The proprietary method for electrophoretic mobility assessment used by Ranger Technology enables it to control that mobility through real-time voltage manipulation. This control is exercised continuously until the target DNA fraction has arrived at a point in the gel cassette from which it can be extracted. When that is achieved, Ranger Technology initiates the extraction process, ensuring the precise target DNA fragment lengths are recovered over multiple samples.
Fragment Analyzer (Advanced Analytical Technologies) evaluation of small RNA libraries that have gone through size selection with Ranger Technology. A target range of 130bp to 150bp was set for each sample, and each sample was processed repeatably despite differences between the samples that led to varied electrophoretic mobilities. (Image courtesy of Dr. J. Russ Carmical, Center for Metagenomics & Microbiome Research, Baylor College of Medicine).
Accurate Fragment Length Estimation
Throughout the electrophoretic documentation process, Ranger Technology captures images to record the mobility of DNA in the sample. During each imaging sequence photos are taken with a blue excitation lights, and then another with red excitation lights. The blue images reveal the location of all DNA in the sample. The red images reveal only the location of internal reference markers, which are exclusively labelled with a secondary fluorophore.
This two-colour system allows Ranger Technology to leverage reference markers that are close in size to the desired DNA size range of interest. The internal reference markers are always identified by Ranger Technology’s machine vision suite, regardless of overlap with DNA fragments of similar length. Coastal Genomics supports a variety of different internal reference marker sizes that users can select from to optimize the performance of the platform for specific assays.
Assessment of GeneRuler 100 bp Plus dsDNA ladder (Thermo Fisher). Electrophoretic traces, as well as human- and machine-readable reports, are generated by Ranger Technology.
High Recovery Yields
Ranger Technology combines accurate fragment length estimation and controlled migration of DNA to ensure that the recovery operation is conducted over the entire span of the target fragment lengths. Our internal testing reveals that recovery yields are consistently over 70%. Extraction volumes can be kept to under 35 ul volumes to ensure high concentration of DNA for downstream processing.
Ranger Technology recovered all fragments between 70bp and 190 bp from a 20 bp dsDNA ladder (Lonza). Comparison of the electrophoretic traces of the input and size selected fraction indicate an average recovery yield of 73% across all targeted fragment sizes. Further tests involving solution-based fluorometric assays confirm recovery yields to be in excess of 70% (data not shown).