Abstract
.Significance: Performance improvements in microfluidic systems depend on accurate measurement and fluid control on the micro- and nanoscales. New applications are continuously leading to lower volumetric flow rates.Aim: We focus on improving an optofluidic system for measuring and calibrating microflows to the sub-nanoliter per minute range.Approach: Measurements rely on an optofluidic system that delivers excitation light and records fluorescence in a precise interrogation region of a microfluidic channel. Exploiting a scaling relationship between the flow rate and fluorescence emission after photobleaching, the system enables real-time determination of flow rates.Results: Here, we demonstrate improved calibration of a flow controller to 1% uncertainty. Further, the resolution of the optofluidic flow meter improved to less than with 5% uncertainty using a molecule with a 14-fold smaller diffusion coefficient than our previous report.Conclusions: We demonstrate new capabilities in sub-nanoliter per minute flow control and measurement that are generalizable to cutting-edge light-material interaction and molecular diffusion for chemical and biomedical industries.
Highlights
Many new miniaturized systems in drug delivery handle sample flows in the range of micro- to nanoliters per minute
We have previously reported on an optofluidic flow meter capable of traceable flow measurements down to 10 nL∕ min using a similarity solution and associated scaling
In a previous manuscript,[15] we described an optofluidic system capable of dynamic flow measurements to 10 nL∕ min with relative uncertainty that was scaled down from a calibrated thermal flow meter at a much higher flow rate
Summary
Many new miniaturized systems in drug delivery handle sample flows in the range of micro- to nanoliters per minute. Advanced analytical instrumentation, such as high-performance liquid chromatography methods, go even further, using effluent flow rates as low as 5 nL∕ min.[3,4] micro- and nanodispensing (e.g., microdroplets) are utilized increasingly to compartmentalize and process small amounts of liquid for a wide range of applications, including analysis of single bacteria and compartmentalization of biomolecular reactions.[5,6,7,8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
