Fluid Volume Assignment for Flow-Based Biochips: State-of-the-Art and Research Challenges

TL;DR

This paper reviews the state-of-the-art in fluid volume assignment for flow-based biochips, introduces algorithms for optimizing fluid usage, and discusses challenges and solutions to minimize fluid waste in biochemical applications.

Contribution

It provides a comprehensive review of volume management in flow-based biochips and proposes algorithms for optimizing fluid volume assignment and reuse to reduce waste.

Findings

Algorithms can significantly reduce fluid consumption.

Mixing technology impacts fluid volume requirements.

Reusing leftover fluids minimizes waste.

Abstract

Microfluidic biochips are replacing the conventional biochemical analysers integrating the necessary functions on-chip. We are interested in Flow-Based Microfluidic Biochips (FBMB), where a continuous flow of liquid is manipulated using integrated microvalves. Using microvalves and channels, more complex Fluidic Units (FUs) such as switches, micropumps, mixers and separators can be constructed. When running a biochemical application on a FBMB, fluid volumes are dispensed from input reservoirs and used by the FUs. Given a biochemical application and a biochip, one of the key problems which we are discussing in this paper, is in determining the fluid volume assignment for each operation of the application, such that the FUs' volume requirements are satisfied, while over- and underflow are avoided and the total volume of fluid used is minimized. We illustrate the main problems using examples, and provide a review of related work on volume management. We present algorithms for optimizing fluid volume assignments and for reusing leftover fluids to reduce waste. This also includes the optimization of mixing operations which significantly impact the required fluid volumes. We identify the main challenges related to volume management and discuss possible solutions. Finally we compare the outcome of volume management using fixed- and arbitrary-ratio mixing technology, demonstrating significant reductions in fluid consumption for real biochemical assays.