Throughout the scientific literature, sample preparation protocols specify the need for “wide bore” pipette tips and cannulas to minimize the inadvertent harm, which can be applied to native biological sample matrices during sample preparation. Loss of biological sample integrity can occur when pipetting fragile cell suspensions, hybridomas, embryoid bodies, algal coagulates, protein aggregates, and genomic materials due to the pipette tips’ small internal orifice diameter and the speed of aspiration and dispense during pipetting. This has led researchers to report, “cutting 2 to 3 mm from the end of the tips” to increase the internal diameter, or bore, of standard pipette tips. This practice achieves the intended result albeit in an imprecise manner and with a shortening of the tip, which reduces the pipette tip volume and limits labware access.
Biomek Automated Workstations, and their associated software, provide greater control and reproducibility over pipetting techniques to minimize the disruption of sample integrity vs. manual pipetting, but the internal diameter of the pipette tip orifice may demand a slowing of pipetting speeds to compensate for the turbulence [and shear] caused within the narrow diameter pipette tip. Biomek Wide Bore Pipette Tips have been designed to address such sample preparation challenges. Through the use of Computational Fluid Dynamics (CFD) software, physical forces and flow characteristics within a pipette tip during pipetting have been simulated. In this virtual CFD world, comparisons of pipette tip orifice diameters can be analyzed for such parameters as fluid (sample) velocity, wall shear, and shear strain rate. Less wall shear effects and shear strain rates are desirable in preserving the biological integrity of native samples during sample preparation. Wall shear occurs within a pipette tip at the plane of contact between the sample fluid and the inside wall of the pipette tip. Shear strain rate indicates the rate of change in displacement of the faces of a sheared layer of sample fluid.