Category: Automation and High-Throughput Technologies
For the most of molecular biological experiments, liquid handling and absorbance measurement are the most important and essential procedures and steps. In particular, the absorbance measurement is an essential technique to measure and determine concentrations of DNA, RNA and proteins in samples. Absorbance measurement is done by spectrophotometer instruments capable of easily measuring the absorbance of a solution of several μL to mL scale.
At the current laboratories, most of laboratories manually measure the concentrations of DNA, RNA and protein samples, such as protein concentration measurement of each fraction after gel filtration of protein samples or DNA concentration measurement after extraction and purification of plasmid DNA from E.coli. After measurement of DNA, RNA and protein concentrations, researcher or laboratory technician usually use certain amount of DNA or protein from original tube and/or make dilution for next steps of molecular biology experiments such as DNA-DNA ligation and enzymatic digestion of proteins and so on. Those steps are simple manual procedures, but also those are time consuming and there are risks of failed experiment caused by human error. In addition, for some molecular biology experiments, the accuracy of DNA, RNA and protein concentration are crucial to obtain reliable and stable results.
OGAB (Ordered Gene Assembly in Bacillus subtilis) method is a powerful method for genome editing for synthesizing more than 50 kbp artificial genome based on the nature of genome accumulation and transformation by Bacillus subtilis. In the synthesis of long-chain artificial genome DNA by the OGAB method, it is necessary to measure the absorbance of more than 48 different DNA samples and need to dispense certain amount of a minute amount. In this case, accuracy of DNA concentration measurement and DNA amounts used for ligation reaction are crucial for obtaining efficient amount of transformed Bacillus subtilis which has corrected order and sequence of artificial genomic DNA, therefore, we developed an automation system for part of processes of OGAB (Ordered Gene Assembly in Bacillus subtilis) method, such as automated DNA concentration measurements and precise dilution of DNA as defined concentration to get efficient synthesis of artificial genome by OGAB method.
In this poster, we will show the automate system for measuring and adjusting DNA concentration. Measurement principle of DNA concentration is as follows. Aspirate the solution to be measured with a black dispensing tip, irradiate light from top of the tip, and introduce the light transmitted through DNA solution in black tip to the spectrophotometer through an optical fiber mounted in the dispensing syringe to measure absorbance. In addition to automatic measurement and adjustment of DNA concentration results, we also will show examples of application to the OGAB method. We have succeeded to demonstrate efficient ration of synthesis of artificial genomic DNA by using developed technologies that enable fully automated micro dispensing and absorbance measurement. Those technologies are also able to use for other molecular biology applications such as DNA sequencing sample pretreatment and ELISA, and general purpose biochemical experiments.
Tetsuya Ueda– Director of LSM business division, Precision System Science Co.,Ltd., Mastud-shi, Chiba, Japan