title: Universal handheld micropipette.
abstract: The handheld micropipette is the most ubiquitous instrument for precision handling of microliter-milliliter liquid volumes, which is an essential capability in biology and chemistry laboratories. The range of one pipette is typically adjustable up to 10-fold its minimum volume, requiring the use and maintenance of multiple pipettes for liquid handling across larger ranges. Here we propose a design for a single handheld pipette adjustable from 0.1 μl to 1000 μl (i.e., 104-fold) which spans the range of an entire suite of current commercial pipettes. This is accomplished by placing an elastic diaphragm between the existing pipette body and tip, thereby de-amplifying its native volume range while maintaining its simple manual operating procedure. For proof-of-concept, we adapted a commercial pipette (100-1000 μl nominal range) with a selection of rubber sheets to function as the diaphragms and confirmed the accuracy and precision of drawn volumes are within international ISO-8655 standards across the entire 104-fold volume range. The presence of the diaphragms introduces a nonlinear mechanical behavior and a time-dependency due to heat transfer, however, by model and experiment, these are redressed so as to maintain the pipette's accuracy and precision.
authors.affiliation: Mechanosynthesis Group, Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, 35-010, Cambridge, Massachusetts 02139, USA.
authors.forename: Justin
authors.initials: J
authors.lastname: Beroz
authors.affiliation: Mechanosynthesis Group, Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, 35-212, Cambridge, Massachusetts 02139, USA.
authors.forename: A John
authors.initials: AJ
authors.lastname: Hart