Kimimichi Obata

Development of a novel method for operating magnetic particles, Magtration Technology, and its use for automating nucleic acid purification

Magnetic particles are useful for simple and efficient nucleic acid extraction. To achieve fully automated nucleic acid extraction and purification using magnetic particles, a new method for operating magnetic particles, Magtration Technology, was developed. In this method, magnetic separation is performed in a specially designed disposable tip. This enables high recovery of magnetic particles with high reproducibility. The features of this technology are (i) a simple mechanism for process control and (ii) flexible software to enable adaptation to commercially available reagents. Automated instruments based on Magtration Technology were developed and used for nucleic acid extraction. Total DNA, total RNA and plasmids were purified by Magtration Technology at an efficiency comparable to that of manual methods.

Fully automated immunoassay system of endocrine disrupting chemicals using monoclonal antibodies chemically conjugated to bacterial magnetic particles

The development of a rapid and high-throughput detection system for endocrine disrupting chemicals (EDCs) has been required in the recent years. A fully automated immunoassay system was described for the detection of EDCs, such as alkylphenol ethoxylates (APEs), bisphenol A (BPA) and linear alkylbenzene sulfonates (LASs), using monoclonal antibodies chemically conjugated to bacterial magnetic particles (BMPs) and alkaline phosphatase (ALP)-conjugated EDCs. EDC concentrations were evaluated by the decrease in luminescence based on the competitive reaction of EDCs and ALP-conjugated EDCs. Full automation of the BMP-based immunoassay was achieved by using an automated eight-way pipet moving at X-, Y- and Z-direction and a B/F separation unit. B/F separation was performed on the tip surface of eight-way pipet with a retractable magnet mounted close to the pipet tip. Immunoreactions were saturated after 10 min, and the assay was completed within 15 min. The detection ranges for APE, BPA and LAS were 6.6 ppb–66 ppm, 2.3 ppt–2.3 ppm, and 35 ppt–35 ppm, respectively. This BMP-based immunoassay system has advantages due to its high sensitivity and rapid measurement of samples.

Recent developments in laboratory automation using magnetic particles for genome analysis

The majority of research for genome analysis has shifted from nucleic acid sequencing to the biological functional analysis of each gene. Based on past success, it may not be long before genome diagnostics becomes a widespread tool in human, veterinary and botany research fields. Genome analysis involves the processes of nucleic acid purification, amplification, labeling and signal detection (specific reaction, separation and signal counting). Except for the purification of nucleic acids, the other processes cannot be achieved without instruments, resulting in the advancement of automation processes. Since purification of nucleic acids can be done manually, automating this process has been delayed. However, because the purification of nucleic acids using magnetic particles is suitable for automation, its development has also been accelerated. The need for full automation for other processes is not as great because the majority of genome analysis is to identify the nucleic acid sequence and analyze genome expression. However, once useful diagnostic tools are generated, the desire for full automation will significantly increase. In order to develop realistic and practical automation, various technologies developed for each process in genome analysis have to be evaluated and only a few technologies, useful for automation, selected. The other key factor in automation is the development of methods to manage reagents and reaction mixtures precisely without any risks specifically related to genome handling, such as cross-contamination. Methods using magnetic particles, which have been used for the automation of nucleic acid purification and immunoassay, appear to be the most promising way to automate processes used in biological research.