An improved method for magnetic bead separation: the BeadTenderTM

Isolation and purification of biomolecules (doubleand singlestranded DNA, total RNAs, mRNAs, miRNA, proteins), as well as specific cells and organs, facilitate a wide array of downstream applications in gene and protein expression studies, cloning, transfection, protein-protein interactions, immunology, clinical diagnostics, cDNA library synthesis, PCR and qPCR, Sanger and NGS sequencing, and more. Due to its simplicity, recovery efficiency and purity, magnetic separation has found its place in this bio-separation arena and gradually replaced the traditional liquid phase and solid phase separation methods, which require extensive centrifugation or vacuum filtration procedures that are difficult to automate. However, when reproducibility plays a vital role in obtaining the results, manual performance varies greatly between different operators and even for the same operator. Automation can standardize different procedures, significantly reducing this variability, but may be limited in other aspects such as liquid evacuation or efficient bead collection. The BeadTender method (Figure 1), is an automatic solution to manual magnetic bead manipulation exploiting the Andrew robot. It consists of a specific manipulation and magnetic design enabling beads separation, washing, and elution fully inside a conventional pipette tip. The proprietary method (patents pending) improves the reproducibility of the purified biomolecules, with the highest efficiency and flexibility in sample and elution volumes. The entire process of the BeadTender method is executed within a conventional tip connected to a conventional pipette. It encompasses sample aspiration, active bead mixing, bead washing, bead pelleting, incubation, drying, and finally sample elution. Thus, users are totally spared from manual operations and the repetitive stress injury caused by the manual bead resuspension at various steps. Completely independent of the consumables holding the samples, the BeadTender method is scalable for all common volume ranges of biological applications, with adjustable and optimizable parameters for bead manipulation adaptable to each and every protocol or bead type. Therefore, the BeadTender provides a flexible and universal solution to the small-scale automation of magnetic bead manipulation. Magnetic separation of biomolecules from a mixed sample is a complex manipulation significantly affected by variability. The BeadTender method automates magnetic separation of beads inside conventional pipette tips and produces biomolecules of high purity with a reproducibility up to eight times better than that of the most experienced human operators.