The National Institute of Standards and Technology (NIST) has filed a provisional patent application for a microflow measurement system, about the size of a nickel, that can track the movement of extremely tiny amounts of liquids—as small as nanoliters (nL, billionth of a liter) per minute. If water were flowing at that rate from a 1-liter bottle of water, it would take about 200 years to drain.
The invention is designed to fill an urgent need in the rapidly expanding field of microfluidics, in which precisely measuring tiny flow rates is critical. For example, some medical drug-delivery pumps dispense as little as tens of nL per minute into the bloodstream. For comparison, a single drop of water contains 50,000 nL. Clinical diagnostics, chemical research, cell sorting and counting, and continuous-flow micromanufacturing—essentially tiny factories that work nonstop to make small quantities of liquids—also increasingly require accurate measurements of similarly minuscule volumes.