Assessment of Flow through Microchannels for Inertia-Based Sorting: Steps toward Microfluidic Medical Devices.

Rucha Natu,Luke Herbertson,Seyed Ahmad Reza Dibaji,Suvajyoti Guha

doi:10.3390/mi11100886

Abstract

The development of new standardized test methods would allow for the consistent evaluation of microfluidic medical devices and enable high-quality products to reach the market faster. A comprehensive flow characterization study was conducted to identify regulatory knowledge gaps using a generic inertia-based spiral channel model for particle sorting and facilitate standards development in the microfluidics community. Testing was performed using 2–20 µm rigid particles to represent blood elements and flow rates of 200–5000 µL/min to assess the effects of flow-related factors on overall system performance. Two channel designs were studied to determine the variability associated with using the same microchannel multiple times (coefficient of variation (CV) of 27% for Design 1 and 18% for Design 2, respectively). The impact of commonly occurring failure modes on device performance was also investigated by simulating progressive and complete channel outlet blockages. The pressure increased by 10–250% of the normal channel pressure depending on the extent of the blockage. Lastly, two common data analysis approaches were compared—imaging and particle counting. Both approaches were similar in terms of their sensitivity and consistency. Continued research is needed to develop standardized test methods for microfluidic systems, which will improve medical device performance testing and drive innovation in the biomedical field.

Highlights

Microfluidic systems are becoming more common in biomedical applications [1,2], as evidenced by an increase in submissions of medical devices with microfluidics-based components to the U.S Food and Drug Administration (FDA) [3]
There is no consensus flow model used by the microfluidics community to study particle focusing, several research groups have investigated the physics behind particle focusing for different flow rates and types of particles [14,15,21,23,24,33,40,41,42]
Much of the current research on microfluidic-based medical devices focuses on demonstrating proof-of-principle for specific assays, while the reliability of end-devices operating under clinically relevant conditions is not always considered in the early stages of product development [55]

Summary

Introduction

Microfluidic systems are becoming more common in biomedical applications [1,2], as evidenced by an increase in submissions of medical devices with microfluidics-based components to the U.S Food and Drug Administration (FDA) [3]. The regulatory science of assessing microfluidic devices is just beginning to take shape. Tools such as standards and technical guidance will aid in product development, regulation, and process control. Standardized test methods inform guidance documents and regulations, which benefit device manufacturers by helping to establish clear and transparent expectations about the types of testing necessary for getting microfluidics products to market efficiently [4]. They are important for creating consistency across device types and manufacturers and for ensuring device safety and effectiveness. This work is intended to support and encourage the development of performance testing strategies within the microfluidics community

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Conclusion