ADE to miniaturize quantitative reverse transcriptase (qRT)-PCR assays, while Nebane et al 30 show how ADE allows miniaturization of a high-throughput RNA interference assay. Other researchers have used the microvolume transfers to run experiments in 1536-well [31][32][33][34][35][36][37] and 3456-well 38 formats.…”

Robotic Catalysis: A High‐Throughput Method for Miniature Screening of Mesoporous Metal Oxides**

“…The acoustic liquid handler dispenses nanodroplet (as small as 2.5 nL droplets) of a solution into a 96-well plate. This acoustic liquid handler is mostly used in biological applications such as drug discovery, [37] RNA interference studies, [38] for cell culturing and anti-cancer studies, [39][40][41][42] and many other biological applications. [43][44][45][46] Recently, an acoustic liquid handler was used for the preparation of boronic acid libraries.…”